From 9a20be984352489804230ed3a91aa9b459405a45 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Mon, 22 May 2017 16:44:45 -0700
Subject: [PATCH 01/47] Send trace context with logs from web applications

---
 .../google/cloud/logging/handlers/_helpers.py | 39 ++++++++++++++++++
 .../cloud/logging/handlers/app_engine.py      | 18 ++++++++-
 .../google/cloud/logging/handlers/handlers.py | 12 +++++-
 .../logging/handlers/middleware/__init__.py   | 17 ++++++++
 .../logging/handlers/middleware/request.py    | 40 +++++++++++++++++++
 .../handlers/transports/background_thread.py  | 13 ++++--
 .../cloud/logging/handlers/transports/base.py |  5 ++-
 .../cloud/logging/handlers/transports/sync.py | 11 ++++-
 8 files changed, 146 insertions(+), 9 deletions(-)
 create mode 100644 logging/google/cloud/logging/handlers/middleware/__init__.py
 create mode 100644 logging/google/cloud/logging/handlers/middleware/request.py

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 81adcf0eb545..97b44d53ec19 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -17,6 +17,23 @@
 import math
 import json
 
+try:
+    import django
+except ImportError:
+    _USE_DJANGO = False
+else:
+    _USE_DJANGO = True
+
+try:
+    import flask
+except ImportError:
+    _USE_FLASK = False
+    flask = None
+else:
+    _USE_FLASK = True
+
+from google.cloud.logging.handlers.middleware.request import get_request
+
 
 def format_stackdriver_json(record, message):
     """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -37,3 +54,25 @@ def format_stackdriver_json(record, message):
     }
 
     return json.dumps(payload)
+
+
+def get_trace_id_from_request_header():
+    """Helper to get trace_id from web application request header.
+
+    :rtype: str
+    :returns: Trace_id in HTTP request headers.
+    """
+    if _USE_FLASK:
+        try:
+            trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]
+        except Exception:
+            trace_id = None
+    elif _USE_DJANGO:
+        try:
+            request = get_request()
+            trace_id = request.META['HTTP_X_CLOUD_TRACE_CONTEXT'].split('/')[0]
+        except Exception:
+            trace_id = None
+    else:
+        trace_id = None
+    return trace_id
diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index c7394f32262d..6860060e071f 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -20,6 +20,7 @@
 
 import os
 
+from google.cloud.logging.handlers._helpers import get_trace_id_from_request_header
 from google.cloud.logging.handlers.handlers import CloudLoggingHandler
 from google.cloud.logging.handlers.transports import BackgroundThreadTransport
 from google.cloud.logging.resource import Resource
@@ -50,7 +51,8 @@ def __init__(self, client,
             client,
             name=_DEFAULT_GAE_LOGGER_NAME,
             transport=transport,
-            resource=self.get_gae_resource())
+            resource=self.get_gae_resource(),
+            labels=self.get_gae_labels())
 
     def get_gae_resource(self):
         """Return the GAE resource using the environment variables.
@@ -67,3 +69,17 @@ def get_gae_resource(self):
             },
         )
         return gae_resource
+
+    def get_gae_labels(self):
+        """Return the labels for GAE app which includes trace_id.
+
+        :rtype: dict
+        :returns: Labels for GAE app.
+        """
+        trace_id = get_trace_id_from_request_header()
+        if trace_id is None:
+            trace_id = 'unknown'
+        gae_labels = {
+            'appengine.googleapis.com/trace_id': trace_id,
+        }
+        return gae_labels
\ No newline at end of file
diff --git a/logging/google/cloud/logging/handlers/handlers.py b/logging/google/cloud/logging/handlers/handlers.py
index 2269c2858f33..b45b4f593bc2 100644
--- a/logging/google/cloud/logging/handlers/handlers.py
+++ b/logging/google/cloud/logging/handlers/handlers.py
@@ -57,6 +57,9 @@ class CloudLoggingHandler(logging.StreamHandler):
     :param resource: (Optional) Monitored resource of the entry, defaults
                      to the global resource type.
 
+    :type labels: dict
+    :param labels: (Optional) Mapping of labels for the entry.
+
     Example:
 
     .. code-block:: python
@@ -79,12 +82,14 @@ class CloudLoggingHandler(logging.StreamHandler):
     def __init__(self, client,
                  name=DEFAULT_LOGGER_NAME,
                  transport=BackgroundThreadTransport,
-                 resource=_GLOBAL_RESOURCE):
+                 resource=_GLOBAL_RESOURCE,
+                 labels=None):
         super(CloudLoggingHandler, self).__init__()
         self.name = name
         self.client = client
         self.transport = transport(client, name)
         self.resource = resource
+        self.labels = labels
 
     def emit(self, record):
         """Actually log the specified logging record.
@@ -97,7 +102,10 @@ def emit(self, record):
         :param record: The record to be logged.
         """
         message = super(CloudLoggingHandler, self).format(record)
-        self.transport.send(record, message, resource=self.resource)
+        self.transport.send(record,
+                            message,
+                            resource=self.resource,
+                            labels=self.labels)
 
 
 def setup_logging(handler, excluded_loggers=EXCLUDED_LOGGER_DEFAULTS,
diff --git a/logging/google/cloud/logging/handlers/middleware/__init__.py b/logging/google/cloud/logging/handlers/middleware/__init__.py
new file mode 100644
index 000000000000..79c3abee7894
--- /dev/null
+++ b/logging/google/cloud/logging/handlers/middleware/__init__.py
@@ -0,0 +1,17 @@
+# Copyright 2016 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+
+__all__ = ['RequestMiddleware']
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
new file mode 100644
index 000000000000..0c6d1f46c5cd
--- /dev/null
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -0,0 +1,40 @@
+# Copyright 2016 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+try:
+    from threading import local
+except ImportError:
+    from django.utils._threading_local import local
+
+_thread_locals = local()
+
+
+def get_request():
+    """Get Django request from thread local.
+
+    :rtype: str
+    :returns: Django request.
+    """
+    return getattr(_thread_locals, 'request', None)
+
+class RequestMiddleware(object):
+    """Saves the request in thread local"""
+
+    def process_request(self, request):
+        """Called on each request, before Django decides which view to execute.
+
+        :type request: :class:`~django.http.request.HttpRequest`
+        :param request: Django http request.
+        """
+        _thread_locals.request = request
diff --git a/logging/google/cloud/logging/handlers/transports/background_thread.py b/logging/google/cloud/logging/handlers/transports/background_thread.py
index 010c06b36bc9..d889bed62626 100644
--- a/logging/google/cloud/logging/handlers/transports/background_thread.py
+++ b/logging/google/cloud/logging/handlers/transports/background_thread.py
@@ -203,7 +203,7 @@ def _main_thread_terminated(self):
         else:
             print('Failed to send %d pending logs.' % (self._queue.qsize(),))
 
-    def enqueue(self, record, message, resource=None):
+    def enqueue(self, record, message, resource=None, labels=None):
         """Queues a log entry to be written by the background thread.
 
         :type record: :class:`logging.LogRecord`
@@ -215,6 +215,9 @@ def enqueue(self, record, message, resource=None):
 
         :type resource: :class:`~google.cloud.logging.resource.Resource`
         :param resource: (Optional) Monitored resource of the entry
+
+        :type labels: dict
+        :param labels: (Optional) Mapping of labels for the entry.
         """
         self._queue.put_nowait({
             'info': {
@@ -223,6 +226,7 @@ def enqueue(self, record, message, resource=None):
             },
             'severity': record.levelname,
             'resource': resource,
+            'labels': labels,
         })
 
     def flush(self):
@@ -257,7 +261,7 @@ def __init__(self, client, name, grace_period=_DEFAULT_GRACE_PERIOD,
         self.worker = _Worker(logger)
         self.worker.start()
 
-    def send(self, record, message, resource=None):
+    def send(self, record, message, resource=None, labels=None):
         """Overrides Transport.send().
 
         :type record: :class:`logging.LogRecord`
@@ -269,8 +273,11 @@ def send(self, record, message, resource=None):
 
         :type resource: :class:`~google.cloud.logging.resource.Resource`
         :param resource: (Optional) Monitored resource of the entry.
+
+        :type labels: dict
+        :param labels: (Optional) Mapping of labels for the entry.
         """
-        self.worker.enqueue(record, message, resource=resource)
+        self.worker.enqueue(record, message, resource=resource, labels=labels)
 
     def flush(self):
         """Submit any pending log records."""
diff --git a/logging/google/cloud/logging/handlers/transports/base.py b/logging/google/cloud/logging/handlers/transports/base.py
index 21957021793f..7829201b1c98 100644
--- a/logging/google/cloud/logging/handlers/transports/base.py
+++ b/logging/google/cloud/logging/handlers/transports/base.py
@@ -22,7 +22,7 @@ class Transport(object):
     client and name object, and must override :meth:`send`.
     """
 
-    def send(self, record, message, resource=None):
+    def send(self, record, message, resource=None, labels=None):
         """Transport send to be implemented by subclasses.
 
         :type record: :class:`logging.LogRecord`
@@ -34,6 +34,9 @@ def send(self, record, message, resource=None):
 
         :type resource: :class:`~google.cloud.logging.resource.Resource`
         :param resource: (Optional) Monitored resource of the entry.
+
+        :type labels: dict
+        :param labels: (Optional) Mapping of labels for the entry.
         """
         raise NotImplementedError
 
diff --git a/logging/google/cloud/logging/handlers/transports/sync.py b/logging/google/cloud/logging/handlers/transports/sync.py
index 0dd6e0bd7e24..be70e60a14e1 100644
--- a/logging/google/cloud/logging/handlers/transports/sync.py
+++ b/logging/google/cloud/logging/handlers/transports/sync.py
@@ -29,7 +29,7 @@ class SyncTransport(Transport):
     def __init__(self, client, name):
         self.logger = client.logger(name)
 
-    def send(self, record, message, resource=None):
+    def send(self, record, message, resource=None, labels=None):
         """Overrides transport.send().
 
         :type record: :class:`logging.LogRecord`
@@ -38,8 +38,15 @@ def send(self, record, message, resource=None):
         :type message: str
         :param message: The message from the ``LogRecord`` after being
                         formatted by the associated log formatters.
+
+        :type resource: :class:`~google.cloud.logging.resource.Resource`
+        :param resource: (Optional) Monitored resource of the entry.
+
+        :type labels: dict
+        :param labels: (Optional) Mapping of labels for the entry.
         """
         info = {'message': message, 'python_logger': record.name}
         self.logger.log_struct(info,
                                severity=record.levelname,
-                               resource=resource)
+                               resource=resource,
+                               labels=labels)

From cf283c4e4983ea6077506c5d8abe928a8b7bb1d1 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Mon, 22 May 2017 16:58:43 -0700
Subject: [PATCH 02/47] Fix style

---
 logging/google/cloud/logging/handlers/app_engine.py         | 2 +-
 logging/google/cloud/logging/handlers/middleware/request.py | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index 6860060e071f..ea4cc9245282 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -82,4 +82,4 @@ def get_gae_labels(self):
         gae_labels = {
             'appengine.googleapis.com/trace_id': trace_id,
         }
-        return gae_labels
\ No newline at end of file
+        return gae_labels
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index 0c6d1f46c5cd..a37a6af47035 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -28,6 +28,7 @@ def get_request():
     """
     return getattr(_thread_locals, 'request', None)
 
+
 class RequestMiddleware(object):
     """Saves the request in thread local"""
 

From 583d076f53d1c10eba3633e24c83a00e4e612598 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Tue, 23 May 2017 14:23:32 -0700
Subject: [PATCH 03/47] Improved code for web framework detection

---
 .../google/cloud/logging/handlers/_helpers.py | 37 ++++++++++++++-----
 1 file changed, 27 insertions(+), 10 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 97b44d53ec19..a1c697ba404c 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -16,24 +16,18 @@
 
 import math
 import json
-
-try:
-    import django
-except ImportError:
-    _USE_DJANGO = False
-else:
-    _USE_DJANGO = True
+import sys
 
 try:
     import flask
 except ImportError:
-    _USE_FLASK = False
     flask = None
-else:
-    _USE_FLASK = True
 
 from google.cloud.logging.handlers.middleware.request import get_request
 
+_USE_FLASK = False
+_USE_DJANGO = False
+
 
 def format_stackdriver_json(record, message):
     """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -56,12 +50,35 @@ def format_stackdriver_json(record, message):
     return json.dumps(payload)
 
 
+def detect_web_framework():
+    """Detect web framework used in this environment.
+
+    Detect which web framework is used by looking at the sys.modules.
+    If multiple or no supported web frameworks detected in the modules, then
+    print a warning message.
+    Set _USE_FLASK or _USE_DJANGO to True if one of them are detected.
+    """
+    modules = sys.modules
+    global _USE_FLASK, _USE_DJANGO
+
+    if 'flask' in modules and 'django' in modules:
+        print('Cannot determine, found multiple web frameworks.')
+    elif 'flask' in modules:
+        _USE_FLASK = True
+    elif 'django' in modules:
+        _USE_DJANGO = True
+    else:
+        print('No supported web framework found in the modules.')
+
+
 def get_trace_id_from_request_header():
     """Helper to get trace_id from web application request header.
 
     :rtype: str
     :returns: Trace_id in HTTP request headers.
     """
+    detect_web_framework()
+
     if _USE_FLASK:
         try:
             trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]

From 5be368e1410dbff2a2f4009f3887ffbdfb06c139 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Tue, 23 May 2017 14:28:01 -0700
Subject: [PATCH 04/47] Fix year

---
 logging/google/cloud/logging/handlers/middleware/__init__.py | 2 +-
 logging/google/cloud/logging/handlers/middleware/request.py  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/middleware/__init__.py b/logging/google/cloud/logging/handlers/middleware/__init__.py
index 79c3abee7894..c340235b8bdd 100644
--- a/logging/google/cloud/logging/handlers/middleware/__init__.py
+++ b/logging/google/cloud/logging/handlers/middleware/__init__.py
@@ -1,4 +1,4 @@
-# Copyright 2016 Google Inc. All Rights Reserved.
+# Copyright 2017 Google Inc. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index a37a6af47035..be5102487cc6 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -1,4 +1,4 @@
-# Copyright 2016 Google Inc. All Rights Reserved.
+# Copyright 2017 Google Inc. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.

From 28e3a6c119b1b2ddaaf7cac45d39ab6e5c21a2b7 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Tue, 23 May 2017 14:45:28 -0700
Subject: [PATCH 05/47] Drop module level variables

---
 .../google/cloud/logging/handlers/_helpers.py | 22 ++++++++++---------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index a1c697ba404c..6bf0edf79d54 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -25,9 +25,6 @@
 
 from google.cloud.logging.handlers.middleware.request import get_request
 
-_USE_FLASK = False
-_USE_DJANGO = False
-
 
 def format_stackdriver_json(record, message):
     """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -56,19 +53,24 @@ def detect_web_framework():
     Detect which web framework is used by looking at the sys.modules.
     If multiple or no supported web frameworks detected in the modules, then
     print a warning message.
-    Set _USE_FLASK or _USE_DJANGO to True if one of them are detected.
+    Return the name of web framework detected if flask or django is found.
+    Return unknown if cannot determine.
+
+    :rtype: str
+    :returns: Web framework detected in this environment.
     """
     modules = sys.modules
-    global _USE_FLASK, _USE_DJANGO
+    web_framework = 'unknown'
 
     if 'flask' in modules and 'django' in modules:
         print('Cannot determine, found multiple web frameworks.')
     elif 'flask' in modules:
-        _USE_FLASK = True
+        web_framework = 'flask'
     elif 'django' in modules:
-        _USE_DJANGO = True
+        web_framework = 'django'
     else:
         print('No supported web framework found in the modules.')
+    return web_framework
 
 
 def get_trace_id_from_request_header():
@@ -77,14 +79,14 @@ def get_trace_id_from_request_header():
     :rtype: str
     :returns: Trace_id in HTTP request headers.
     """
-    detect_web_framework()
+    web_framework = detect_web_framework()
 
-    if _USE_FLASK:
+    if web_framework is 'flask':
         try:
             trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]
         except Exception:
             trace_id = None
-    elif _USE_DJANGO:
+    elif web_framework is 'django':
         try:
             request = get_request()
             trace_id = request.META['HTTP_X_CLOUD_TRACE_CONTEXT'].split('/')[0]

From cdc96b4fcc6668a56af66ea46d482bf47942e4a4 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Thu, 25 May 2017 10:07:25 -0700
Subject: [PATCH 06/47] Address Jon's comments and add some unit tests (not
 complete yet)

---
 .../google/cloud/logging/handlers/_helpers.py | 66 ++++++++-----------
 .../cloud/logging/handlers/app_engine.py      |  4 +-
 .../google/cloud/logging/handlers/handlers.py |  9 +--
 .../logging/handlers/middleware/request.py    |  6 +-
 .../tests/unit/handlers/test_app_engine.py    | 11 +++-
 logging/tests/unit/handlers/test_handlers.py  |  6 +-
 .../transports/test_background_thread.py      |  8 +--
 .../unit/handlers/transports/test_sync.py     |  6 +-
 8 files changed, 56 insertions(+), 60 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 6bf0edf79d54..0af7a53de476 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -16,7 +16,6 @@
 
 import math
 import json
-import sys
 
 try:
     import flask
@@ -47,51 +46,44 @@ def format_stackdriver_json(record, message):
     return json.dumps(payload)
 
 
-def detect_web_framework():
-    """Detect web framework used in this environment.
-
-    Detect which web framework is used by looking at the sys.modules.
-    If multiple or no supported web frameworks detected in the modules, then
-    print a warning message.
-    Return the name of web framework detected if flask or django is found.
-    Return unknown if cannot determine.
+def get_trace_id_from_flask():
+    """Get trace_id from flask request headers.
 
     :rtype: str
-    :returns: Web framework detected in this environment.
+    :return: Trace_id in HTTP request headers.
     """
-    modules = sys.modules
-    web_framework = 'unknown'
+    try:
+        trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]
+    except Exception:
+        trace_id = None
+    return trace_id
 
-    if 'flask' in modules and 'django' in modules:
-        print('Cannot determine, found multiple web frameworks.')
-    elif 'flask' in modules:
-        web_framework = 'flask'
-    elif 'django' in modules:
-        web_framework = 'django'
-    else:
-        print('No supported web framework found in the modules.')
-    return web_framework
+
+def get_trace_id_from_django():
+    """Get trace_id from django request headers.
+
+    :rtype: str
+    :return: Trace_id in HTTP request headers.
+    """
+    try:
+        request = get_request()
+        trace_id = request.META['HTTP_X_CLOUD_TRACE_CONTEXT'].split('/')[0]
+    except Exception:
+        trace_id = None
+    return trace_id
 
 
-def get_trace_id_from_request_header():
+def get_trace_id():
     """Helper to get trace_id from web application request header.
 
     :rtype: str
     :returns: Trace_id in HTTP request headers.
     """
-    web_framework = detect_web_framework()
-
-    if web_framework is 'flask':
-        try:
-            trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]
-        except Exception:
-            trace_id = None
-    elif web_framework is 'django':
-        try:
-            request = get_request()
-            trace_id = request.META['HTTP_X_CLOUD_TRACE_CONTEXT'].split('/')[0]
-        except Exception:
-            trace_id = None
-    else:
-        trace_id = None
+    checkers = [get_trace_id_from_django, get_trace_id_from_flask]
+
+    for checker in checkers:
+        trace_id = checker()
+        if trace_id is not None:
+            return trace_id
+
     return trace_id
diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index ea4cc9245282..7bf4790e0603 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -20,7 +20,7 @@
 
 import os
 
-from google.cloud.logging.handlers._helpers import get_trace_id_from_request_header
+from google.cloud.logging.handlers._helpers import get_trace_id
 from google.cloud.logging.handlers.handlers import CloudLoggingHandler
 from google.cloud.logging.handlers.transports import BackgroundThreadTransport
 from google.cloud.logging.resource import Resource
@@ -76,7 +76,7 @@ def get_gae_labels(self):
         :rtype: dict
         :returns: Labels for GAE app.
         """
-        trace_id = get_trace_id_from_request_header()
+        trace_id = get_trace_id()
         if trace_id is None:
             trace_id = 'unknown'
         gae_labels = {
diff --git a/logging/google/cloud/logging/handlers/handlers.py b/logging/google/cloud/logging/handlers/handlers.py
index b45b4f593bc2..26343ec9f9c5 100644
--- a/logging/google/cloud/logging/handlers/handlers.py
+++ b/logging/google/cloud/logging/handlers/handlers.py
@@ -102,10 +102,11 @@ def emit(self, record):
         :param record: The record to be logged.
         """
         message = super(CloudLoggingHandler, self).format(record)
-        self.transport.send(record,
-                            message,
-                            resource=self.resource,
-                            labels=self.labels)
+        self.transport.send(
+            record,
+            message,
+            resource=self.resource,
+            labels=self.labels)
 
 
 def setup_logging(handler, excluded_loggers=EXCLUDED_LOGGER_DEFAULTS,
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index be5102487cc6..92bfd4369b00 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -12,10 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-try:
-    from threading import local
-except ImportError:
-    from django.utils._threading_local import local
+from threading import local
+
 
 _thread_locals = local()
 
diff --git a/logging/tests/unit/handlers/test_app_engine.py b/logging/tests/unit/handlers/test_app_engine.py
index c39328593f7a..99f5ea93625a 100644
--- a/logging/tests/unit/handlers/test_app_engine.py
+++ b/logging/tests/unit/handlers/test_app_engine.py
@@ -34,6 +34,7 @@ def test_constructor(self):
         from google.cloud.logging.handlers.app_engine import _GAE_VERSION_ENV
 
         client = mock.Mock(project=self.PROJECT, spec=['project'])
+
         with mock.patch('os.environ', new={_GAE_PROJECT_ENV: 'test_project',
                                            _GAE_SERVICE_ENV: 'test_service',
                                            _GAE_VERSION_ENV: 'test_version'}):
@@ -43,6 +44,7 @@ def test_constructor(self):
         self.assertEqual(handler.resource.labels['project_id'], 'test_project')
         self.assertEqual(handler.resource.labels['module_id'], 'test_service')
         self.assertEqual(handler.resource.labels['version_id'], 'test_version')
+        self.assertEqual(handler.labels['appengine.googleapis.com/trace_id'], 'unknown')
 
     def test_emit(self):
         import mock
@@ -50,6 +52,7 @@ def test_emit(self):
         client = mock.Mock(project=self.PROJECT, spec=['project'])
         handler = self._make_one(client, transport=_Transport)
         gae_resource = handler.get_gae_resource()
+        gae_labels = handler.get_gae_labels()
         logname = 'app'
         message = 'hello world'
         record = logging.LogRecord(logname, logging, None, None, message,
@@ -58,7 +61,9 @@ def test_emit(self):
 
         self.assertIs(handler.transport.client, client)
         self.assertEqual(handler.transport.name, logname)
-        self.assertEqual(handler.transport.send_called_with, (record, message, gae_resource))
+        self.assertEqual(
+            handler.transport.send_called_with,
+            (record, message, gae_resource, gae_labels))
 
 
 class _Transport(object):
@@ -67,5 +72,5 @@ def __init__(self, client, name):
         self.client = client
         self.name = name
 
-    def send(self, record, message, resource):
-        self.send_called_with = (record, message, resource)
+    def send(self, record, message, resource, labels):
+        self.send_called_with = (record, message, resource, labels)
diff --git a/logging/tests/unit/handlers/test_handlers.py b/logging/tests/unit/handlers/test_handlers.py
index 05dc87631478..5459a0c10b96 100644
--- a/logging/tests/unit/handlers/test_handlers.py
+++ b/logging/tests/unit/handlers/test_handlers.py
@@ -45,7 +45,7 @@ def test_emit(self):
                                    None, None)
         handler.emit(record)
 
-        self.assertEqual(handler.transport.send_called_with, (record, message, _GLOBAL_RESOURCE))
+        self.assertEqual(handler.transport.send_called_with, (record, message, _GLOBAL_RESOURCE, None))
 
 
 class TestSetupLogging(unittest.TestCase):
@@ -110,5 +110,5 @@ class _Transport(object):
     def __init__(self, client, name):
         pass
 
-    def send(self, record, message, resource):
-        self.send_called_with = (record, message, resource)
+    def send(self, record, message, resource, labels=None):
+        self.send_called_with = (record, message, resource, labels)
diff --git a/logging/tests/unit/handlers/transports/test_background_thread.py b/logging/tests/unit/handlers/transports/test_background_thread.py
index 3e3378dcd361..b9449ce56685 100644
--- a/logging/tests/unit/handlers/transports/test_background_thread.py
+++ b/logging/tests/unit/handlers/transports/test_background_thread.py
@@ -61,9 +61,9 @@ def test_send(self):
             python_logger_name, logging.INFO,
             None, None, message, None, None)
 
-        transport.send(record, message, _GLOBAL_RESOURCE)
+        transport.send(record, message, _GLOBAL_RESOURCE, None)
 
-        transport.worker.enqueue.assert_called_once_with(record, message, _GLOBAL_RESOURCE)
+        transport.worker.enqueue.assert_called_once_with(record, message, _GLOBAL_RESOURCE, None)
 
     def test_flush(self):
         client = _Client(self.PROJECT)
@@ -287,13 +287,13 @@ def __init__(self):
         self.commit_called = False
         self.commit_count = None
 
-    def log_struct(self, info, severity=logging.INFO, resource=None):
+    def log_struct(self, info, severity=logging.INFO, resource=None, labels=None):
         from google.cloud.logging.logger import _GLOBAL_RESOURCE
 
         assert resource is None
         resource = _GLOBAL_RESOURCE
 
-        self.log_struct_called_with = (info, severity, resource)
+        self.log_struct_called_with = (info, severity, resource, labels)
         self.entries.append(info)
 
     def commit(self):
diff --git a/logging/tests/unit/handlers/transports/test_sync.py b/logging/tests/unit/handlers/transports/test_sync.py
index 475ecc9c6a71..e18920ce2167 100644
--- a/logging/tests/unit/handlers/transports/test_sync.py
+++ b/logging/tests/unit/handlers/transports/test_sync.py
@@ -52,7 +52,7 @@ def test_send(self):
             'message': message,
             'python_logger': python_logger_name,
         }
-        EXPECTED_SENT = (EXPECTED_STRUCT, 'INFO', _GLOBAL_RESOURCE)
+        EXPECTED_SENT = (EXPECTED_STRUCT, 'INFO', _GLOBAL_RESOURCE, None)
         self.assertEqual(
             transport.logger.log_struct_called_with, EXPECTED_SENT)
 
@@ -63,8 +63,8 @@ class _Logger(object):
     def __init__(self, name):
         self.name = name
 
-    def log_struct(self, message, severity=None, resource=_GLOBAL_RESOURCE):
-        self.log_struct_called_with = (message, severity, resource)
+    def log_struct(self, message, severity=None, resource=_GLOBAL_RESOURCE, labels=None):
+        self.log_struct_called_with = (message, severity, resource, labels)
 
 
 class _Client(object):

From fb83ab6e9cf556bd2c7a0063cc38a3ed5c4d933c Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Thu, 25 May 2017 10:45:36 -0700
Subject: [PATCH 07/47] Fix stuff

---
 .../google/cloud/logging/handlers/_helpers.py | 35 ++++++++++++++-----
 .../logging/handlers/middleware/request.py    | 17 +++++----
 .../tests/unit/handlers/test_app_engine.py    |  4 ++-
 3 files changed, 37 insertions(+), 19 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 0af7a53de476..ca94e17ebb92 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -22,7 +22,10 @@
 except ImportError:
     flask = None
 
-from google.cloud.logging.handlers.middleware.request import get_request
+from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+
+_FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
+_DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
 
 
 def format_stackdriver_json(record, message):
@@ -52,10 +55,16 @@ def get_trace_id_from_flask():
     :rtype: str
     :return: Trace_id in HTTP request headers.
     """
-    try:
-        trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]
-    except Exception:
-        trace_id = None
+    if not flask or not flask.request:
+        return None
+
+    header = flask.request.headers.get(_FLASK_TRACE_HEADER)
+
+    if not header:
+        return None
+
+    trace_id = header.split('/')[0]
+
     return trace_id
 
 
@@ -65,11 +74,19 @@ def get_trace_id_from_django():
     :rtype: str
     :return: Trace_id in HTTP request headers.
     """
+    request_middleware = RequestMiddleware()
+    request = request_middleware.get_request()
+
+    if not request:
+        return None
+
     try:
-        request = get_request()
-        trace_id = request.META['HTTP_X_CLOUD_TRACE_CONTEXT'].split('/')[0]
-    except Exception:
-        trace_id = None
+        header = request.META[_DJANGO_TRACE_HEADER]
+    except KeyError:
+        return None
+
+    trace_id = header.split('/')[0]
+
     return trace_id
 
 
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index 92bfd4369b00..7e0e89f6aa39 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -18,15 +18,6 @@
 _thread_locals = local()
 
 
-def get_request():
-    """Get Django request from thread local.
-
-    :rtype: str
-    :returns: Django request.
-    """
-    return getattr(_thread_locals, 'request', None)
-
-
 class RequestMiddleware(object):
     """Saves the request in thread local"""
 
@@ -37,3 +28,11 @@ def process_request(self, request):
         :param request: Django http request.
         """
         _thread_locals.request = request
+
+    def get_request(self):
+        """Get Django request from thread local.
+
+        :rtype: str
+        :returns: Django request.
+        """
+        return getattr(_thread_locals, 'request', None)
diff --git a/logging/tests/unit/handlers/test_app_engine.py b/logging/tests/unit/handlers/test_app_engine.py
index 99f5ea93625a..0f8ace3a95e7 100644
--- a/logging/tests/unit/handlers/test_app_engine.py
+++ b/logging/tests/unit/handlers/test_app_engine.py
@@ -33,6 +33,8 @@ def test_constructor(self):
         from google.cloud.logging.handlers.app_engine import _GAE_SERVICE_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_VERSION_ENV
 
+        TRACE_ID_LABEL = 'appengine.googleapis.com/trace_id'
+
         client = mock.Mock(project=self.PROJECT, spec=['project'])
 
         with mock.patch('os.environ', new={_GAE_PROJECT_ENV: 'test_project',
@@ -44,7 +46,7 @@ def test_constructor(self):
         self.assertEqual(handler.resource.labels['project_id'], 'test_project')
         self.assertEqual(handler.resource.labels['module_id'], 'test_service')
         self.assertEqual(handler.resource.labels['version_id'], 'test_version')
-        self.assertEqual(handler.labels['appengine.googleapis.com/trace_id'], 'unknown')
+        self.assertEqual(handler.labels[TRACE_ID_LABEL], 'unknown')
 
     def test_emit(self):
         import mock

From 9a20c4e013b7f8c03f83447fd604bdf5ce5bc9e6 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Thu, 25 May 2017 14:54:23 -0700
Subject: [PATCH 08/47] Add unit test for flask and some refactor

---
 .../google/cloud/logging/handlers/_helpers.py | 12 ++--
 .../cloud/logging/handlers/app_engine.py      |  2 -
 logging/nox.py                                |  2 +-
 logging/tests/unit/handlers/test__helpers.py  | 57 +++++++++++++++++++
 .../tests/unit/handlers/test_app_engine.py    |  3 +-
 5 files changed, 67 insertions(+), 9 deletions(-)
 create mode 100644 logging/tests/unit/handlers/test__helpers.py

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index ca94e17ebb92..17caf76e4aa9 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -27,6 +27,8 @@
 _FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
 _DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
 
+_EMPTY_TRACE_ID = 'None'
+
 
 def format_stackdriver_json(record, message):
     """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -56,12 +58,12 @@ def get_trace_id_from_flask():
     :return: Trace_id in HTTP request headers.
     """
     if not flask or not flask.request:
-        return None
+        return _EMPTY_TRACE_ID
 
     header = flask.request.headers.get(_FLASK_TRACE_HEADER)
 
     if not header:
-        return None
+        return _EMPTY_TRACE_ID
 
     trace_id = header.split('/')[0]
 
@@ -78,12 +80,12 @@ def get_trace_id_from_django():
     request = request_middleware.get_request()
 
     if not request:
-        return None
+        return _EMPTY_TRACE_ID
 
     try:
         header = request.META[_DJANGO_TRACE_HEADER]
     except KeyError:
-        return None
+        return _EMPTY_TRACE_ID
 
     trace_id = header.split('/')[0]
 
@@ -100,7 +102,7 @@ def get_trace_id():
 
     for checker in checkers:
         trace_id = checker()
-        if trace_id is not None:
+        if trace_id is not _EMPTY_TRACE_ID:
             return trace_id
 
     return trace_id
diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index 7bf4790e0603..daa48132e246 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -77,8 +77,6 @@ def get_gae_labels(self):
         :returns: Labels for GAE app.
         """
         trace_id = get_trace_id()
-        if trace_id is None:
-            trace_id = 'unknown'
         gae_labels = {
             'appengine.googleapis.com/trace_id': trace_id,
         }
diff --git a/logging/nox.py b/logging/nox.py
index 5d4751a955a5..11d484b232e7 100644
--- a/logging/nox.py
+++ b/logging/nox.py
@@ -31,7 +31,7 @@ def unit_tests(session, python_version):
     session.interpreter = 'python{}'.format(python_version)
 
     # Install all test dependencies, then install this package in-place.
-    session.install('mock', 'pytest', 'pytest-cov', *LOCAL_DEPS)
+    session.install('mock', 'pytest', 'pytest-cov', 'flask', *LOCAL_DEPS)
     session.install('-e', '.')
 
     # Run py.test against the unit tests.
diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
new file mode 100644
index 000000000000..db9d51d27920
--- /dev/null
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -0,0 +1,57 @@
+# Copyright 2017 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+
+
+class TestFlaskTrace(unittest.TestCase):
+
+    def create_app(self):
+        import flask
+
+        app = flask.Flask(__name__)
+
+        @app.route('/')
+        def index():
+            return 'test flask trace'
+
+        return app
+
+    def setUp(self):
+        self.app = self.create_app()
+
+    def test_trace_id_no_context_header(self):
+        from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
+        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
+
+        with self.app.test_request_context(
+                path='/',
+                headers={}):
+            trace_id = get_trace_id_from_flask()
+
+        self.assertEqual(trace_id, _EMPTY_TRACE_ID)
+
+    def test_trace_id_valid_context_header(self):
+        from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
+
+        FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
+        FLASK_TRACE_ID = 'testtraceid/testspanid'
+
+        with self.app.test_request_context(
+                path='/',
+                headers={FLASK_TRACE_HEADER:FLASK_TRACE_ID}):
+            trace_id = get_trace_id_from_flask()
+
+        EXPECTED_TRACE_ID = 'testtraceid'
+        self.assertEqual(trace_id, EXPECTED_TRACE_ID)
diff --git a/logging/tests/unit/handlers/test_app_engine.py b/logging/tests/unit/handlers/test_app_engine.py
index 0f8ace3a95e7..886dbbbb5584 100644
--- a/logging/tests/unit/handlers/test_app_engine.py
+++ b/logging/tests/unit/handlers/test_app_engine.py
@@ -32,6 +32,7 @@ def test_constructor(self):
         from google.cloud.logging.handlers.app_engine import _GAE_PROJECT_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_SERVICE_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_VERSION_ENV
+        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
 
         TRACE_ID_LABEL = 'appengine.googleapis.com/trace_id'
 
@@ -46,7 +47,7 @@ def test_constructor(self):
         self.assertEqual(handler.resource.labels['project_id'], 'test_project')
         self.assertEqual(handler.resource.labels['module_id'], 'test_service')
         self.assertEqual(handler.resource.labels['version_id'], 'test_version')
-        self.assertEqual(handler.labels[TRACE_ID_LABEL], 'unknown')
+        self.assertEqual(handler.labels[TRACE_ID_LABEL], _EMPTY_TRACE_ID)
 
     def test_emit(self):
         import mock

From f8b7e65acb7e1229252588264f16445f859011af Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 26 May 2017 10:20:56 -0700
Subject: [PATCH 09/47] Add unit test for middleware

---
 logging/nox.py                                |  2 +-
 .../unit/handlers/middleware/test_request.py  | 39 +++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)
 create mode 100644 logging/tests/unit/handlers/middleware/test_request.py

diff --git a/logging/nox.py b/logging/nox.py
index 11d484b232e7..de975600fd04 100644
--- a/logging/nox.py
+++ b/logging/nox.py
@@ -31,7 +31,7 @@ def unit_tests(session, python_version):
     session.interpreter = 'python{}'.format(python_version)
 
     # Install all test dependencies, then install this package in-place.
-    session.install('mock', 'pytest', 'pytest-cov', 'flask', *LOCAL_DEPS)
+    session.install('mock', 'pytest', 'pytest-cov', 'flask', 'django', *LOCAL_DEPS)
     session.install('-e', '.')
 
     # Run py.test against the unit tests.
diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
new file mode 100644
index 000000000000..ad784b45c48e
--- /dev/null
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -0,0 +1,39 @@
+# Copyright 2017 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+
+
+class TestRequestMiddleware(unittest.TestCase):
+
+    def _get_target_class(self):
+        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+
+        return RequestMiddleware
+
+    def _make_one(self, *args, **kw):
+        return self._get_target_class()(*args, **kw)
+
+    def test_get_request(self):
+        from django.conf import settings
+        from django.test.utils import setup_test_environment
+        from django.test import RequestFactory
+
+        settings.configure()
+        setup_test_environment()
+
+        self.middleware = self._make_one()
+        self.request = RequestFactory().get('/')
+        self.middleware.process_request(self.request)
+        self.assertEqual(self.middleware.get_request(), self.request)

From 65efdcd79fbcae278c0ad925c367d902b408f9ab Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 26 May 2017 11:25:41 -0700
Subject: [PATCH 10/47] Add unit test for django

---
 .../unit/handlers/middleware/test_request.py  | 15 ++++-
 logging/tests/unit/handlers/test__helpers.py  | 67 ++++++++++++++++++-
 2 files changed, 77 insertions(+), 5 deletions(-)

diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
index ad784b45c48e..5b6dfca8dc67 100644
--- a/logging/tests/unit/handlers/middleware/test_request.py
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -25,15 +25,24 @@ def _get_target_class(self):
     def _make_one(self, *args, **kw):
         return self._get_target_class()(*args, **kw)
 
-    def test_get_request(self):
+    def setUp(self):
         from django.conf import settings
         from django.test.utils import setup_test_environment
-        from django.test import RequestFactory
 
-        settings.configure()
+        if not settings.configured:
+            settings.configure()
         setup_test_environment()
 
+    def test_get_request(self):
+        from django.test import RequestFactory
+
         self.middleware = self._make_one()
         self.request = RequestFactory().get('/')
         self.middleware.process_request(self.request)
         self.assertEqual(self.middleware.get_request(), self.request)
+
+
+    def tearDown(self):
+        from django.test.utils import teardown_test_environment
+
+        teardown_test_environment()
diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
index db9d51d27920..3d023dd8f9cf 100644
--- a/logging/tests/unit/handlers/test__helpers.py
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -33,25 +33,88 @@ def setUp(self):
 
     def test_trace_id_no_context_header(self):
         from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
+        from google.cloud.logging.handlers._helpers import get_trace_id
         from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
 
         with self.app.test_request_context(
                 path='/',
                 headers={}):
             trace_id = get_trace_id_from_flask()
+            trace_id_returned = get_trace_id()
 
         self.assertEqual(trace_id, _EMPTY_TRACE_ID)
+        self.assertEqual(trace_id_returned, _EMPTY_TRACE_ID)
 
     def test_trace_id_valid_context_header(self):
         from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
+        from google.cloud.logging.handlers._helpers import get_trace_id
 
         FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
-        FLASK_TRACE_ID = 'testtraceid/testspanid'
+        FLASK_TRACE_ID = 'testtraceidflask/testspanid'
 
         with self.app.test_request_context(
                 path='/',
                 headers={FLASK_TRACE_HEADER:FLASK_TRACE_ID}):
             trace_id = get_trace_id_from_flask()
+            trace_id_returned = get_trace_id()
 
-        EXPECTED_TRACE_ID = 'testtraceid'
+        EXPECTED_TRACE_ID = 'testtraceidflask'
         self.assertEqual(trace_id, EXPECTED_TRACE_ID)
+        self.assertEqual(trace_id, trace_id_returned)
+
+
+class TestDjangoTrace(unittest.TestCase):
+
+    def setUp(self):
+        from django.conf import settings
+        from django.test.utils import setup_test_environment
+
+        if not settings.configured:
+            settings.configure()
+        setup_test_environment()
+
+    def test_trace_id_no_context_header(self):
+        import mock
+        from django.test import RequestFactory
+        from google.cloud.logging.handlers._helpers import get_trace_id_from_django
+        from google.cloud.logging.handlers._helpers import get_trace_id
+        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
+
+        request = RequestFactory().get('/')
+
+        with mock.patch(
+                'google.cloud.logging.handlers.middleware.RequestMiddleware.get_request',
+                return_value=request):
+            trace_id = get_trace_id_from_django()
+            trace_id_returned = get_trace_id()
+
+        self.assertEqual(trace_id, _EMPTY_TRACE_ID)
+        self.assertEqual(trace_id_returned, _EMPTY_TRACE_ID)
+
+    def test_trace_id_valid_context_header(self):
+        import mock
+        from django.test import RequestFactory
+        from google.cloud.logging.handlers._helpers import get_trace_id_from_django
+        from google.cloud.logging.handlers._helpers import get_trace_id
+
+        DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
+        DJANGO_TRACE_ID = 'testtraceiddjango/testspanid'
+
+        request = RequestFactory().get(
+            '/',
+            **{DJANGO_TRACE_HEADER:DJANGO_TRACE_ID})
+
+        with mock.patch(
+                'google.cloud.logging.handlers.middleware.RequestMiddleware.get_request',
+                return_value=request):
+            trace_id = get_trace_id_from_django()
+            trace_id_returned = get_trace_id()
+
+        EXPECTED_TRACE_ID = 'testtraceiddjango'
+        self.assertEqual(trace_id, EXPECTED_TRACE_ID)
+        self.assertEqual(trace_id, trace_id_returned)
+
+    def tearDown(self):
+        from django.test.utils import teardown_test_environment
+
+        teardown_test_environment()

From f78cc2e91905f41d86fe6251ce8c340cad3c74b1 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 26 May 2017 11:29:54 -0700
Subject: [PATCH 11/47] Fix style

---
 logging/tests/unit/handlers/middleware/test_request.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
index 5b6dfca8dc67..0aa950263f5d 100644
--- a/logging/tests/unit/handlers/middleware/test_request.py
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -41,7 +41,6 @@ def test_get_request(self):
         self.middleware.process_request(self.request)
         self.assertEqual(self.middleware.get_request(), self.request)
 
-
     def tearDown(self):
         from django.test.utils import teardown_test_environment
 

From 33b92dd16640b574e956dc0a070a081bb041ff54 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 26 May 2017 14:38:45 -0700
Subject: [PATCH 12/47] Address jon's comments

---
 .../google/cloud/logging/handlers/_helpers.py | 17 ++---
 .../cloud/logging/handlers/app_engine.py      | 10 ++-
 .../logging/handlers/middleware/request.py    | 17 ++---
 .../unit/handlers/middleware/test_request.py  | 13 ++--
 logging/tests/unit/handlers/test__helpers.py  | 66 ++++++++++---------
 .../tests/unit/handlers/test_app_engine.py    |  6 +-
 6 files changed, 66 insertions(+), 63 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 17caf76e4aa9..2c88f427f00b 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -22,13 +22,11 @@
 except ImportError:
     flask = None
 
-from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+from google.cloud.logging.handlers.middleware.request import _get_request
 
 _FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
 _DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
 
-_EMPTY_TRACE_ID = 'None'
-
 
 def format_stackdriver_json(record, message):
     """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -58,12 +56,12 @@ def get_trace_id_from_flask():
     :return: Trace_id in HTTP request headers.
     """
     if not flask or not flask.request:
-        return _EMPTY_TRACE_ID
+        return None
 
     header = flask.request.headers.get(_FLASK_TRACE_HEADER)
 
     if not header:
-        return _EMPTY_TRACE_ID
+        return None
 
     trace_id = header.split('/')[0]
 
@@ -76,16 +74,15 @@ def get_trace_id_from_django():
     :rtype: str
     :return: Trace_id in HTTP request headers.
     """
-    request_middleware = RequestMiddleware()
-    request = request_middleware.get_request()
+    request = _get_request()
 
     if not request:
-        return _EMPTY_TRACE_ID
+        return None
 
     try:
         header = request.META[_DJANGO_TRACE_HEADER]
     except KeyError:
-        return _EMPTY_TRACE_ID
+        return None
 
     trace_id = header.split('/')[0]
 
@@ -102,7 +99,7 @@ def get_trace_id():
 
     for checker in checkers:
         trace_id = checker()
-        if trace_id is not _EMPTY_TRACE_ID:
+        if trace_id is not None:
             return trace_id
 
     return trace_id
diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index daa48132e246..f8b12c44a42e 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -31,6 +31,8 @@
 _GAE_SERVICE_ENV = 'GAE_SERVICE'
 _GAE_VERSION_ENV = 'GAE_VERSION'
 
+_TRACE_ID_LABEL = 'appengine.googleapis.com/trace_id'
+
 
 class AppEngineHandler(CloudLoggingHandler):
     """A logging handler that sends App Engine-formatted logs to Stackdriver.
@@ -76,8 +78,10 @@ def get_gae_labels(self):
         :rtype: dict
         :returns: Labels for GAE app.
         """
+        gae_labels = {}
+
         trace_id = get_trace_id()
-        gae_labels = {
-            'appengine.googleapis.com/trace_id': trace_id,
-        }
+        if trace_id is not None:
+            gae_labels[_TRACE_ID_LABEL] = trace_id
+
         return gae_labels
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index 7e0e89f6aa39..9baf11f4dbbe 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -18,6 +18,15 @@
 _thread_locals = local()
 
 
+def _get_request():
+    """Get Django request from thread local.
+
+    :rtype: str
+    :returns: Django request.
+    """
+    return getattr(_thread_locals, 'request', None)
+
+
 class RequestMiddleware(object):
     """Saves the request in thread local"""
 
@@ -28,11 +37,3 @@ def process_request(self, request):
         :param request: Django http request.
         """
         _thread_locals.request = request
-
-    def get_request(self):
-        """Get Django request from thread local.
-
-        :rtype: str
-        :returns: Django request.
-        """
-        return getattr(_thread_locals, 'request', None)
diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
index 0aa950263f5d..349247805104 100644
--- a/logging/tests/unit/handlers/middleware/test_request.py
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -33,15 +33,16 @@ def setUp(self):
             settings.configure()
         setup_test_environment()
 
+    def tearDown(self):
+        from django.test.utils import teardown_test_environment
+
+        teardown_test_environment()
+
     def test_get_request(self):
         from django.test import RequestFactory
+        from google.cloud.logging.handlers.middleware.request import _get_request
 
         self.middleware = self._make_one()
         self.request = RequestFactory().get('/')
         self.middleware.process_request(self.request)
-        self.assertEqual(self.middleware.get_request(), self.request)
-
-    def tearDown(self):
-        from django.test.utils import teardown_test_environment
-
-        teardown_test_environment()
+        self.assertEqual(_get_request(), self.request)
diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
index 3d023dd8f9cf..634ceb26e8a6 100644
--- a/logging/tests/unit/handlers/test__helpers.py
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -34,7 +34,6 @@ def setUp(self):
     def test_trace_id_no_context_header(self):
         from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
         from google.cloud.logging.handlers._helpers import get_trace_id
-        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
 
         with self.app.test_request_context(
                 path='/',
@@ -42,24 +41,24 @@ def test_trace_id_no_context_header(self):
             trace_id = get_trace_id_from_flask()
             trace_id_returned = get_trace_id()
 
-        self.assertEqual(trace_id, _EMPTY_TRACE_ID)
-        self.assertEqual(trace_id_returned, _EMPTY_TRACE_ID)
+        self.assertEqual(trace_id, None)
+        self.assertEqual(trace_id_returned, None)
 
     def test_trace_id_valid_context_header(self):
         from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
         from google.cloud.logging.handlers._helpers import get_trace_id
 
-        FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
-        FLASK_TRACE_ID = 'testtraceidflask/testspanid'
+        flask_trace_header = 'X_CLOUD_TRACE_CONTEXT'
+        flask_trace_id = 'testtraceidflask/testspanid'
 
         with self.app.test_request_context(
                 path='/',
-                headers={FLASK_TRACE_HEADER:FLASK_TRACE_ID}):
+                headers={flask_trace_header:flask_trace_id}):
             trace_id = get_trace_id_from_flask()
             trace_id_returned = get_trace_id()
 
-        EXPECTED_TRACE_ID = 'testtraceidflask'
-        self.assertEqual(trace_id, EXPECTED_TRACE_ID)
+        expected_trace_id = 'testtraceidflask'
+        self.assertEqual(trace_id, expected_trace_id)
         self.assertEqual(trace_id, trace_id_returned)
 
 
@@ -73,48 +72,51 @@ def setUp(self):
             settings.configure()
         setup_test_environment()
 
+    def tearDown(self):
+        from django.test.utils import teardown_test_environment
+
+        teardown_test_environment()
+
     def test_trace_id_no_context_header(self):
-        import mock
         from django.test import RequestFactory
         from google.cloud.logging.handlers._helpers import get_trace_id_from_django
         from google.cloud.logging.handlers._helpers import get_trace_id
-        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
+        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+        from google.cloud.logging.handlers.middleware.request import _thread_locals
 
         request = RequestFactory().get('/')
 
-        with mock.patch(
-                'google.cloud.logging.handlers.middleware.RequestMiddleware.get_request',
-                return_value=request):
-            trace_id = get_trace_id_from_django()
-            trace_id_returned = get_trace_id()
+        middleware = RequestMiddleware()
+        middleware.process_request(request)
+        trace_id = get_trace_id_from_django()
+        trace_id_returned = get_trace_id()
 
-        self.assertEqual(trace_id, _EMPTY_TRACE_ID)
-        self.assertEqual(trace_id_returned, _EMPTY_TRACE_ID)
+        self.assertEqual(trace_id, None)
+        self.assertEqual(trace_id_returned, None)
+
+        _thread_locals.__dict__.clear()
 
     def test_trace_id_valid_context_header(self):
-        import mock
         from django.test import RequestFactory
         from google.cloud.logging.handlers._helpers import get_trace_id_from_django
         from google.cloud.logging.handlers._helpers import get_trace_id
+        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+        from google.cloud.logging.handlers.middleware.request import _thread_locals
 
-        DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
-        DJANGO_TRACE_ID = 'testtraceiddjango/testspanid'
+        django_trace_header = 'HTTP_X_CLOUD_TRACE_CONTEXT'
+        django_trace_id = 'testtraceiddjango/testspanid'
 
         request = RequestFactory().get(
             '/',
-            **{DJANGO_TRACE_HEADER:DJANGO_TRACE_ID})
+            **{django_trace_header:django_trace_id})
 
-        with mock.patch(
-                'google.cloud.logging.handlers.middleware.RequestMiddleware.get_request',
-                return_value=request):
-            trace_id = get_trace_id_from_django()
-            trace_id_returned = get_trace_id()
+        middleware = RequestMiddleware()
+        middleware.process_request(request)
+        trace_id = get_trace_id_from_django()
+        trace_id_returned = get_trace_id()
 
-        EXPECTED_TRACE_ID = 'testtraceiddjango'
-        self.assertEqual(trace_id, EXPECTED_TRACE_ID)
+        expected_trace_id = 'testtraceiddjango'
+        self.assertEqual(trace_id, expected_trace_id)
         self.assertEqual(trace_id, trace_id_returned)
 
-    def tearDown(self):
-        from django.test.utils import teardown_test_environment
-
-        teardown_test_environment()
+        _thread_locals.__dict__.clear()
diff --git a/logging/tests/unit/handlers/test_app_engine.py b/logging/tests/unit/handlers/test_app_engine.py
index 886dbbbb5584..ccdaf2992335 100644
--- a/logging/tests/unit/handlers/test_app_engine.py
+++ b/logging/tests/unit/handlers/test_app_engine.py
@@ -32,9 +32,7 @@ def test_constructor(self):
         from google.cloud.logging.handlers.app_engine import _GAE_PROJECT_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_SERVICE_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_VERSION_ENV
-        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
-
-        TRACE_ID_LABEL = 'appengine.googleapis.com/trace_id'
+        from google.cloud.logging.handlers.app_engine import _TRACE_ID_LABEL
 
         client = mock.Mock(project=self.PROJECT, spec=['project'])
 
@@ -47,7 +45,7 @@ def test_constructor(self):
         self.assertEqual(handler.resource.labels['project_id'], 'test_project')
         self.assertEqual(handler.resource.labels['module_id'], 'test_service')
         self.assertEqual(handler.resource.labels['version_id'], 'test_version')
-        self.assertEqual(handler.labels[TRACE_ID_LABEL], _EMPTY_TRACE_ID)
+        self.assertEqual(handler.labels, {})
 
     def test_emit(self):
         import mock

From 5cc798ffaf220a2b25b83020701cdfc82370eba2 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Tue, 30 May 2017 12:28:30 -0700
Subject: [PATCH 13/47] Address jon's comments

---
 logging/google/cloud/logging/handlers/_helpers.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 2c88f427f00b..00135d0fe243 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -80,10 +80,12 @@ def get_trace_id_from_django():
         return None
 
     try:
-        header = request.META[_DJANGO_TRACE_HEADER]
+        header = request.META.get(_DJANGO_TRACE_HEADER)
     except KeyError:
         return None
 
+    if not header:
+        return None
     trace_id = header.split('/')[0]
 
     return trace_id
@@ -102,4 +104,4 @@ def get_trace_id():
         if trace_id is not None:
             return trace_id
 
-    return trace_id
+    return None

From 6ef3f49a10a139d6e773214c8f0bf940660713a0 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 2 Jun 2017 00:28:10 -0700
Subject: [PATCH 14/47] Address all comments

---
 .../google/cloud/logging/handlers/_helpers.py | 14 ++---
 .../logging/handlers/middleware/request.py    |  6 +-
 logging/nox.py                                |  4 +-
 .../unit/handlers/middleware/test_request.py  | 18 +++---
 logging/tests/unit/handlers/test__helpers.py  | 56 +++++++++----------
 logging/tests/unit/handlers/test_handlers.py  |  4 +-
 .../transports/test_background_thread.py      |  3 +-
 .../unit/handlers/transports/test_sync.py     |  3 +-
 8 files changed, 58 insertions(+), 50 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 00135d0fe243..e5bdabe2e388 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -22,7 +22,7 @@
 except ImportError:
     flask = None
 
-from google.cloud.logging.handlers.middleware.request import _get_request
+from google.cloud.logging.handlers.middleware.request import _get_django_request
 
 _FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
 _DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
@@ -55,12 +55,12 @@ def get_trace_id_from_flask():
     :rtype: str
     :return: Trace_id in HTTP request headers.
     """
-    if not flask or not flask.request:
+    if flask is None or not flask.request:
         return None
 
     header = flask.request.headers.get(_FLASK_TRACE_HEADER)
 
-    if not header:
+    if header is None:
         return None
 
     trace_id = header.split('/')[0]
@@ -74,9 +74,9 @@ def get_trace_id_from_django():
     :rtype: str
     :return: Trace_id in HTTP request headers.
     """
-    request = _get_request()
+    request = _get_django_request()
 
-    if not request:
+    if request is None:
         return None
 
     try:
@@ -84,7 +84,7 @@ def get_trace_id_from_django():
     except KeyError:
         return None
 
-    if not header:
+    if header is None:
         return None
     trace_id = header.split('/')[0]
 
@@ -97,7 +97,7 @@ def get_trace_id():
     :rtype: str
     :returns: Trace_id in HTTP request headers.
     """
-    checkers = [get_trace_id_from_django, get_trace_id_from_flask]
+    checkers = (get_trace_id_from_django, get_trace_id_from_flask)
 
     for checker in checkers:
         trace_id = checker()
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index 9baf11f4dbbe..1acf7ffd9961 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -12,13 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from threading import local
+import threading
 
 
-_thread_locals = local()
+_thread_locals = threading.local()
 
 
-def _get_request():
+def _get_django_request():
     """Get Django request from thread local.
 
     :rtype: str
diff --git a/logging/nox.py b/logging/nox.py
index de975600fd04..fbbbec1958c1 100644
--- a/logging/nox.py
+++ b/logging/nox.py
@@ -31,7 +31,9 @@ def unit_tests(session, python_version):
     session.interpreter = 'python{}'.format(python_version)
 
     # Install all test dependencies, then install this package in-place.
-    session.install('mock', 'pytest', 'pytest-cov', 'flask', 'django', *LOCAL_DEPS)
+    session.install(
+        'mock', 'pytest', 'pytest-cov',
+        'flask', 'django', *LOCAL_DEPS)
     session.install('-e', '.')
 
     # Run py.test against the unit tests.
diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
index 349247805104..ab8c18d1aa0e 100644
--- a/logging/tests/unit/handlers/middleware/test_request.py
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -25,7 +25,8 @@ def _get_target_class(self):
     def _make_one(self, *args, **kw):
         return self._get_target_class()(*args, **kw)
 
-    def setUp(self):
+    @classmethod
+    def setUpClass(cls):
         from django.conf import settings
         from django.test.utils import setup_test_environment
 
@@ -33,16 +34,17 @@ def setUp(self):
             settings.configure()
         setup_test_environment()
 
-    def tearDown(self):
+    @classmethod
+    def tearDownClass(cls):
         from django.test.utils import teardown_test_environment
 
         teardown_test_environment()
 
-    def test_get_request(self):
+    def test_get_django_request(self):
         from django.test import RequestFactory
-        from google.cloud.logging.handlers.middleware.request import _get_request
+        from google.cloud.logging.handlers.middleware.request import _get_django_request
 
-        self.middleware = self._make_one()
-        self.request = RequestFactory().get('/')
-        self.middleware.process_request(self.request)
-        self.assertEqual(_get_request(), self.request)
+        middleware = self._make_one()
+        request = RequestFactory().get('/')
+        middleware.process_request(request)
+        self.assertEqual(_get_django_request(), request)
diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
index 634ceb26e8a6..59e56f34524b 100644
--- a/logging/tests/unit/handlers/test__helpers.py
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -15,9 +15,10 @@
 import unittest
 
 
-class TestFlaskTrace(unittest.TestCase):
+class Test_get_trace_id_from_flask(unittest.TestCase):
 
-    def create_app(self):
+    @staticmethod
+    def create_app():
         import flask
 
         app = flask.Flask(__name__)
@@ -29,40 +30,41 @@ def index():
         return app
 
     def setUp(self):
-        self.app = self.create_app()
+        self.app = Test_get_trace_id_from_flask.create_app()
 
     def test_trace_id_no_context_header(self):
-        from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
-        from google.cloud.logging.handlers._helpers import get_trace_id
+        from google.cloud.logging.handlers import _helpers
 
         with self.app.test_request_context(
                 path='/',
                 headers={}):
-            trace_id = get_trace_id_from_flask()
-            trace_id_returned = get_trace_id()
+            trace_id = _helpers.get_trace_id_from_flask()
+            trace_id_returned = _helpers.get_trace_id()
 
-        self.assertEqual(trace_id, None)
-        self.assertEqual(trace_id_returned, None)
+        self.assertIsNone(trace_id)
+        self.assertIsNone(trace_id_returned)
 
     def test_trace_id_valid_context_header(self):
         from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
         from google.cloud.logging.handlers._helpers import get_trace_id
 
         flask_trace_header = 'X_CLOUD_TRACE_CONTEXT'
-        flask_trace_id = 'testtraceidflask/testspanid'
+        expected_trace_id = 'testtraceidflask'
+        flask_trace_id = expected_trace_id + '/testspanid'
 
-        with self.app.test_request_context(
-                path='/',
-                headers={flask_trace_header:flask_trace_id}):
+        context = self.app.test_request_context(
+            path='/',
+            headers={flask_trace_header: flask_trace_id})
+
+        with context:
             trace_id = get_trace_id_from_flask()
             trace_id_returned = get_trace_id()
 
-        expected_trace_id = 'testtraceidflask'
         self.assertEqual(trace_id, expected_trace_id)
         self.assertEqual(trace_id, trace_id_returned)
 
 
-class TestDjangoTrace(unittest.TestCase):
+class Test_get_trace_id_from_django(unittest.TestCase):
 
     def setUp(self):
         from django.conf import settings
@@ -79,22 +81,20 @@ def tearDown(self):
 
     def test_trace_id_no_context_header(self):
         from django.test import RequestFactory
-        from google.cloud.logging.handlers._helpers import get_trace_id_from_django
-        from google.cloud.logging.handlers._helpers import get_trace_id
-        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
-        from google.cloud.logging.handlers.middleware.request import _thread_locals
+        from google.cloud.logging.handlers import _helpers
+        from google.cloud.logging.handlers.middleware import request
 
-        request = RequestFactory().get('/')
+        django_request = RequestFactory().get('/')
 
-        middleware = RequestMiddleware()
-        middleware.process_request(request)
-        trace_id = get_trace_id_from_django()
-        trace_id_returned = get_trace_id()
+        middleware = request.RequestMiddleware()
+        middleware.process_request(django_request)
+        trace_id = _helpers.get_trace_id_from_django()
+        trace_id_returned = _helpers.get_trace_id()
 
-        self.assertEqual(trace_id, None)
-        self.assertEqual(trace_id_returned, None)
+        self.assertIsNone(trace_id)
+        self.assertIsNone(trace_id_returned)
 
-        _thread_locals.__dict__.clear()
+        request._thread_locals.__dict__.clear()
 
     def test_trace_id_valid_context_header(self):
         from django.test import RequestFactory
@@ -108,7 +108,7 @@ def test_trace_id_valid_context_header(self):
 
         request = RequestFactory().get(
             '/',
-            **{django_trace_header:django_trace_id})
+            **{django_trace_header: django_trace_id})
 
         middleware = RequestMiddleware()
         middleware.process_request(request)
diff --git a/logging/tests/unit/handlers/test_handlers.py b/logging/tests/unit/handlers/test_handlers.py
index 5459a0c10b96..96823b2e906d 100644
--- a/logging/tests/unit/handlers/test_handlers.py
+++ b/logging/tests/unit/handlers/test_handlers.py
@@ -45,7 +45,9 @@ def test_emit(self):
                                    None, None)
         handler.emit(record)
 
-        self.assertEqual(handler.transport.send_called_with, (record, message, _GLOBAL_RESOURCE, None))
+        self.assertEqual(
+            handler.transport.send_called_with,
+            (record, message, _GLOBAL_RESOURCE, None))
 
 
 class TestSetupLogging(unittest.TestCase):
diff --git a/logging/tests/unit/handlers/transports/test_background_thread.py b/logging/tests/unit/handlers/transports/test_background_thread.py
index b9449ce56685..f6671273b53d 100644
--- a/logging/tests/unit/handlers/transports/test_background_thread.py
+++ b/logging/tests/unit/handlers/transports/test_background_thread.py
@@ -63,7 +63,8 @@ def test_send(self):
 
         transport.send(record, message, _GLOBAL_RESOURCE, None)
 
-        transport.worker.enqueue.assert_called_once_with(record, message, _GLOBAL_RESOURCE, None)
+        transport.worker.enqueue.assert_called_once_with(
+            record, message, _GLOBAL_RESOURCE, None)
 
     def test_flush(self):
         client = _Client(self.PROJECT)
diff --git a/logging/tests/unit/handlers/transports/test_sync.py b/logging/tests/unit/handlers/transports/test_sync.py
index e18920ce2167..01c15240f3b7 100644
--- a/logging/tests/unit/handlers/transports/test_sync.py
+++ b/logging/tests/unit/handlers/transports/test_sync.py
@@ -63,7 +63,8 @@ class _Logger(object):
     def __init__(self, name):
         self.name = name
 
-    def log_struct(self, message, severity=None, resource=_GLOBAL_RESOURCE, labels=None):
+    def log_struct(self, message, severity=None,
+                   resource=_GLOBAL_RESOURCE, labels=None):
         self.log_struct_called_with = (message, severity, resource, labels)
 
 

From 14c2545bc94fab6505305d6d4ccb4808c912a54d Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 2 Jun 2017 00:34:48 -0700
Subject: [PATCH 15/47] fix style

---
 logging/tests/unit/handlers/test__helpers.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
index 59e56f34524b..c50ce0044e85 100644
--- a/logging/tests/unit/handlers/test__helpers.py
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -104,7 +104,8 @@ def test_trace_id_valid_context_header(self):
         from google.cloud.logging.handlers.middleware.request import _thread_locals
 
         django_trace_header = 'HTTP_X_CLOUD_TRACE_CONTEXT'
-        django_trace_id = 'testtraceiddjango/testspanid'
+        expected_trace_id = 'testtraceiddjango'
+        django_trace_id = expected_trace_id + '/testspanid'
 
         request = RequestFactory().get(
             '/',
@@ -115,7 +116,6 @@ def test_trace_id_valid_context_header(self):
         trace_id = get_trace_id_from_django()
         trace_id_returned = get_trace_id()
 
-        expected_trace_id = 'testtraceiddjango'
         self.assertEqual(trace_id, expected_trace_id)
         self.assertEqual(trace_id, trace_id_returned)
 

From 199ada005c406f39924eb42e0329e66d5c023e42 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Mon, 22 May 2017 16:44:45 -0700
Subject: [PATCH 16/47] Send trace context with logs from web applications

---
 .../google/cloud/logging/handlers/_helpers.py | 39 ++++++++++++++++++
 .../cloud/logging/handlers/app_engine.py      | 18 ++++++++-
 .../google/cloud/logging/handlers/handlers.py | 12 +++++-
 .../logging/handlers/middleware/__init__.py   | 17 ++++++++
 .../logging/handlers/middleware/request.py    | 40 +++++++++++++++++++
 .../handlers/transports/background_thread.py  | 13 ++++--
 .../cloud/logging/handlers/transports/base.py |  5 ++-
 .../cloud/logging/handlers/transports/sync.py | 11 ++++-
 8 files changed, 146 insertions(+), 9 deletions(-)
 create mode 100644 logging/google/cloud/logging/handlers/middleware/__init__.py
 create mode 100644 logging/google/cloud/logging/handlers/middleware/request.py

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 81adcf0eb545..97b44d53ec19 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -17,6 +17,23 @@
 import math
 import json
 
+try:
+    import django
+except ImportError:
+    _USE_DJANGO = False
+else:
+    _USE_DJANGO = True
+
+try:
+    import flask
+except ImportError:
+    _USE_FLASK = False
+    flask = None
+else:
+    _USE_FLASK = True
+
+from google.cloud.logging.handlers.middleware.request import get_request
+
 
 def format_stackdriver_json(record, message):
     """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -37,3 +54,25 @@ def format_stackdriver_json(record, message):
     }
 
     return json.dumps(payload)
+
+
+def get_trace_id_from_request_header():
+    """Helper to get trace_id from web application request header.
+
+    :rtype: str
+    :returns: Trace_id in HTTP request headers.
+    """
+    if _USE_FLASK:
+        try:
+            trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]
+        except Exception:
+            trace_id = None
+    elif _USE_DJANGO:
+        try:
+            request = get_request()
+            trace_id = request.META['HTTP_X_CLOUD_TRACE_CONTEXT'].split('/')[0]
+        except Exception:
+            trace_id = None
+    else:
+        trace_id = None
+    return trace_id
diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index c7394f32262d..6860060e071f 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -20,6 +20,7 @@
 
 import os
 
+from google.cloud.logging.handlers._helpers import get_trace_id_from_request_header
 from google.cloud.logging.handlers.handlers import CloudLoggingHandler
 from google.cloud.logging.handlers.transports import BackgroundThreadTransport
 from google.cloud.logging.resource import Resource
@@ -50,7 +51,8 @@ def __init__(self, client,
             client,
             name=_DEFAULT_GAE_LOGGER_NAME,
             transport=transport,
-            resource=self.get_gae_resource())
+            resource=self.get_gae_resource(),
+            labels=self.get_gae_labels())
 
     def get_gae_resource(self):
         """Return the GAE resource using the environment variables.
@@ -67,3 +69,17 @@ def get_gae_resource(self):
             },
         )
         return gae_resource
+
+    def get_gae_labels(self):
+        """Return the labels for GAE app which includes trace_id.
+
+        :rtype: dict
+        :returns: Labels for GAE app.
+        """
+        trace_id = get_trace_id_from_request_header()
+        if trace_id is None:
+            trace_id = 'unknown'
+        gae_labels = {
+            'appengine.googleapis.com/trace_id': trace_id,
+        }
+        return gae_labels
\ No newline at end of file
diff --git a/logging/google/cloud/logging/handlers/handlers.py b/logging/google/cloud/logging/handlers/handlers.py
index 2269c2858f33..b45b4f593bc2 100644
--- a/logging/google/cloud/logging/handlers/handlers.py
+++ b/logging/google/cloud/logging/handlers/handlers.py
@@ -57,6 +57,9 @@ class CloudLoggingHandler(logging.StreamHandler):
     :param resource: (Optional) Monitored resource of the entry, defaults
                      to the global resource type.
 
+    :type labels: dict
+    :param labels: (Optional) Mapping of labels for the entry.
+
     Example:
 
     .. code-block:: python
@@ -79,12 +82,14 @@ class CloudLoggingHandler(logging.StreamHandler):
     def __init__(self, client,
                  name=DEFAULT_LOGGER_NAME,
                  transport=BackgroundThreadTransport,
-                 resource=_GLOBAL_RESOURCE):
+                 resource=_GLOBAL_RESOURCE,
+                 labels=None):
         super(CloudLoggingHandler, self).__init__()
         self.name = name
         self.client = client
         self.transport = transport(client, name)
         self.resource = resource
+        self.labels = labels
 
     def emit(self, record):
         """Actually log the specified logging record.
@@ -97,7 +102,10 @@ def emit(self, record):
         :param record: The record to be logged.
         """
         message = super(CloudLoggingHandler, self).format(record)
-        self.transport.send(record, message, resource=self.resource)
+        self.transport.send(record,
+                            message,
+                            resource=self.resource,
+                            labels=self.labels)
 
 
 def setup_logging(handler, excluded_loggers=EXCLUDED_LOGGER_DEFAULTS,
diff --git a/logging/google/cloud/logging/handlers/middleware/__init__.py b/logging/google/cloud/logging/handlers/middleware/__init__.py
new file mode 100644
index 000000000000..79c3abee7894
--- /dev/null
+++ b/logging/google/cloud/logging/handlers/middleware/__init__.py
@@ -0,0 +1,17 @@
+# Copyright 2016 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+
+__all__ = ['RequestMiddleware']
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
new file mode 100644
index 000000000000..0c6d1f46c5cd
--- /dev/null
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -0,0 +1,40 @@
+# Copyright 2016 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+try:
+    from threading import local
+except ImportError:
+    from django.utils._threading_local import local
+
+_thread_locals = local()
+
+
+def get_request():
+    """Get Django request from thread local.
+
+    :rtype: str
+    :returns: Django request.
+    """
+    return getattr(_thread_locals, 'request', None)
+
+class RequestMiddleware(object):
+    """Saves the request in thread local"""
+
+    def process_request(self, request):
+        """Called on each request, before Django decides which view to execute.
+
+        :type request: :class:`~django.http.request.HttpRequest`
+        :param request: Django http request.
+        """
+        _thread_locals.request = request
diff --git a/logging/google/cloud/logging/handlers/transports/background_thread.py b/logging/google/cloud/logging/handlers/transports/background_thread.py
index 010c06b36bc9..d889bed62626 100644
--- a/logging/google/cloud/logging/handlers/transports/background_thread.py
+++ b/logging/google/cloud/logging/handlers/transports/background_thread.py
@@ -203,7 +203,7 @@ def _main_thread_terminated(self):
         else:
             print('Failed to send %d pending logs.' % (self._queue.qsize(),))
 
-    def enqueue(self, record, message, resource=None):
+    def enqueue(self, record, message, resource=None, labels=None):
         """Queues a log entry to be written by the background thread.
 
         :type record: :class:`logging.LogRecord`
@@ -215,6 +215,9 @@ def enqueue(self, record, message, resource=None):
 
         :type resource: :class:`~google.cloud.logging.resource.Resource`
         :param resource: (Optional) Monitored resource of the entry
+
+        :type labels: dict
+        :param labels: (Optional) Mapping of labels for the entry.
         """
         self._queue.put_nowait({
             'info': {
@@ -223,6 +226,7 @@ def enqueue(self, record, message, resource=None):
             },
             'severity': record.levelname,
             'resource': resource,
+            'labels': labels,
         })
 
     def flush(self):
@@ -257,7 +261,7 @@ def __init__(self, client, name, grace_period=_DEFAULT_GRACE_PERIOD,
         self.worker = _Worker(logger)
         self.worker.start()
 
-    def send(self, record, message, resource=None):
+    def send(self, record, message, resource=None, labels=None):
         """Overrides Transport.send().
 
         :type record: :class:`logging.LogRecord`
@@ -269,8 +273,11 @@ def send(self, record, message, resource=None):
 
         :type resource: :class:`~google.cloud.logging.resource.Resource`
         :param resource: (Optional) Monitored resource of the entry.
+
+        :type labels: dict
+        :param labels: (Optional) Mapping of labels for the entry.
         """
-        self.worker.enqueue(record, message, resource=resource)
+        self.worker.enqueue(record, message, resource=resource, labels=labels)
 
     def flush(self):
         """Submit any pending log records."""
diff --git a/logging/google/cloud/logging/handlers/transports/base.py b/logging/google/cloud/logging/handlers/transports/base.py
index 21957021793f..7829201b1c98 100644
--- a/logging/google/cloud/logging/handlers/transports/base.py
+++ b/logging/google/cloud/logging/handlers/transports/base.py
@@ -22,7 +22,7 @@ class Transport(object):
     client and name object, and must override :meth:`send`.
     """
 
-    def send(self, record, message, resource=None):
+    def send(self, record, message, resource=None, labels=None):
         """Transport send to be implemented by subclasses.
 
         :type record: :class:`logging.LogRecord`
@@ -34,6 +34,9 @@ def send(self, record, message, resource=None):
 
         :type resource: :class:`~google.cloud.logging.resource.Resource`
         :param resource: (Optional) Monitored resource of the entry.
+
+        :type labels: dict
+        :param labels: (Optional) Mapping of labels for the entry.
         """
         raise NotImplementedError
 
diff --git a/logging/google/cloud/logging/handlers/transports/sync.py b/logging/google/cloud/logging/handlers/transports/sync.py
index 0dd6e0bd7e24..be70e60a14e1 100644
--- a/logging/google/cloud/logging/handlers/transports/sync.py
+++ b/logging/google/cloud/logging/handlers/transports/sync.py
@@ -29,7 +29,7 @@ class SyncTransport(Transport):
     def __init__(self, client, name):
         self.logger = client.logger(name)
 
-    def send(self, record, message, resource=None):
+    def send(self, record, message, resource=None, labels=None):
         """Overrides transport.send().
 
         :type record: :class:`logging.LogRecord`
@@ -38,8 +38,15 @@ def send(self, record, message, resource=None):
         :type message: str
         :param message: The message from the ``LogRecord`` after being
                         formatted by the associated log formatters.
+
+        :type resource: :class:`~google.cloud.logging.resource.Resource`
+        :param resource: (Optional) Monitored resource of the entry.
+
+        :type labels: dict
+        :param labels: (Optional) Mapping of labels for the entry.
         """
         info = {'message': message, 'python_logger': record.name}
         self.logger.log_struct(info,
                                severity=record.levelname,
-                               resource=resource)
+                               resource=resource,
+                               labels=labels)

From 425c8ef46ce7b255be3433218ec6c42021c32afc Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Mon, 22 May 2017 16:58:43 -0700
Subject: [PATCH 17/47] Fix style

---
 logging/google/cloud/logging/handlers/app_engine.py         | 2 +-
 logging/google/cloud/logging/handlers/middleware/request.py | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index 6860060e071f..ea4cc9245282 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -82,4 +82,4 @@ def get_gae_labels(self):
         gae_labels = {
             'appengine.googleapis.com/trace_id': trace_id,
         }
-        return gae_labels
\ No newline at end of file
+        return gae_labels
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index 0c6d1f46c5cd..a37a6af47035 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -28,6 +28,7 @@ def get_request():
     """
     return getattr(_thread_locals, 'request', None)
 
+
 class RequestMiddleware(object):
     """Saves the request in thread local"""
 

From 1047fd5612756a03c8bce4e9bb3229a729a4641d Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Tue, 23 May 2017 14:23:32 -0700
Subject: [PATCH 18/47] Improved code for web framework detection

---
 .../google/cloud/logging/handlers/_helpers.py | 37 ++++++++++++++-----
 1 file changed, 27 insertions(+), 10 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 97b44d53ec19..a1c697ba404c 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -16,24 +16,18 @@
 
 import math
 import json
-
-try:
-    import django
-except ImportError:
-    _USE_DJANGO = False
-else:
-    _USE_DJANGO = True
+import sys
 
 try:
     import flask
 except ImportError:
-    _USE_FLASK = False
     flask = None
-else:
-    _USE_FLASK = True
 
 from google.cloud.logging.handlers.middleware.request import get_request
 
+_USE_FLASK = False
+_USE_DJANGO = False
+
 
 def format_stackdriver_json(record, message):
     """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -56,12 +50,35 @@ def format_stackdriver_json(record, message):
     return json.dumps(payload)
 
 
+def detect_web_framework():
+    """Detect web framework used in this environment.
+
+    Detect which web framework is used by looking at the sys.modules.
+    If multiple or no supported web frameworks detected in the modules, then
+    print a warning message.
+    Set _USE_FLASK or _USE_DJANGO to True if one of them are detected.
+    """
+    modules = sys.modules
+    global _USE_FLASK, _USE_DJANGO
+
+    if 'flask' in modules and 'django' in modules:
+        print('Cannot determine, found multiple web frameworks.')
+    elif 'flask' in modules:
+        _USE_FLASK = True
+    elif 'django' in modules:
+        _USE_DJANGO = True
+    else:
+        print('No supported web framework found in the modules.')
+
+
 def get_trace_id_from_request_header():
     """Helper to get trace_id from web application request header.
 
     :rtype: str
     :returns: Trace_id in HTTP request headers.
     """
+    detect_web_framework()
+
     if _USE_FLASK:
         try:
             trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]

From 46012ebb2eb56306392fcfe84afbf8713588ec90 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Tue, 23 May 2017 14:28:01 -0700
Subject: [PATCH 19/47] Fix year

---
 logging/google/cloud/logging/handlers/middleware/__init__.py | 2 +-
 logging/google/cloud/logging/handlers/middleware/request.py  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/middleware/__init__.py b/logging/google/cloud/logging/handlers/middleware/__init__.py
index 79c3abee7894..c340235b8bdd 100644
--- a/logging/google/cloud/logging/handlers/middleware/__init__.py
+++ b/logging/google/cloud/logging/handlers/middleware/__init__.py
@@ -1,4 +1,4 @@
-# Copyright 2016 Google Inc. All Rights Reserved.
+# Copyright 2017 Google Inc. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index a37a6af47035..be5102487cc6 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -1,4 +1,4 @@
-# Copyright 2016 Google Inc. All Rights Reserved.
+# Copyright 2017 Google Inc. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.

From 43148bf40cd5bbae418f777d0e35c008e9d9834a Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Tue, 23 May 2017 14:45:28 -0700
Subject: [PATCH 20/47] Drop module level variables

---
 .../google/cloud/logging/handlers/_helpers.py | 22 ++++++++++---------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index a1c697ba404c..6bf0edf79d54 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -25,9 +25,6 @@
 
 from google.cloud.logging.handlers.middleware.request import get_request
 
-_USE_FLASK = False
-_USE_DJANGO = False
-
 
 def format_stackdriver_json(record, message):
     """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -56,19 +53,24 @@ def detect_web_framework():
     Detect which web framework is used by looking at the sys.modules.
     If multiple or no supported web frameworks detected in the modules, then
     print a warning message.
-    Set _USE_FLASK or _USE_DJANGO to True if one of them are detected.
+    Return the name of web framework detected if flask or django is found.
+    Return unknown if cannot determine.
+
+    :rtype: str
+    :returns: Web framework detected in this environment.
     """
     modules = sys.modules
-    global _USE_FLASK, _USE_DJANGO
+    web_framework = 'unknown'
 
     if 'flask' in modules and 'django' in modules:
         print('Cannot determine, found multiple web frameworks.')
     elif 'flask' in modules:
-        _USE_FLASK = True
+        web_framework = 'flask'
     elif 'django' in modules:
-        _USE_DJANGO = True
+        web_framework = 'django'
     else:
         print('No supported web framework found in the modules.')
+    return web_framework
 
 
 def get_trace_id_from_request_header():
@@ -77,14 +79,14 @@ def get_trace_id_from_request_header():
     :rtype: str
     :returns: Trace_id in HTTP request headers.
     """
-    detect_web_framework()
+    web_framework = detect_web_framework()
 
-    if _USE_FLASK:
+    if web_framework is 'flask':
         try:
             trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]
         except Exception:
             trace_id = None
-    elif _USE_DJANGO:
+    elif web_framework is 'django':
         try:
             request = get_request()
             trace_id = request.META['HTTP_X_CLOUD_TRACE_CONTEXT'].split('/')[0]

From de02a1de9cfad85ba35592935638eae816ec6b5d Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Thu, 25 May 2017 10:07:25 -0700
Subject: [PATCH 21/47] Address Jon's comments and add some unit tests (not
 complete yet)

---
 .../google/cloud/logging/handlers/_helpers.py | 66 ++++++++-----------
 .../cloud/logging/handlers/app_engine.py      |  4 +-
 .../google/cloud/logging/handlers/handlers.py |  9 +--
 .../logging/handlers/middleware/request.py    |  6 +-
 .../tests/unit/handlers/test_app_engine.py    | 11 +++-
 logging/tests/unit/handlers/test_handlers.py  |  6 +-
 .../transports/test_background_thread.py      |  8 +--
 .../unit/handlers/transports/test_sync.py     |  6 +-
 8 files changed, 56 insertions(+), 60 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 6bf0edf79d54..0af7a53de476 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -16,7 +16,6 @@
 
 import math
 import json
-import sys
 
 try:
     import flask
@@ -47,51 +46,44 @@ def format_stackdriver_json(record, message):
     return json.dumps(payload)
 
 
-def detect_web_framework():
-    """Detect web framework used in this environment.
-
-    Detect which web framework is used by looking at the sys.modules.
-    If multiple or no supported web frameworks detected in the modules, then
-    print a warning message.
-    Return the name of web framework detected if flask or django is found.
-    Return unknown if cannot determine.
+def get_trace_id_from_flask():
+    """Get trace_id from flask request headers.
 
     :rtype: str
-    :returns: Web framework detected in this environment.
+    :return: Trace_id in HTTP request headers.
     """
-    modules = sys.modules
-    web_framework = 'unknown'
+    try:
+        trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]
+    except Exception:
+        trace_id = None
+    return trace_id
 
-    if 'flask' in modules and 'django' in modules:
-        print('Cannot determine, found multiple web frameworks.')
-    elif 'flask' in modules:
-        web_framework = 'flask'
-    elif 'django' in modules:
-        web_framework = 'django'
-    else:
-        print('No supported web framework found in the modules.')
-    return web_framework
+
+def get_trace_id_from_django():
+    """Get trace_id from django request headers.
+
+    :rtype: str
+    :return: Trace_id in HTTP request headers.
+    """
+    try:
+        request = get_request()
+        trace_id = request.META['HTTP_X_CLOUD_TRACE_CONTEXT'].split('/')[0]
+    except Exception:
+        trace_id = None
+    return trace_id
 
 
-def get_trace_id_from_request_header():
+def get_trace_id():
     """Helper to get trace_id from web application request header.
 
     :rtype: str
     :returns: Trace_id in HTTP request headers.
     """
-    web_framework = detect_web_framework()
-
-    if web_framework is 'flask':
-        try:
-            trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]
-        except Exception:
-            trace_id = None
-    elif web_framework is 'django':
-        try:
-            request = get_request()
-            trace_id = request.META['HTTP_X_CLOUD_TRACE_CONTEXT'].split('/')[0]
-        except Exception:
-            trace_id = None
-    else:
-        trace_id = None
+    checkers = [get_trace_id_from_django, get_trace_id_from_flask]
+
+    for checker in checkers:
+        trace_id = checker()
+        if trace_id is not None:
+            return trace_id
+
     return trace_id
diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index ea4cc9245282..7bf4790e0603 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -20,7 +20,7 @@
 
 import os
 
-from google.cloud.logging.handlers._helpers import get_trace_id_from_request_header
+from google.cloud.logging.handlers._helpers import get_trace_id
 from google.cloud.logging.handlers.handlers import CloudLoggingHandler
 from google.cloud.logging.handlers.transports import BackgroundThreadTransport
 from google.cloud.logging.resource import Resource
@@ -76,7 +76,7 @@ def get_gae_labels(self):
         :rtype: dict
         :returns: Labels for GAE app.
         """
-        trace_id = get_trace_id_from_request_header()
+        trace_id = get_trace_id()
         if trace_id is None:
             trace_id = 'unknown'
         gae_labels = {
diff --git a/logging/google/cloud/logging/handlers/handlers.py b/logging/google/cloud/logging/handlers/handlers.py
index b45b4f593bc2..26343ec9f9c5 100644
--- a/logging/google/cloud/logging/handlers/handlers.py
+++ b/logging/google/cloud/logging/handlers/handlers.py
@@ -102,10 +102,11 @@ def emit(self, record):
         :param record: The record to be logged.
         """
         message = super(CloudLoggingHandler, self).format(record)
-        self.transport.send(record,
-                            message,
-                            resource=self.resource,
-                            labels=self.labels)
+        self.transport.send(
+            record,
+            message,
+            resource=self.resource,
+            labels=self.labels)
 
 
 def setup_logging(handler, excluded_loggers=EXCLUDED_LOGGER_DEFAULTS,
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index be5102487cc6..92bfd4369b00 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -12,10 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-try:
-    from threading import local
-except ImportError:
-    from django.utils._threading_local import local
+from threading import local
+
 
 _thread_locals = local()
 
diff --git a/logging/tests/unit/handlers/test_app_engine.py b/logging/tests/unit/handlers/test_app_engine.py
index c39328593f7a..99f5ea93625a 100644
--- a/logging/tests/unit/handlers/test_app_engine.py
+++ b/logging/tests/unit/handlers/test_app_engine.py
@@ -34,6 +34,7 @@ def test_constructor(self):
         from google.cloud.logging.handlers.app_engine import _GAE_VERSION_ENV
 
         client = mock.Mock(project=self.PROJECT, spec=['project'])
+
         with mock.patch('os.environ', new={_GAE_PROJECT_ENV: 'test_project',
                                            _GAE_SERVICE_ENV: 'test_service',
                                            _GAE_VERSION_ENV: 'test_version'}):
@@ -43,6 +44,7 @@ def test_constructor(self):
         self.assertEqual(handler.resource.labels['project_id'], 'test_project')
         self.assertEqual(handler.resource.labels['module_id'], 'test_service')
         self.assertEqual(handler.resource.labels['version_id'], 'test_version')
+        self.assertEqual(handler.labels['appengine.googleapis.com/trace_id'], 'unknown')
 
     def test_emit(self):
         import mock
@@ -50,6 +52,7 @@ def test_emit(self):
         client = mock.Mock(project=self.PROJECT, spec=['project'])
         handler = self._make_one(client, transport=_Transport)
         gae_resource = handler.get_gae_resource()
+        gae_labels = handler.get_gae_labels()
         logname = 'app'
         message = 'hello world'
         record = logging.LogRecord(logname, logging, None, None, message,
@@ -58,7 +61,9 @@ def test_emit(self):
 
         self.assertIs(handler.transport.client, client)
         self.assertEqual(handler.transport.name, logname)
-        self.assertEqual(handler.transport.send_called_with, (record, message, gae_resource))
+        self.assertEqual(
+            handler.transport.send_called_with,
+            (record, message, gae_resource, gae_labels))
 
 
 class _Transport(object):
@@ -67,5 +72,5 @@ def __init__(self, client, name):
         self.client = client
         self.name = name
 
-    def send(self, record, message, resource):
-        self.send_called_with = (record, message, resource)
+    def send(self, record, message, resource, labels):
+        self.send_called_with = (record, message, resource, labels)
diff --git a/logging/tests/unit/handlers/test_handlers.py b/logging/tests/unit/handlers/test_handlers.py
index 05dc87631478..5459a0c10b96 100644
--- a/logging/tests/unit/handlers/test_handlers.py
+++ b/logging/tests/unit/handlers/test_handlers.py
@@ -45,7 +45,7 @@ def test_emit(self):
                                    None, None)
         handler.emit(record)
 
-        self.assertEqual(handler.transport.send_called_with, (record, message, _GLOBAL_RESOURCE))
+        self.assertEqual(handler.transport.send_called_with, (record, message, _GLOBAL_RESOURCE, None))
 
 
 class TestSetupLogging(unittest.TestCase):
@@ -110,5 +110,5 @@ class _Transport(object):
     def __init__(self, client, name):
         pass
 
-    def send(self, record, message, resource):
-        self.send_called_with = (record, message, resource)
+    def send(self, record, message, resource, labels=None):
+        self.send_called_with = (record, message, resource, labels)
diff --git a/logging/tests/unit/handlers/transports/test_background_thread.py b/logging/tests/unit/handlers/transports/test_background_thread.py
index 3e3378dcd361..b9449ce56685 100644
--- a/logging/tests/unit/handlers/transports/test_background_thread.py
+++ b/logging/tests/unit/handlers/transports/test_background_thread.py
@@ -61,9 +61,9 @@ def test_send(self):
             python_logger_name, logging.INFO,
             None, None, message, None, None)
 
-        transport.send(record, message, _GLOBAL_RESOURCE)
+        transport.send(record, message, _GLOBAL_RESOURCE, None)
 
-        transport.worker.enqueue.assert_called_once_with(record, message, _GLOBAL_RESOURCE)
+        transport.worker.enqueue.assert_called_once_with(record, message, _GLOBAL_RESOURCE, None)
 
     def test_flush(self):
         client = _Client(self.PROJECT)
@@ -287,13 +287,13 @@ def __init__(self):
         self.commit_called = False
         self.commit_count = None
 
-    def log_struct(self, info, severity=logging.INFO, resource=None):
+    def log_struct(self, info, severity=logging.INFO, resource=None, labels=None):
         from google.cloud.logging.logger import _GLOBAL_RESOURCE
 
         assert resource is None
         resource = _GLOBAL_RESOURCE
 
-        self.log_struct_called_with = (info, severity, resource)
+        self.log_struct_called_with = (info, severity, resource, labels)
         self.entries.append(info)
 
     def commit(self):
diff --git a/logging/tests/unit/handlers/transports/test_sync.py b/logging/tests/unit/handlers/transports/test_sync.py
index 475ecc9c6a71..e18920ce2167 100644
--- a/logging/tests/unit/handlers/transports/test_sync.py
+++ b/logging/tests/unit/handlers/transports/test_sync.py
@@ -52,7 +52,7 @@ def test_send(self):
             'message': message,
             'python_logger': python_logger_name,
         }
-        EXPECTED_SENT = (EXPECTED_STRUCT, 'INFO', _GLOBAL_RESOURCE)
+        EXPECTED_SENT = (EXPECTED_STRUCT, 'INFO', _GLOBAL_RESOURCE, None)
         self.assertEqual(
             transport.logger.log_struct_called_with, EXPECTED_SENT)
 
@@ -63,8 +63,8 @@ class _Logger(object):
     def __init__(self, name):
         self.name = name
 
-    def log_struct(self, message, severity=None, resource=_GLOBAL_RESOURCE):
-        self.log_struct_called_with = (message, severity, resource)
+    def log_struct(self, message, severity=None, resource=_GLOBAL_RESOURCE, labels=None):
+        self.log_struct_called_with = (message, severity, resource, labels)
 
 
 class _Client(object):

From ffb57c40a1e4426ca3f8001d6bc2d393321eec73 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Thu, 25 May 2017 10:45:36 -0700
Subject: [PATCH 22/47] Fix stuff

---
 .../google/cloud/logging/handlers/_helpers.py | 35 ++++++++++++++-----
 .../logging/handlers/middleware/request.py    | 17 +++++----
 .../tests/unit/handlers/test_app_engine.py    |  4 ++-
 3 files changed, 37 insertions(+), 19 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 0af7a53de476..ca94e17ebb92 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -22,7 +22,10 @@
 except ImportError:
     flask = None
 
-from google.cloud.logging.handlers.middleware.request import get_request
+from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+
+_FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
+_DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
 
 
 def format_stackdriver_json(record, message):
@@ -52,10 +55,16 @@ def get_trace_id_from_flask():
     :rtype: str
     :return: Trace_id in HTTP request headers.
     """
-    try:
-        trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]
-    except Exception:
-        trace_id = None
+    if not flask or not flask.request:
+        return None
+
+    header = flask.request.headers.get(_FLASK_TRACE_HEADER)
+
+    if not header:
+        return None
+
+    trace_id = header.split('/')[0]
+
     return trace_id
 
 
@@ -65,11 +74,19 @@ def get_trace_id_from_django():
     :rtype: str
     :return: Trace_id in HTTP request headers.
     """
+    request_middleware = RequestMiddleware()
+    request = request_middleware.get_request()
+
+    if not request:
+        return None
+
     try:
-        request = get_request()
-        trace_id = request.META['HTTP_X_CLOUD_TRACE_CONTEXT'].split('/')[0]
-    except Exception:
-        trace_id = None
+        header = request.META[_DJANGO_TRACE_HEADER]
+    except KeyError:
+        return None
+
+    trace_id = header.split('/')[0]
+
     return trace_id
 
 
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index 92bfd4369b00..7e0e89f6aa39 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -18,15 +18,6 @@
 _thread_locals = local()
 
 
-def get_request():
-    """Get Django request from thread local.
-
-    :rtype: str
-    :returns: Django request.
-    """
-    return getattr(_thread_locals, 'request', None)
-
-
 class RequestMiddleware(object):
     """Saves the request in thread local"""
 
@@ -37,3 +28,11 @@ def process_request(self, request):
         :param request: Django http request.
         """
         _thread_locals.request = request
+
+    def get_request(self):
+        """Get Django request from thread local.
+
+        :rtype: str
+        :returns: Django request.
+        """
+        return getattr(_thread_locals, 'request', None)
diff --git a/logging/tests/unit/handlers/test_app_engine.py b/logging/tests/unit/handlers/test_app_engine.py
index 99f5ea93625a..0f8ace3a95e7 100644
--- a/logging/tests/unit/handlers/test_app_engine.py
+++ b/logging/tests/unit/handlers/test_app_engine.py
@@ -33,6 +33,8 @@ def test_constructor(self):
         from google.cloud.logging.handlers.app_engine import _GAE_SERVICE_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_VERSION_ENV
 
+        TRACE_ID_LABEL = 'appengine.googleapis.com/trace_id'
+
         client = mock.Mock(project=self.PROJECT, spec=['project'])
 
         with mock.patch('os.environ', new={_GAE_PROJECT_ENV: 'test_project',
@@ -44,7 +46,7 @@ def test_constructor(self):
         self.assertEqual(handler.resource.labels['project_id'], 'test_project')
         self.assertEqual(handler.resource.labels['module_id'], 'test_service')
         self.assertEqual(handler.resource.labels['version_id'], 'test_version')
-        self.assertEqual(handler.labels['appengine.googleapis.com/trace_id'], 'unknown')
+        self.assertEqual(handler.labels[TRACE_ID_LABEL], 'unknown')
 
     def test_emit(self):
         import mock

From 8fd8f316fa29d26eb097642a94d1905db5373745 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Thu, 25 May 2017 14:54:23 -0700
Subject: [PATCH 23/47] Add unit test for flask and some refactor

---
 .../google/cloud/logging/handlers/_helpers.py | 12 ++--
 .../cloud/logging/handlers/app_engine.py      |  2 -
 logging/nox.py                                |  2 +-
 logging/tests/unit/handlers/test__helpers.py  | 57 +++++++++++++++++++
 .../tests/unit/handlers/test_app_engine.py    |  3 +-
 5 files changed, 67 insertions(+), 9 deletions(-)
 create mode 100644 logging/tests/unit/handlers/test__helpers.py

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index ca94e17ebb92..17caf76e4aa9 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -27,6 +27,8 @@
 _FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
 _DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
 
+_EMPTY_TRACE_ID = 'None'
+
 
 def format_stackdriver_json(record, message):
     """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -56,12 +58,12 @@ def get_trace_id_from_flask():
     :return: Trace_id in HTTP request headers.
     """
     if not flask or not flask.request:
-        return None
+        return _EMPTY_TRACE_ID
 
     header = flask.request.headers.get(_FLASK_TRACE_HEADER)
 
     if not header:
-        return None
+        return _EMPTY_TRACE_ID
 
     trace_id = header.split('/')[0]
 
@@ -78,12 +80,12 @@ def get_trace_id_from_django():
     request = request_middleware.get_request()
 
     if not request:
-        return None
+        return _EMPTY_TRACE_ID
 
     try:
         header = request.META[_DJANGO_TRACE_HEADER]
     except KeyError:
-        return None
+        return _EMPTY_TRACE_ID
 
     trace_id = header.split('/')[0]
 
@@ -100,7 +102,7 @@ def get_trace_id():
 
     for checker in checkers:
         trace_id = checker()
-        if trace_id is not None:
+        if trace_id is not _EMPTY_TRACE_ID:
             return trace_id
 
     return trace_id
diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index 7bf4790e0603..daa48132e246 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -77,8 +77,6 @@ def get_gae_labels(self):
         :returns: Labels for GAE app.
         """
         trace_id = get_trace_id()
-        if trace_id is None:
-            trace_id = 'unknown'
         gae_labels = {
             'appengine.googleapis.com/trace_id': trace_id,
         }
diff --git a/logging/nox.py b/logging/nox.py
index 5d4751a955a5..11d484b232e7 100644
--- a/logging/nox.py
+++ b/logging/nox.py
@@ -31,7 +31,7 @@ def unit_tests(session, python_version):
     session.interpreter = 'python{}'.format(python_version)
 
     # Install all test dependencies, then install this package in-place.
-    session.install('mock', 'pytest', 'pytest-cov', *LOCAL_DEPS)
+    session.install('mock', 'pytest', 'pytest-cov', 'flask', *LOCAL_DEPS)
     session.install('-e', '.')
 
     # Run py.test against the unit tests.
diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
new file mode 100644
index 000000000000..db9d51d27920
--- /dev/null
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -0,0 +1,57 @@
+# Copyright 2017 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+
+
+class TestFlaskTrace(unittest.TestCase):
+
+    def create_app(self):
+        import flask
+
+        app = flask.Flask(__name__)
+
+        @app.route('/')
+        def index():
+            return 'test flask trace'
+
+        return app
+
+    def setUp(self):
+        self.app = self.create_app()
+
+    def test_trace_id_no_context_header(self):
+        from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
+        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
+
+        with self.app.test_request_context(
+                path='/',
+                headers={}):
+            trace_id = get_trace_id_from_flask()
+
+        self.assertEqual(trace_id, _EMPTY_TRACE_ID)
+
+    def test_trace_id_valid_context_header(self):
+        from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
+
+        FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
+        FLASK_TRACE_ID = 'testtraceid/testspanid'
+
+        with self.app.test_request_context(
+                path='/',
+                headers={FLASK_TRACE_HEADER:FLASK_TRACE_ID}):
+            trace_id = get_trace_id_from_flask()
+
+        EXPECTED_TRACE_ID = 'testtraceid'
+        self.assertEqual(trace_id, EXPECTED_TRACE_ID)
diff --git a/logging/tests/unit/handlers/test_app_engine.py b/logging/tests/unit/handlers/test_app_engine.py
index 0f8ace3a95e7..886dbbbb5584 100644
--- a/logging/tests/unit/handlers/test_app_engine.py
+++ b/logging/tests/unit/handlers/test_app_engine.py
@@ -32,6 +32,7 @@ def test_constructor(self):
         from google.cloud.logging.handlers.app_engine import _GAE_PROJECT_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_SERVICE_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_VERSION_ENV
+        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
 
         TRACE_ID_LABEL = 'appengine.googleapis.com/trace_id'
 
@@ -46,7 +47,7 @@ def test_constructor(self):
         self.assertEqual(handler.resource.labels['project_id'], 'test_project')
         self.assertEqual(handler.resource.labels['module_id'], 'test_service')
         self.assertEqual(handler.resource.labels['version_id'], 'test_version')
-        self.assertEqual(handler.labels[TRACE_ID_LABEL], 'unknown')
+        self.assertEqual(handler.labels[TRACE_ID_LABEL], _EMPTY_TRACE_ID)
 
     def test_emit(self):
         import mock

From 44800270d6dcf141d1c04da65bbba1ff3ddbc109 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 26 May 2017 10:20:56 -0700
Subject: [PATCH 24/47] Add unit test for middleware

---
 logging/nox.py                                |  2 +-
 .../unit/handlers/middleware/test_request.py  | 39 +++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)
 create mode 100644 logging/tests/unit/handlers/middleware/test_request.py

diff --git a/logging/nox.py b/logging/nox.py
index 11d484b232e7..de975600fd04 100644
--- a/logging/nox.py
+++ b/logging/nox.py
@@ -31,7 +31,7 @@ def unit_tests(session, python_version):
     session.interpreter = 'python{}'.format(python_version)
 
     # Install all test dependencies, then install this package in-place.
-    session.install('mock', 'pytest', 'pytest-cov', 'flask', *LOCAL_DEPS)
+    session.install('mock', 'pytest', 'pytest-cov', 'flask', 'django', *LOCAL_DEPS)
     session.install('-e', '.')
 
     # Run py.test against the unit tests.
diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
new file mode 100644
index 000000000000..ad784b45c48e
--- /dev/null
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -0,0 +1,39 @@
+# Copyright 2017 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+
+
+class TestRequestMiddleware(unittest.TestCase):
+
+    def _get_target_class(self):
+        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+
+        return RequestMiddleware
+
+    def _make_one(self, *args, **kw):
+        return self._get_target_class()(*args, **kw)
+
+    def test_get_request(self):
+        from django.conf import settings
+        from django.test.utils import setup_test_environment
+        from django.test import RequestFactory
+
+        settings.configure()
+        setup_test_environment()
+
+        self.middleware = self._make_one()
+        self.request = RequestFactory().get('/')
+        self.middleware.process_request(self.request)
+        self.assertEqual(self.middleware.get_request(), self.request)

From ad00bdb98131f71396dd05c9b219211892efe481 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 26 May 2017 11:25:41 -0700
Subject: [PATCH 25/47] Add unit test for django

---
 .../unit/handlers/middleware/test_request.py  | 15 ++++-
 logging/tests/unit/handlers/test__helpers.py  | 67 ++++++++++++++++++-
 2 files changed, 77 insertions(+), 5 deletions(-)

diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
index ad784b45c48e..5b6dfca8dc67 100644
--- a/logging/tests/unit/handlers/middleware/test_request.py
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -25,15 +25,24 @@ def _get_target_class(self):
     def _make_one(self, *args, **kw):
         return self._get_target_class()(*args, **kw)
 
-    def test_get_request(self):
+    def setUp(self):
         from django.conf import settings
         from django.test.utils import setup_test_environment
-        from django.test import RequestFactory
 
-        settings.configure()
+        if not settings.configured:
+            settings.configure()
         setup_test_environment()
 
+    def test_get_request(self):
+        from django.test import RequestFactory
+
         self.middleware = self._make_one()
         self.request = RequestFactory().get('/')
         self.middleware.process_request(self.request)
         self.assertEqual(self.middleware.get_request(), self.request)
+
+
+    def tearDown(self):
+        from django.test.utils import teardown_test_environment
+
+        teardown_test_environment()
diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
index db9d51d27920..3d023dd8f9cf 100644
--- a/logging/tests/unit/handlers/test__helpers.py
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -33,25 +33,88 @@ def setUp(self):
 
     def test_trace_id_no_context_header(self):
         from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
+        from google.cloud.logging.handlers._helpers import get_trace_id
         from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
 
         with self.app.test_request_context(
                 path='/',
                 headers={}):
             trace_id = get_trace_id_from_flask()
+            trace_id_returned = get_trace_id()
 
         self.assertEqual(trace_id, _EMPTY_TRACE_ID)
+        self.assertEqual(trace_id_returned, _EMPTY_TRACE_ID)
 
     def test_trace_id_valid_context_header(self):
         from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
+        from google.cloud.logging.handlers._helpers import get_trace_id
 
         FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
-        FLASK_TRACE_ID = 'testtraceid/testspanid'
+        FLASK_TRACE_ID = 'testtraceidflask/testspanid'
 
         with self.app.test_request_context(
                 path='/',
                 headers={FLASK_TRACE_HEADER:FLASK_TRACE_ID}):
             trace_id = get_trace_id_from_flask()
+            trace_id_returned = get_trace_id()
 
-        EXPECTED_TRACE_ID = 'testtraceid'
+        EXPECTED_TRACE_ID = 'testtraceidflask'
         self.assertEqual(trace_id, EXPECTED_TRACE_ID)
+        self.assertEqual(trace_id, trace_id_returned)
+
+
+class TestDjangoTrace(unittest.TestCase):
+
+    def setUp(self):
+        from django.conf import settings
+        from django.test.utils import setup_test_environment
+
+        if not settings.configured:
+            settings.configure()
+        setup_test_environment()
+
+    def test_trace_id_no_context_header(self):
+        import mock
+        from django.test import RequestFactory
+        from google.cloud.logging.handlers._helpers import get_trace_id_from_django
+        from google.cloud.logging.handlers._helpers import get_trace_id
+        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
+
+        request = RequestFactory().get('/')
+
+        with mock.patch(
+                'google.cloud.logging.handlers.middleware.RequestMiddleware.get_request',
+                return_value=request):
+            trace_id = get_trace_id_from_django()
+            trace_id_returned = get_trace_id()
+
+        self.assertEqual(trace_id, _EMPTY_TRACE_ID)
+        self.assertEqual(trace_id_returned, _EMPTY_TRACE_ID)
+
+    def test_trace_id_valid_context_header(self):
+        import mock
+        from django.test import RequestFactory
+        from google.cloud.logging.handlers._helpers import get_trace_id_from_django
+        from google.cloud.logging.handlers._helpers import get_trace_id
+
+        DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
+        DJANGO_TRACE_ID = 'testtraceiddjango/testspanid'
+
+        request = RequestFactory().get(
+            '/',
+            **{DJANGO_TRACE_HEADER:DJANGO_TRACE_ID})
+
+        with mock.patch(
+                'google.cloud.logging.handlers.middleware.RequestMiddleware.get_request',
+                return_value=request):
+            trace_id = get_trace_id_from_django()
+            trace_id_returned = get_trace_id()
+
+        EXPECTED_TRACE_ID = 'testtraceiddjango'
+        self.assertEqual(trace_id, EXPECTED_TRACE_ID)
+        self.assertEqual(trace_id, trace_id_returned)
+
+    def tearDown(self):
+        from django.test.utils import teardown_test_environment
+
+        teardown_test_environment()

From 8ed81ad0b6f4afcc0cb7b3d89cb26693fb137d4b Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 26 May 2017 11:29:54 -0700
Subject: [PATCH 26/47] Fix style

---
 logging/tests/unit/handlers/middleware/test_request.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
index 5b6dfca8dc67..0aa950263f5d 100644
--- a/logging/tests/unit/handlers/middleware/test_request.py
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -41,7 +41,6 @@ def test_get_request(self):
         self.middleware.process_request(self.request)
         self.assertEqual(self.middleware.get_request(), self.request)
 
-
     def tearDown(self):
         from django.test.utils import teardown_test_environment
 

From a6b25bbdaf5da742e90c27d8118a7df493685a11 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 26 May 2017 14:38:45 -0700
Subject: [PATCH 27/47] Address jon's comments

---
 .../google/cloud/logging/handlers/_helpers.py | 17 ++---
 .../cloud/logging/handlers/app_engine.py      | 10 ++-
 .../logging/handlers/middleware/request.py    | 17 ++---
 .../unit/handlers/middleware/test_request.py  | 13 ++--
 logging/tests/unit/handlers/test__helpers.py  | 66 ++++++++++---------
 .../tests/unit/handlers/test_app_engine.py    |  6 +-
 6 files changed, 66 insertions(+), 63 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 17caf76e4aa9..2c88f427f00b 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -22,13 +22,11 @@
 except ImportError:
     flask = None
 
-from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+from google.cloud.logging.handlers.middleware.request import _get_request
 
 _FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
 _DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
 
-_EMPTY_TRACE_ID = 'None'
-
 
 def format_stackdriver_json(record, message):
     """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -58,12 +56,12 @@ def get_trace_id_from_flask():
     :return: Trace_id in HTTP request headers.
     """
     if not flask or not flask.request:
-        return _EMPTY_TRACE_ID
+        return None
 
     header = flask.request.headers.get(_FLASK_TRACE_HEADER)
 
     if not header:
-        return _EMPTY_TRACE_ID
+        return None
 
     trace_id = header.split('/')[0]
 
@@ -76,16 +74,15 @@ def get_trace_id_from_django():
     :rtype: str
     :return: Trace_id in HTTP request headers.
     """
-    request_middleware = RequestMiddleware()
-    request = request_middleware.get_request()
+    request = _get_request()
 
     if not request:
-        return _EMPTY_TRACE_ID
+        return None
 
     try:
         header = request.META[_DJANGO_TRACE_HEADER]
     except KeyError:
-        return _EMPTY_TRACE_ID
+        return None
 
     trace_id = header.split('/')[0]
 
@@ -102,7 +99,7 @@ def get_trace_id():
 
     for checker in checkers:
         trace_id = checker()
-        if trace_id is not _EMPTY_TRACE_ID:
+        if trace_id is not None:
             return trace_id
 
     return trace_id
diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index daa48132e246..f8b12c44a42e 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -31,6 +31,8 @@
 _GAE_SERVICE_ENV = 'GAE_SERVICE'
 _GAE_VERSION_ENV = 'GAE_VERSION'
 
+_TRACE_ID_LABEL = 'appengine.googleapis.com/trace_id'
+
 
 class AppEngineHandler(CloudLoggingHandler):
     """A logging handler that sends App Engine-formatted logs to Stackdriver.
@@ -76,8 +78,10 @@ def get_gae_labels(self):
         :rtype: dict
         :returns: Labels for GAE app.
         """
+        gae_labels = {}
+
         trace_id = get_trace_id()
-        gae_labels = {
-            'appengine.googleapis.com/trace_id': trace_id,
-        }
+        if trace_id is not None:
+            gae_labels[_TRACE_ID_LABEL] = trace_id
+
         return gae_labels
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index 7e0e89f6aa39..9baf11f4dbbe 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -18,6 +18,15 @@
 _thread_locals = local()
 
 
+def _get_request():
+    """Get Django request from thread local.
+
+    :rtype: str
+    :returns: Django request.
+    """
+    return getattr(_thread_locals, 'request', None)
+
+
 class RequestMiddleware(object):
     """Saves the request in thread local"""
 
@@ -28,11 +37,3 @@ def process_request(self, request):
         :param request: Django http request.
         """
         _thread_locals.request = request
-
-    def get_request(self):
-        """Get Django request from thread local.
-
-        :rtype: str
-        :returns: Django request.
-        """
-        return getattr(_thread_locals, 'request', None)
diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
index 0aa950263f5d..349247805104 100644
--- a/logging/tests/unit/handlers/middleware/test_request.py
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -33,15 +33,16 @@ def setUp(self):
             settings.configure()
         setup_test_environment()
 
+    def tearDown(self):
+        from django.test.utils import teardown_test_environment
+
+        teardown_test_environment()
+
     def test_get_request(self):
         from django.test import RequestFactory
+        from google.cloud.logging.handlers.middleware.request import _get_request
 
         self.middleware = self._make_one()
         self.request = RequestFactory().get('/')
         self.middleware.process_request(self.request)
-        self.assertEqual(self.middleware.get_request(), self.request)
-
-    def tearDown(self):
-        from django.test.utils import teardown_test_environment
-
-        teardown_test_environment()
+        self.assertEqual(_get_request(), self.request)
diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
index 3d023dd8f9cf..634ceb26e8a6 100644
--- a/logging/tests/unit/handlers/test__helpers.py
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -34,7 +34,6 @@ def setUp(self):
     def test_trace_id_no_context_header(self):
         from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
         from google.cloud.logging.handlers._helpers import get_trace_id
-        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
 
         with self.app.test_request_context(
                 path='/',
@@ -42,24 +41,24 @@ def test_trace_id_no_context_header(self):
             trace_id = get_trace_id_from_flask()
             trace_id_returned = get_trace_id()
 
-        self.assertEqual(trace_id, _EMPTY_TRACE_ID)
-        self.assertEqual(trace_id_returned, _EMPTY_TRACE_ID)
+        self.assertEqual(trace_id, None)
+        self.assertEqual(trace_id_returned, None)
 
     def test_trace_id_valid_context_header(self):
         from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
         from google.cloud.logging.handlers._helpers import get_trace_id
 
-        FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
-        FLASK_TRACE_ID = 'testtraceidflask/testspanid'
+        flask_trace_header = 'X_CLOUD_TRACE_CONTEXT'
+        flask_trace_id = 'testtraceidflask/testspanid'
 
         with self.app.test_request_context(
                 path='/',
-                headers={FLASK_TRACE_HEADER:FLASK_TRACE_ID}):
+                headers={flask_trace_header:flask_trace_id}):
             trace_id = get_trace_id_from_flask()
             trace_id_returned = get_trace_id()
 
-        EXPECTED_TRACE_ID = 'testtraceidflask'
-        self.assertEqual(trace_id, EXPECTED_TRACE_ID)
+        expected_trace_id = 'testtraceidflask'
+        self.assertEqual(trace_id, expected_trace_id)
         self.assertEqual(trace_id, trace_id_returned)
 
 
@@ -73,48 +72,51 @@ def setUp(self):
             settings.configure()
         setup_test_environment()
 
+    def tearDown(self):
+        from django.test.utils import teardown_test_environment
+
+        teardown_test_environment()
+
     def test_trace_id_no_context_header(self):
-        import mock
         from django.test import RequestFactory
         from google.cloud.logging.handlers._helpers import get_trace_id_from_django
         from google.cloud.logging.handlers._helpers import get_trace_id
-        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
+        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+        from google.cloud.logging.handlers.middleware.request import _thread_locals
 
         request = RequestFactory().get('/')
 
-        with mock.patch(
-                'google.cloud.logging.handlers.middleware.RequestMiddleware.get_request',
-                return_value=request):
-            trace_id = get_trace_id_from_django()
-            trace_id_returned = get_trace_id()
+        middleware = RequestMiddleware()
+        middleware.process_request(request)
+        trace_id = get_trace_id_from_django()
+        trace_id_returned = get_trace_id()
 
-        self.assertEqual(trace_id, _EMPTY_TRACE_ID)
-        self.assertEqual(trace_id_returned, _EMPTY_TRACE_ID)
+        self.assertEqual(trace_id, None)
+        self.assertEqual(trace_id_returned, None)
+
+        _thread_locals.__dict__.clear()
 
     def test_trace_id_valid_context_header(self):
-        import mock
         from django.test import RequestFactory
         from google.cloud.logging.handlers._helpers import get_trace_id_from_django
         from google.cloud.logging.handlers._helpers import get_trace_id
+        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+        from google.cloud.logging.handlers.middleware.request import _thread_locals
 
-        DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
-        DJANGO_TRACE_ID = 'testtraceiddjango/testspanid'
+        django_trace_header = 'HTTP_X_CLOUD_TRACE_CONTEXT'
+        django_trace_id = 'testtraceiddjango/testspanid'
 
         request = RequestFactory().get(
             '/',
-            **{DJANGO_TRACE_HEADER:DJANGO_TRACE_ID})
+            **{django_trace_header:django_trace_id})
 
-        with mock.patch(
-                'google.cloud.logging.handlers.middleware.RequestMiddleware.get_request',
-                return_value=request):
-            trace_id = get_trace_id_from_django()
-            trace_id_returned = get_trace_id()
+        middleware = RequestMiddleware()
+        middleware.process_request(request)
+        trace_id = get_trace_id_from_django()
+        trace_id_returned = get_trace_id()
 
-        EXPECTED_TRACE_ID = 'testtraceiddjango'
-        self.assertEqual(trace_id, EXPECTED_TRACE_ID)
+        expected_trace_id = 'testtraceiddjango'
+        self.assertEqual(trace_id, expected_trace_id)
         self.assertEqual(trace_id, trace_id_returned)
 
-    def tearDown(self):
-        from django.test.utils import teardown_test_environment
-
-        teardown_test_environment()
+        _thread_locals.__dict__.clear()
diff --git a/logging/tests/unit/handlers/test_app_engine.py b/logging/tests/unit/handlers/test_app_engine.py
index 886dbbbb5584..ccdaf2992335 100644
--- a/logging/tests/unit/handlers/test_app_engine.py
+++ b/logging/tests/unit/handlers/test_app_engine.py
@@ -32,9 +32,7 @@ def test_constructor(self):
         from google.cloud.logging.handlers.app_engine import _GAE_PROJECT_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_SERVICE_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_VERSION_ENV
-        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
-
-        TRACE_ID_LABEL = 'appengine.googleapis.com/trace_id'
+        from google.cloud.logging.handlers.app_engine import _TRACE_ID_LABEL
 
         client = mock.Mock(project=self.PROJECT, spec=['project'])
 
@@ -47,7 +45,7 @@ def test_constructor(self):
         self.assertEqual(handler.resource.labels['project_id'], 'test_project')
         self.assertEqual(handler.resource.labels['module_id'], 'test_service')
         self.assertEqual(handler.resource.labels['version_id'], 'test_version')
-        self.assertEqual(handler.labels[TRACE_ID_LABEL], _EMPTY_TRACE_ID)
+        self.assertEqual(handler.labels, {})
 
     def test_emit(self):
         import mock

From 61237646c11f8fe66b0f2024552ea32118ad66a1 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Tue, 30 May 2017 12:28:30 -0700
Subject: [PATCH 28/47] Address jon's comments

---
 logging/google/cloud/logging/handlers/_helpers.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 2c88f427f00b..00135d0fe243 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -80,10 +80,12 @@ def get_trace_id_from_django():
         return None
 
     try:
-        header = request.META[_DJANGO_TRACE_HEADER]
+        header = request.META.get(_DJANGO_TRACE_HEADER)
     except KeyError:
         return None
 
+    if not header:
+        return None
     trace_id = header.split('/')[0]
 
     return trace_id
@@ -102,4 +104,4 @@ def get_trace_id():
         if trace_id is not None:
             return trace_id
 
-    return trace_id
+    return None

From 3caccc7cc0ae40b933d06ec354d796feee1af56f Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 2 Jun 2017 00:28:10 -0700
Subject: [PATCH 29/47] Address all comments

---
 .../google/cloud/logging/handlers/_helpers.py | 14 ++---
 .../logging/handlers/middleware/request.py    |  6 +-
 logging/nox.py                                |  4 +-
 .../unit/handlers/middleware/test_request.py  | 18 +++---
 logging/tests/unit/handlers/test__helpers.py  | 56 +++++++++----------
 logging/tests/unit/handlers/test_handlers.py  |  4 +-
 .../transports/test_background_thread.py      |  3 +-
 .../unit/handlers/transports/test_sync.py     |  3 +-
 8 files changed, 58 insertions(+), 50 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 00135d0fe243..e5bdabe2e388 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -22,7 +22,7 @@
 except ImportError:
     flask = None
 
-from google.cloud.logging.handlers.middleware.request import _get_request
+from google.cloud.logging.handlers.middleware.request import _get_django_request
 
 _FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
 _DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
@@ -55,12 +55,12 @@ def get_trace_id_from_flask():
     :rtype: str
     :return: Trace_id in HTTP request headers.
     """
-    if not flask or not flask.request:
+    if flask is None or not flask.request:
         return None
 
     header = flask.request.headers.get(_FLASK_TRACE_HEADER)
 
-    if not header:
+    if header is None:
         return None
 
     trace_id = header.split('/')[0]
@@ -74,9 +74,9 @@ def get_trace_id_from_django():
     :rtype: str
     :return: Trace_id in HTTP request headers.
     """
-    request = _get_request()
+    request = _get_django_request()
 
-    if not request:
+    if request is None:
         return None
 
     try:
@@ -84,7 +84,7 @@ def get_trace_id_from_django():
     except KeyError:
         return None
 
-    if not header:
+    if header is None:
         return None
     trace_id = header.split('/')[0]
 
@@ -97,7 +97,7 @@ def get_trace_id():
     :rtype: str
     :returns: Trace_id in HTTP request headers.
     """
-    checkers = [get_trace_id_from_django, get_trace_id_from_flask]
+    checkers = (get_trace_id_from_django, get_trace_id_from_flask)
 
     for checker in checkers:
         trace_id = checker()
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index 9baf11f4dbbe..1acf7ffd9961 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -12,13 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from threading import local
+import threading
 
 
-_thread_locals = local()
+_thread_locals = threading.local()
 
 
-def _get_request():
+def _get_django_request():
     """Get Django request from thread local.
 
     :rtype: str
diff --git a/logging/nox.py b/logging/nox.py
index de975600fd04..fbbbec1958c1 100644
--- a/logging/nox.py
+++ b/logging/nox.py
@@ -31,7 +31,9 @@ def unit_tests(session, python_version):
     session.interpreter = 'python{}'.format(python_version)
 
     # Install all test dependencies, then install this package in-place.
-    session.install('mock', 'pytest', 'pytest-cov', 'flask', 'django', *LOCAL_DEPS)
+    session.install(
+        'mock', 'pytest', 'pytest-cov',
+        'flask', 'django', *LOCAL_DEPS)
     session.install('-e', '.')
 
     # Run py.test against the unit tests.
diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
index 349247805104..ab8c18d1aa0e 100644
--- a/logging/tests/unit/handlers/middleware/test_request.py
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -25,7 +25,8 @@ def _get_target_class(self):
     def _make_one(self, *args, **kw):
         return self._get_target_class()(*args, **kw)
 
-    def setUp(self):
+    @classmethod
+    def setUpClass(cls):
         from django.conf import settings
         from django.test.utils import setup_test_environment
 
@@ -33,16 +34,17 @@ def setUp(self):
             settings.configure()
         setup_test_environment()
 
-    def tearDown(self):
+    @classmethod
+    def tearDownClass(cls):
         from django.test.utils import teardown_test_environment
 
         teardown_test_environment()
 
-    def test_get_request(self):
+    def test_get_django_request(self):
         from django.test import RequestFactory
-        from google.cloud.logging.handlers.middleware.request import _get_request
+        from google.cloud.logging.handlers.middleware.request import _get_django_request
 
-        self.middleware = self._make_one()
-        self.request = RequestFactory().get('/')
-        self.middleware.process_request(self.request)
-        self.assertEqual(_get_request(), self.request)
+        middleware = self._make_one()
+        request = RequestFactory().get('/')
+        middleware.process_request(request)
+        self.assertEqual(_get_django_request(), request)
diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
index 634ceb26e8a6..59e56f34524b 100644
--- a/logging/tests/unit/handlers/test__helpers.py
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -15,9 +15,10 @@
 import unittest
 
 
-class TestFlaskTrace(unittest.TestCase):
+class Test_get_trace_id_from_flask(unittest.TestCase):
 
-    def create_app(self):
+    @staticmethod
+    def create_app():
         import flask
 
         app = flask.Flask(__name__)
@@ -29,40 +30,41 @@ def index():
         return app
 
     def setUp(self):
-        self.app = self.create_app()
+        self.app = Test_get_trace_id_from_flask.create_app()
 
     def test_trace_id_no_context_header(self):
-        from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
-        from google.cloud.logging.handlers._helpers import get_trace_id
+        from google.cloud.logging.handlers import _helpers
 
         with self.app.test_request_context(
                 path='/',
                 headers={}):
-            trace_id = get_trace_id_from_flask()
-            trace_id_returned = get_trace_id()
+            trace_id = _helpers.get_trace_id_from_flask()
+            trace_id_returned = _helpers.get_trace_id()
 
-        self.assertEqual(trace_id, None)
-        self.assertEqual(trace_id_returned, None)
+        self.assertIsNone(trace_id)
+        self.assertIsNone(trace_id_returned)
 
     def test_trace_id_valid_context_header(self):
         from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
         from google.cloud.logging.handlers._helpers import get_trace_id
 
         flask_trace_header = 'X_CLOUD_TRACE_CONTEXT'
-        flask_trace_id = 'testtraceidflask/testspanid'
+        expected_trace_id = 'testtraceidflask'
+        flask_trace_id = expected_trace_id + '/testspanid'
 
-        with self.app.test_request_context(
-                path='/',
-                headers={flask_trace_header:flask_trace_id}):
+        context = self.app.test_request_context(
+            path='/',
+            headers={flask_trace_header: flask_trace_id})
+
+        with context:
             trace_id = get_trace_id_from_flask()
             trace_id_returned = get_trace_id()
 
-        expected_trace_id = 'testtraceidflask'
         self.assertEqual(trace_id, expected_trace_id)
         self.assertEqual(trace_id, trace_id_returned)
 
 
-class TestDjangoTrace(unittest.TestCase):
+class Test_get_trace_id_from_django(unittest.TestCase):
 
     def setUp(self):
         from django.conf import settings
@@ -79,22 +81,20 @@ def tearDown(self):
 
     def test_trace_id_no_context_header(self):
         from django.test import RequestFactory
-        from google.cloud.logging.handlers._helpers import get_trace_id_from_django
-        from google.cloud.logging.handlers._helpers import get_trace_id
-        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
-        from google.cloud.logging.handlers.middleware.request import _thread_locals
+        from google.cloud.logging.handlers import _helpers
+        from google.cloud.logging.handlers.middleware import request
 
-        request = RequestFactory().get('/')
+        django_request = RequestFactory().get('/')
 
-        middleware = RequestMiddleware()
-        middleware.process_request(request)
-        trace_id = get_trace_id_from_django()
-        trace_id_returned = get_trace_id()
+        middleware = request.RequestMiddleware()
+        middleware.process_request(django_request)
+        trace_id = _helpers.get_trace_id_from_django()
+        trace_id_returned = _helpers.get_trace_id()
 
-        self.assertEqual(trace_id, None)
-        self.assertEqual(trace_id_returned, None)
+        self.assertIsNone(trace_id)
+        self.assertIsNone(trace_id_returned)
 
-        _thread_locals.__dict__.clear()
+        request._thread_locals.__dict__.clear()
 
     def test_trace_id_valid_context_header(self):
         from django.test import RequestFactory
@@ -108,7 +108,7 @@ def test_trace_id_valid_context_header(self):
 
         request = RequestFactory().get(
             '/',
-            **{django_trace_header:django_trace_id})
+            **{django_trace_header: django_trace_id})
 
         middleware = RequestMiddleware()
         middleware.process_request(request)
diff --git a/logging/tests/unit/handlers/test_handlers.py b/logging/tests/unit/handlers/test_handlers.py
index 5459a0c10b96..96823b2e906d 100644
--- a/logging/tests/unit/handlers/test_handlers.py
+++ b/logging/tests/unit/handlers/test_handlers.py
@@ -45,7 +45,9 @@ def test_emit(self):
                                    None, None)
         handler.emit(record)
 
-        self.assertEqual(handler.transport.send_called_with, (record, message, _GLOBAL_RESOURCE, None))
+        self.assertEqual(
+            handler.transport.send_called_with,
+            (record, message, _GLOBAL_RESOURCE, None))
 
 
 class TestSetupLogging(unittest.TestCase):
diff --git a/logging/tests/unit/handlers/transports/test_background_thread.py b/logging/tests/unit/handlers/transports/test_background_thread.py
index b9449ce56685..f6671273b53d 100644
--- a/logging/tests/unit/handlers/transports/test_background_thread.py
+++ b/logging/tests/unit/handlers/transports/test_background_thread.py
@@ -63,7 +63,8 @@ def test_send(self):
 
         transport.send(record, message, _GLOBAL_RESOURCE, None)
 
-        transport.worker.enqueue.assert_called_once_with(record, message, _GLOBAL_RESOURCE, None)
+        transport.worker.enqueue.assert_called_once_with(
+            record, message, _GLOBAL_RESOURCE, None)
 
     def test_flush(self):
         client = _Client(self.PROJECT)
diff --git a/logging/tests/unit/handlers/transports/test_sync.py b/logging/tests/unit/handlers/transports/test_sync.py
index e18920ce2167..01c15240f3b7 100644
--- a/logging/tests/unit/handlers/transports/test_sync.py
+++ b/logging/tests/unit/handlers/transports/test_sync.py
@@ -63,7 +63,8 @@ class _Logger(object):
     def __init__(self, name):
         self.name = name
 
-    def log_struct(self, message, severity=None, resource=_GLOBAL_RESOURCE, labels=None):
+    def log_struct(self, message, severity=None,
+                   resource=_GLOBAL_RESOURCE, labels=None):
         self.log_struct_called_with = (message, severity, resource, labels)
 
 

From 4589a06e322402c18587304d41069769f5fbfbcb Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 2 Jun 2017 00:34:48 -0700
Subject: [PATCH 30/47] fix style

---
 logging/tests/unit/handlers/test__helpers.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
index 59e56f34524b..c50ce0044e85 100644
--- a/logging/tests/unit/handlers/test__helpers.py
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -104,7 +104,8 @@ def test_trace_id_valid_context_header(self):
         from google.cloud.logging.handlers.middleware.request import _thread_locals
 
         django_trace_header = 'HTTP_X_CLOUD_TRACE_CONTEXT'
-        django_trace_id = 'testtraceiddjango/testspanid'
+        expected_trace_id = 'testtraceiddjango'
+        django_trace_id = expected_trace_id + '/testspanid'
 
         request = RequestFactory().get(
             '/',
@@ -115,7 +116,6 @@ def test_trace_id_valid_context_header(self):
         trace_id = get_trace_id_from_django()
         trace_id_returned = get_trace_id()
 
-        expected_trace_id = 'testtraceiddjango'
         self.assertEqual(trace_id, expected_trace_id)
         self.assertEqual(trace_id, trace_id_returned)
 

From 2889cfc8fc23ce2bde735339d77887136836898b Mon Sep 17 00:00:00 2001
From: Danny Hermes <daniel.j.hermes@gmail.com>
Date: Fri, 2 Jun 2017 11:43:59 -0700
Subject: [PATCH 31/47] Tweaks for style / coverage / lint.

---
 .../google/cloud/logging/handlers/_helpers.py |  12 +-
 .../cloud/logging/handlers/app_engine.py      |   5 +-
 .../logging/handlers/middleware/request.py    |   6 +
 .../unit/handlers/middleware/test_request.py  |  62 ++++++++--
 logging/tests/unit/handlers/test__helpers.py  | 115 +++++++++++++-----
 .../tests/unit/handlers/test_app_engine.py    |  36 +++++-
 6 files changed, 179 insertions(+), 57 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index e5bdabe2e388..8eb2434a27a0 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -19,10 +19,11 @@
 
 try:
     import flask
-except ImportError:
+except ImportError:  # pragma: NO COVER
     flask = None
 
-from google.cloud.logging.handlers.middleware.request import _get_django_request
+from google.cloud.logging.handlers.middleware.request import (
+    _get_django_request)
 
 _FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
 _DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
@@ -79,13 +80,10 @@ def get_trace_id_from_django():
     if request is None:
         return None
 
-    try:
-        header = request.META.get(_DJANGO_TRACE_HEADER)
-    except KeyError:
-        return None
-
+    header = request.META.get(_DJANGO_TRACE_HEADER)
     if header is None:
         return None
+
     trace_id = header.split('/')[0]
 
     return trace_id
diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index f8b12c44a42e..f1998a9ee13e 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -73,7 +73,10 @@ def get_gae_resource(self):
         return gae_resource
 
     def get_gae_labels(self):
-        """Return the labels for GAE app which includes trace_id.
+        """Return the labels for GAE app.
+
+        If the trace ID can be detected, it will be included as a label.
+        Currently, no other labels are included.
 
         :rtype: dict
         :returns: Labels for GAE app.
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index 1acf7ffd9961..4c0b22a8e96b 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -12,6 +12,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+"""Django middleware helper to capture a request.
+
+The request is stored on a thread-local so that it can be
+inspected by other helpers.
+"""
+
 import threading
 
 
diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
index ab8c18d1aa0e..983d67129647 100644
--- a/logging/tests/unit/handlers/middleware/test_request.py
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -14,16 +14,10 @@
 
 import unittest
 
+import mock
 
-class TestRequestMiddleware(unittest.TestCase):
 
-    def _get_target_class(self):
-        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
-
-        return RequestMiddleware
-
-    def _make_one(self, *args, **kw):
-        return self._get_target_class()(*args, **kw)
+class DjangoBase(unittest.TestCase):
 
     @classmethod
     def setUpClass(cls):
@@ -40,11 +34,53 @@ def tearDownClass(cls):
 
         teardown_test_environment()
 
-    def test_get_django_request(self):
+
+class TestRequestMiddleware(DjangoBase):
+
+    def _get_target_class(self):
+        from google.cloud.logging.handlers.middleware import request
+
+        return request.RequestMiddleware
+
+    def _make_one(self, *args, **kw):
+        return self._get_target_class()(*args, **kw)
+
+    def test_process_request(self):
         from django.test import RequestFactory
-        from google.cloud.logging.handlers.middleware.request import _get_django_request
+        from google.cloud.logging.handlers.middleware import request
 
         middleware = self._make_one()
-        request = RequestFactory().get('/')
-        middleware.process_request(request)
-        self.assertEqual(_get_django_request(), request)
+        mock_request = RequestFactory().get('/')
+        middleware.process_request(mock_request)
+
+        django_request = request._get_django_request()
+        self.assertEqual(django_request, mock_request)
+
+
+class Test__get_django_request(DjangoBase):
+
+    @staticmethod
+    def _call_fut():
+        from google.cloud.logging.handlers.middleware import request
+
+        return request._get_django_request()
+
+    @staticmethod
+    def _make_patch(new_locals):
+        return mock.patch(
+            'google.cloud.logging.handlers.middleware.request._thread_locals',
+            new=new_locals)
+
+    def test_with_request(self):
+        thread_locals = mock.Mock(spec=['request'])
+        with self._make_patch(thread_locals):
+            django_request = self._call_fut()
+
+        self.assertIs(django_request, thread_locals.request)
+
+    def test_without_request(self):
+        thread_locals = mock.Mock(spec=[])
+        with self._make_patch(thread_locals):
+            django_request = self._call_fut()
+
+        self.assertIsNone(django_request)
diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
index c50ce0044e85..a69e765afa98 100644
--- a/logging/tests/unit/handlers/test__helpers.py
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -14,9 +14,17 @@
 
 import unittest
 
+import mock
+
 
 class Test_get_trace_id_from_flask(unittest.TestCase):
 
+    @staticmethod
+    def _call_fut():
+        from google.cloud.logging.handlers import _helpers
+
+        return _helpers.get_trace_id_from_flask()
+
     @staticmethod
     def create_app():
         import flask
@@ -30,24 +38,19 @@ def index():
         return app
 
     def setUp(self):
-        self.app = Test_get_trace_id_from_flask.create_app()
+        self.app = self.create_app()
 
-    def test_trace_id_no_context_header(self):
+    def test_no_context_header(self):
         from google.cloud.logging.handlers import _helpers
 
         with self.app.test_request_context(
                 path='/',
                 headers={}):
-            trace_id = _helpers.get_trace_id_from_flask()
-            trace_id_returned = _helpers.get_trace_id()
+            trace_id = self._call_fut()
 
         self.assertIsNone(trace_id)
-        self.assertIsNone(trace_id_returned)
-
-    def test_trace_id_valid_context_header(self):
-        from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
-        from google.cloud.logging.handlers._helpers import get_trace_id
 
+    def test_valid_context_header(self):
         flask_trace_header = 'X_CLOUD_TRACE_CONTEXT'
         expected_trace_id = 'testtraceidflask'
         flask_trace_id = expected_trace_id + '/testspanid'
@@ -57,15 +60,19 @@ def test_trace_id_valid_context_header(self):
             headers={flask_trace_header: flask_trace_id})
 
         with context:
-            trace_id = get_trace_id_from_flask()
-            trace_id_returned = get_trace_id()
+            trace_id = self._call_fut()
 
         self.assertEqual(trace_id, expected_trace_id)
-        self.assertEqual(trace_id, trace_id_returned)
 
 
 class Test_get_trace_id_from_django(unittest.TestCase):
 
+    @staticmethod
+    def _call_fut():
+        from google.cloud.logging.handlers import _helpers
+
+        return _helpers.get_trace_id_from_django()
+
     def setUp(self):
         from django.conf import settings
         from django.test.utils import setup_test_environment
@@ -76,47 +83,91 @@ def setUp(self):
 
     def tearDown(self):
         from django.test.utils import teardown_test_environment
+        from google.cloud.logging.handlers.middleware import request
 
         teardown_test_environment()
+        request._thread_locals.__dict__.clear()
 
-    def test_trace_id_no_context_header(self):
+    def test_no_context_header(self):
         from django.test import RequestFactory
-        from google.cloud.logging.handlers import _helpers
         from google.cloud.logging.handlers.middleware import request
 
         django_request = RequestFactory().get('/')
 
         middleware = request.RequestMiddleware()
         middleware.process_request(django_request)
-        trace_id = _helpers.get_trace_id_from_django()
-        trace_id_returned = _helpers.get_trace_id()
-
+        trace_id = self._call_fut()
         self.assertIsNone(trace_id)
-        self.assertIsNone(trace_id_returned)
 
-        request._thread_locals.__dict__.clear()
-
-    def test_trace_id_valid_context_header(self):
+    def test_valid_context_header(self):
         from django.test import RequestFactory
-        from google.cloud.logging.handlers._helpers import get_trace_id_from_django
-        from google.cloud.logging.handlers._helpers import get_trace_id
-        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
-        from google.cloud.logging.handlers.middleware.request import _thread_locals
+        from google.cloud.logging.handlers.middleware import request
 
         django_trace_header = 'HTTP_X_CLOUD_TRACE_CONTEXT'
         expected_trace_id = 'testtraceiddjango'
         django_trace_id = expected_trace_id + '/testspanid'
 
-        request = RequestFactory().get(
+        django_request = RequestFactory().get(
             '/',
             **{django_trace_header: django_trace_id})
 
-        middleware = RequestMiddleware()
-        middleware.process_request(request)
-        trace_id = get_trace_id_from_django()
-        trace_id_returned = get_trace_id()
+        middleware = request.RequestMiddleware()
+        middleware.process_request(django_request)
+        trace_id = self._call_fut()
 
         self.assertEqual(trace_id, expected_trace_id)
-        self.assertEqual(trace_id, trace_id_returned)
 
-        _thread_locals.__dict__.clear()
+
+class Test_get_trace_id(unittest.TestCase):
+
+    @staticmethod
+    def _call_fut():
+        from google.cloud.logging.handlers import _helpers
+
+        return _helpers.get_trace_id()
+
+    def _helper(self, django_return, flask_return):
+        django_patch = mock.patch(
+            'google.cloud.logging.handlers._helpers.get_trace_id_from_django',
+            return_value=django_return)
+        flask_patch = mock.patch(
+            'google.cloud.logging.handlers._helpers.get_trace_id_from_flask',
+            return_value=flask_return)
+
+        with django_patch as django_mock:
+            with flask_patch as flask_mock:
+                trace_id = self._call_fut()
+
+        return django_mock, flask_mock, trace_id
+
+    def test_from_django(self):
+        django_mock, flask_mock, trace_id = self._helper(
+            'test-django-trace-id', None)
+        self.assertEqual(trace_id, django_mock.return_value)
+
+        django_mock.assert_called_once_with()
+        flask_mock.assert_not_called()
+
+    def test_from_flask(self):
+        django_mock, flask_mock, trace_id = self._helper(
+            None, 'test-flask-trace-id')
+        self.assertEqual(trace_id, flask_mock.return_value)
+
+        django_mock.assert_called_once_with()
+        flask_mock.assert_called_once_with()
+
+    def test_from_django_and_flask(self):
+        django_mock, flask_mock, trace_id = self._helper(
+            'test-django-trace-id', 'test-flask-trace-id')
+        # Django wins.
+        self.assertEqual(trace_id, django_mock.return_value)
+
+        django_mock.assert_called_once_with()
+        flask_mock.assert_not_called()
+
+    def test_missing(self):
+        django_mock, flask_mock, trace_id = self._helper(None, None)
+        self.assertIsNone(trace_id)
+
+        django_mock.assert_called_once_with()
+        flask_mock.assert_called_once_with()
diff --git a/logging/tests/unit/handlers/test_app_engine.py b/logging/tests/unit/handlers/test_app_engine.py
index ccdaf2992335..6438c4abb8a0 100644
--- a/logging/tests/unit/handlers/test_app_engine.py
+++ b/logging/tests/unit/handlers/test_app_engine.py
@@ -15,8 +15,10 @@
 import logging
 import unittest
 
+import mock
 
-class TestAppEngineHandlerHandler(unittest.TestCase):
+
+class TestAppEngineHandler(unittest.TestCase):
     PROJECT = 'PROJECT'
 
     def _get_target_class(self):
@@ -28,7 +30,6 @@ def _make_one(self, *args, **kw):
         return self._get_target_class()(*args, **kw)
 
     def test_constructor(self):
-        import mock
         from google.cloud.logging.handlers.app_engine import _GAE_PROJECT_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_SERVICE_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_VERSION_ENV
@@ -48,8 +49,6 @@ def test_constructor(self):
         self.assertEqual(handler.labels, {})
 
     def test_emit(self):
-        import mock
-
         client = mock.Mock(project=self.PROJECT, spec=['project'])
         handler = self._make_one(client, transport=_Transport)
         gae_resource = handler.get_gae_resource()
@@ -66,6 +65,35 @@ def test_emit(self):
             handler.transport.send_called_with,
             (record, message, gae_resource, gae_labels))
 
+    def _get_gae_labels_helper(self, trace_id):
+        get_trace_patch = mock.patch(
+            'google.cloud.logging.handlers.app_engine.get_trace_id',
+            return_value=trace_id)
+
+        client = mock.Mock(project=self.PROJECT, spec=['project'])
+        # The handler actually calls ``get_gae_labels()``.
+        with get_trace_patch as mock_get_trace:
+            handler = self._make_one(client, transport=_Transport)
+            mock_get_trace.assert_called_once_with()
+
+            gae_labels = handler.get_gae_labels()
+            self.assertEqual(mock_get_trace.mock_calls,
+                             [mock.call(), mock.call()])
+
+        return gae_labels
+
+    def test_get_gae_labels_with_label(self):
+        from google.cloud.logging.handlers import app_engine
+
+        trace_id = 'test-gae-trace-id'
+        gae_labels = self._get_gae_labels_helper(trace_id)
+        expected_labels = {app_engine._TRACE_ID_LABEL: trace_id}
+        self.assertEqual(gae_labels, expected_labels)
+
+    def test_get_gae_labels_without_label(self):
+        gae_labels = self._get_gae_labels_helper(None)
+        self.assertEqual(gae_labels, {})
+
 
 class _Transport(object):
 

From 195707739b43c11a259a8eb6f2aa32da3aba9857 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Mon, 22 May 2017 16:44:45 -0700
Subject: [PATCH 32/47] Send trace context with logs from web applications

---
 .../google/cloud/logging/handlers/_helpers.py | 39 ++++++++++++++++++
 .../cloud/logging/handlers/app_engine.py      | 18 ++++++++-
 .../google/cloud/logging/handlers/handlers.py | 12 +++++-
 .../logging/handlers/middleware/__init__.py   | 17 ++++++++
 .../logging/handlers/middleware/request.py    | 40 +++++++++++++++++++
 .../handlers/transports/background_thread.py  | 13 ++++--
 .../cloud/logging/handlers/transports/base.py |  5 ++-
 .../cloud/logging/handlers/transports/sync.py | 11 ++++-
 8 files changed, 146 insertions(+), 9 deletions(-)
 create mode 100644 logging/google/cloud/logging/handlers/middleware/__init__.py
 create mode 100644 logging/google/cloud/logging/handlers/middleware/request.py

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 81adcf0eb545..97b44d53ec19 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -17,6 +17,23 @@
 import math
 import json
 
+try:
+    import django
+except ImportError:
+    _USE_DJANGO = False
+else:
+    _USE_DJANGO = True
+
+try:
+    import flask
+except ImportError:
+    _USE_FLASK = False
+    flask = None
+else:
+    _USE_FLASK = True
+
+from google.cloud.logging.handlers.middleware.request import get_request
+
 
 def format_stackdriver_json(record, message):
     """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -37,3 +54,25 @@ def format_stackdriver_json(record, message):
     }
 
     return json.dumps(payload)
+
+
+def get_trace_id_from_request_header():
+    """Helper to get trace_id from web application request header.
+
+    :rtype: str
+    :returns: Trace_id in HTTP request headers.
+    """
+    if _USE_FLASK:
+        try:
+            trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]
+        except Exception:
+            trace_id = None
+    elif _USE_DJANGO:
+        try:
+            request = get_request()
+            trace_id = request.META['HTTP_X_CLOUD_TRACE_CONTEXT'].split('/')[0]
+        except Exception:
+            trace_id = None
+    else:
+        trace_id = None
+    return trace_id
diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index 7011819f8a2f..04e35d3c547e 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -20,6 +20,7 @@
 
 import os
 
+from google.cloud.logging.handlers._helpers import get_trace_id_from_request_header
 from google.cloud.logging.handlers.handlers import CloudLoggingHandler
 from google.cloud.logging.handlers.transports import BackgroundThreadTransport
 from google.cloud.logging.resource import Resource
@@ -50,7 +51,8 @@ def __init__(self, client,
             client,
             name=_DEFAULT_GAE_LOGGER_NAME,
             transport=transport,
-            resource=self.get_gae_resource())
+            resource=self.get_gae_resource(),
+            labels=self.get_gae_labels())
 
     def get_gae_resource(self):
         """Return the GAE resource using the environment variables.
@@ -67,3 +69,17 @@ def get_gae_resource(self):
             },
         )
         return gae_resource
+
+    def get_gae_labels(self):
+        """Return the labels for GAE app which includes trace_id.
+
+        :rtype: dict
+        :returns: Labels for GAE app.
+        """
+        trace_id = get_trace_id_from_request_header()
+        if trace_id is None:
+            trace_id = 'unknown'
+        gae_labels = {
+            'appengine.googleapis.com/trace_id': trace_id,
+        }
+        return gae_labels
\ No newline at end of file
diff --git a/logging/google/cloud/logging/handlers/handlers.py b/logging/google/cloud/logging/handlers/handlers.py
index 97afde9f87fb..7f094bba19b1 100644
--- a/logging/google/cloud/logging/handlers/handlers.py
+++ b/logging/google/cloud/logging/handlers/handlers.py
@@ -57,6 +57,9 @@ class CloudLoggingHandler(logging.StreamHandler):
     :param resource: (Optional) Monitored resource of the entry, defaults
                      to the global resource type.
 
+    :type labels: dict
+    :param labels: (Optional) Mapping of labels for the entry.
+
     Example:
 
     .. code-block:: python
@@ -79,12 +82,14 @@ class CloudLoggingHandler(logging.StreamHandler):
     def __init__(self, client,
                  name=DEFAULT_LOGGER_NAME,
                  transport=BackgroundThreadTransport,
-                 resource=_GLOBAL_RESOURCE):
+                 resource=_GLOBAL_RESOURCE,
+                 labels=None):
         super(CloudLoggingHandler, self).__init__()
         self.name = name
         self.client = client
         self.transport = transport(client, name)
         self.resource = resource
+        self.labels = labels
 
     def emit(self, record):
         """Actually log the specified logging record.
@@ -97,7 +102,10 @@ def emit(self, record):
         :param record: The record to be logged.
         """
         message = super(CloudLoggingHandler, self).format(record)
-        self.transport.send(record, message, resource=self.resource)
+        self.transport.send(record,
+                            message,
+                            resource=self.resource,
+                            labels=self.labels)
 
 
 def setup_logging(handler, excluded_loggers=EXCLUDED_LOGGER_DEFAULTS,
diff --git a/logging/google/cloud/logging/handlers/middleware/__init__.py b/logging/google/cloud/logging/handlers/middleware/__init__.py
new file mode 100644
index 000000000000..79c3abee7894
--- /dev/null
+++ b/logging/google/cloud/logging/handlers/middleware/__init__.py
@@ -0,0 +1,17 @@
+# Copyright 2016 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+
+__all__ = ['RequestMiddleware']
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
new file mode 100644
index 000000000000..0c6d1f46c5cd
--- /dev/null
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -0,0 +1,40 @@
+# Copyright 2016 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+try:
+    from threading import local
+except ImportError:
+    from django.utils._threading_local import local
+
+_thread_locals = local()
+
+
+def get_request():
+    """Get Django request from thread local.
+
+    :rtype: str
+    :returns: Django request.
+    """
+    return getattr(_thread_locals, 'request', None)
+
+class RequestMiddleware(object):
+    """Saves the request in thread local"""
+
+    def process_request(self, request):
+        """Called on each request, before Django decides which view to execute.
+
+        :type request: :class:`~django.http.request.HttpRequest`
+        :param request: Django http request.
+        """
+        _thread_locals.request = request
diff --git a/logging/google/cloud/logging/handlers/transports/background_thread.py b/logging/google/cloud/logging/handlers/transports/background_thread.py
index 010c06b36bc9..d889bed62626 100644
--- a/logging/google/cloud/logging/handlers/transports/background_thread.py
+++ b/logging/google/cloud/logging/handlers/transports/background_thread.py
@@ -203,7 +203,7 @@ def _main_thread_terminated(self):
         else:
             print('Failed to send %d pending logs.' % (self._queue.qsize(),))
 
-    def enqueue(self, record, message, resource=None):
+    def enqueue(self, record, message, resource=None, labels=None):
         """Queues a log entry to be written by the background thread.
 
         :type record: :class:`logging.LogRecord`
@@ -215,6 +215,9 @@ def enqueue(self, record, message, resource=None):
 
         :type resource: :class:`~google.cloud.logging.resource.Resource`
         :param resource: (Optional) Monitored resource of the entry
+
+        :type labels: dict
+        :param labels: (Optional) Mapping of labels for the entry.
         """
         self._queue.put_nowait({
             'info': {
@@ -223,6 +226,7 @@ def enqueue(self, record, message, resource=None):
             },
             'severity': record.levelname,
             'resource': resource,
+            'labels': labels,
         })
 
     def flush(self):
@@ -257,7 +261,7 @@ def __init__(self, client, name, grace_period=_DEFAULT_GRACE_PERIOD,
         self.worker = _Worker(logger)
         self.worker.start()
 
-    def send(self, record, message, resource=None):
+    def send(self, record, message, resource=None, labels=None):
         """Overrides Transport.send().
 
         :type record: :class:`logging.LogRecord`
@@ -269,8 +273,11 @@ def send(self, record, message, resource=None):
 
         :type resource: :class:`~google.cloud.logging.resource.Resource`
         :param resource: (Optional) Monitored resource of the entry.
+
+        :type labels: dict
+        :param labels: (Optional) Mapping of labels for the entry.
         """
-        self.worker.enqueue(record, message, resource=resource)
+        self.worker.enqueue(record, message, resource=resource, labels=labels)
 
     def flush(self):
         """Submit any pending log records."""
diff --git a/logging/google/cloud/logging/handlers/transports/base.py b/logging/google/cloud/logging/handlers/transports/base.py
index 21957021793f..7829201b1c98 100644
--- a/logging/google/cloud/logging/handlers/transports/base.py
+++ b/logging/google/cloud/logging/handlers/transports/base.py
@@ -22,7 +22,7 @@ class Transport(object):
     client and name object, and must override :meth:`send`.
     """
 
-    def send(self, record, message, resource=None):
+    def send(self, record, message, resource=None, labels=None):
         """Transport send to be implemented by subclasses.
 
         :type record: :class:`logging.LogRecord`
@@ -34,6 +34,9 @@ def send(self, record, message, resource=None):
 
         :type resource: :class:`~google.cloud.logging.resource.Resource`
         :param resource: (Optional) Monitored resource of the entry.
+
+        :type labels: dict
+        :param labels: (Optional) Mapping of labels for the entry.
         """
         raise NotImplementedError
 
diff --git a/logging/google/cloud/logging/handlers/transports/sync.py b/logging/google/cloud/logging/handlers/transports/sync.py
index 0dd6e0bd7e24..be70e60a14e1 100644
--- a/logging/google/cloud/logging/handlers/transports/sync.py
+++ b/logging/google/cloud/logging/handlers/transports/sync.py
@@ -29,7 +29,7 @@ class SyncTransport(Transport):
     def __init__(self, client, name):
         self.logger = client.logger(name)
 
-    def send(self, record, message, resource=None):
+    def send(self, record, message, resource=None, labels=None):
         """Overrides transport.send().
 
         :type record: :class:`logging.LogRecord`
@@ -38,8 +38,15 @@ def send(self, record, message, resource=None):
         :type message: str
         :param message: The message from the ``LogRecord`` after being
                         formatted by the associated log formatters.
+
+        :type resource: :class:`~google.cloud.logging.resource.Resource`
+        :param resource: (Optional) Monitored resource of the entry.
+
+        :type labels: dict
+        :param labels: (Optional) Mapping of labels for the entry.
         """
         info = {'message': message, 'python_logger': record.name}
         self.logger.log_struct(info,
                                severity=record.levelname,
-                               resource=resource)
+                               resource=resource,
+                               labels=labels)

From bf683f7e14b9d25b48a727f416cd63669c12480f Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Mon, 22 May 2017 16:58:43 -0700
Subject: [PATCH 33/47] Fix style

---
 logging/google/cloud/logging/handlers/app_engine.py         | 2 +-
 logging/google/cloud/logging/handlers/middleware/request.py | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index 04e35d3c547e..4d5972edfa51 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -82,4 +82,4 @@ def get_gae_labels(self):
         gae_labels = {
             'appengine.googleapis.com/trace_id': trace_id,
         }
-        return gae_labels
\ No newline at end of file
+        return gae_labels
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index 0c6d1f46c5cd..a37a6af47035 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -28,6 +28,7 @@ def get_request():
     """
     return getattr(_thread_locals, 'request', None)
 
+
 class RequestMiddleware(object):
     """Saves the request in thread local"""
 

From 51cdb39597937c29c4de505b3b4904396d7d3ea5 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Tue, 23 May 2017 14:23:32 -0700
Subject: [PATCH 34/47] Improved code for web framework detection

---
 .../google/cloud/logging/handlers/_helpers.py | 37 ++++++++++++++-----
 1 file changed, 27 insertions(+), 10 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 97b44d53ec19..a1c697ba404c 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -16,24 +16,18 @@
 
 import math
 import json
-
-try:
-    import django
-except ImportError:
-    _USE_DJANGO = False
-else:
-    _USE_DJANGO = True
+import sys
 
 try:
     import flask
 except ImportError:
-    _USE_FLASK = False
     flask = None
-else:
-    _USE_FLASK = True
 
 from google.cloud.logging.handlers.middleware.request import get_request
 
+_USE_FLASK = False
+_USE_DJANGO = False
+
 
 def format_stackdriver_json(record, message):
     """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -56,12 +50,35 @@ def format_stackdriver_json(record, message):
     return json.dumps(payload)
 
 
+def detect_web_framework():
+    """Detect web framework used in this environment.
+
+    Detect which web framework is used by looking at the sys.modules.
+    If multiple or no supported web frameworks detected in the modules, then
+    print a warning message.
+    Set _USE_FLASK or _USE_DJANGO to True if one of them are detected.
+    """
+    modules = sys.modules
+    global _USE_FLASK, _USE_DJANGO
+
+    if 'flask' in modules and 'django' in modules:
+        print('Cannot determine, found multiple web frameworks.')
+    elif 'flask' in modules:
+        _USE_FLASK = True
+    elif 'django' in modules:
+        _USE_DJANGO = True
+    else:
+        print('No supported web framework found in the modules.')
+
+
 def get_trace_id_from_request_header():
     """Helper to get trace_id from web application request header.
 
     :rtype: str
     :returns: Trace_id in HTTP request headers.
     """
+    detect_web_framework()
+
     if _USE_FLASK:
         try:
             trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]

From 2479d916625eebd27dc4627ade02115fa6534723 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Tue, 23 May 2017 14:28:01 -0700
Subject: [PATCH 35/47] Fix year

---
 logging/google/cloud/logging/handlers/middleware/__init__.py | 2 +-
 logging/google/cloud/logging/handlers/middleware/request.py  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/middleware/__init__.py b/logging/google/cloud/logging/handlers/middleware/__init__.py
index 79c3abee7894..c340235b8bdd 100644
--- a/logging/google/cloud/logging/handlers/middleware/__init__.py
+++ b/logging/google/cloud/logging/handlers/middleware/__init__.py
@@ -1,4 +1,4 @@
-# Copyright 2016 Google Inc. All Rights Reserved.
+# Copyright 2017 Google Inc. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index a37a6af47035..be5102487cc6 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -1,4 +1,4 @@
-# Copyright 2016 Google Inc. All Rights Reserved.
+# Copyright 2017 Google Inc. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.

From 6c04196b1e738e3bbe399f3fd6558b6f552e3930 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Tue, 23 May 2017 14:45:28 -0700
Subject: [PATCH 36/47] Drop module level variables

---
 .../google/cloud/logging/handlers/_helpers.py | 22 ++++++++++---------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index a1c697ba404c..6bf0edf79d54 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -25,9 +25,6 @@
 
 from google.cloud.logging.handlers.middleware.request import get_request
 
-_USE_FLASK = False
-_USE_DJANGO = False
-
 
 def format_stackdriver_json(record, message):
     """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -56,19 +53,24 @@ def detect_web_framework():
     Detect which web framework is used by looking at the sys.modules.
     If multiple or no supported web frameworks detected in the modules, then
     print a warning message.
-    Set _USE_FLASK or _USE_DJANGO to True if one of them are detected.
+    Return the name of web framework detected if flask or django is found.
+    Return unknown if cannot determine.
+
+    :rtype: str
+    :returns: Web framework detected in this environment.
     """
     modules = sys.modules
-    global _USE_FLASK, _USE_DJANGO
+    web_framework = 'unknown'
 
     if 'flask' in modules and 'django' in modules:
         print('Cannot determine, found multiple web frameworks.')
     elif 'flask' in modules:
-        _USE_FLASK = True
+        web_framework = 'flask'
     elif 'django' in modules:
-        _USE_DJANGO = True
+        web_framework = 'django'
     else:
         print('No supported web framework found in the modules.')
+    return web_framework
 
 
 def get_trace_id_from_request_header():
@@ -77,14 +79,14 @@ def get_trace_id_from_request_header():
     :rtype: str
     :returns: Trace_id in HTTP request headers.
     """
-    detect_web_framework()
+    web_framework = detect_web_framework()
 
-    if _USE_FLASK:
+    if web_framework is 'flask':
         try:
             trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]
         except Exception:
             trace_id = None
-    elif _USE_DJANGO:
+    elif web_framework is 'django':
         try:
             request = get_request()
             trace_id = request.META['HTTP_X_CLOUD_TRACE_CONTEXT'].split('/')[0]

From f70c84eba51d3a7b5d9bb407edd9b3b1017913aa Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Thu, 25 May 2017 10:07:25 -0700
Subject: [PATCH 37/47] Address Jon's comments and add some unit tests (not
 complete yet)

---
 .../google/cloud/logging/handlers/_helpers.py | 66 ++++++++-----------
 .../cloud/logging/handlers/app_engine.py      |  4 +-
 .../google/cloud/logging/handlers/handlers.py |  9 +--
 .../logging/handlers/middleware/request.py    |  6 +-
 .../tests/unit/handlers/test_app_engine.py    | 11 +++-
 logging/tests/unit/handlers/test_handlers.py  |  6 +-
 .../transports/test_background_thread.py      |  8 +--
 .../unit/handlers/transports/test_sync.py     |  6 +-
 8 files changed, 56 insertions(+), 60 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 6bf0edf79d54..0af7a53de476 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -16,7 +16,6 @@
 
 import math
 import json
-import sys
 
 try:
     import flask
@@ -47,51 +46,44 @@ def format_stackdriver_json(record, message):
     return json.dumps(payload)
 
 
-def detect_web_framework():
-    """Detect web framework used in this environment.
-
-    Detect which web framework is used by looking at the sys.modules.
-    If multiple or no supported web frameworks detected in the modules, then
-    print a warning message.
-    Return the name of web framework detected if flask or django is found.
-    Return unknown if cannot determine.
+def get_trace_id_from_flask():
+    """Get trace_id from flask request headers.
 
     :rtype: str
-    :returns: Web framework detected in this environment.
+    :return: Trace_id in HTTP request headers.
     """
-    modules = sys.modules
-    web_framework = 'unknown'
+    try:
+        trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]
+    except Exception:
+        trace_id = None
+    return trace_id
 
-    if 'flask' in modules and 'django' in modules:
-        print('Cannot determine, found multiple web frameworks.')
-    elif 'flask' in modules:
-        web_framework = 'flask'
-    elif 'django' in modules:
-        web_framework = 'django'
-    else:
-        print('No supported web framework found in the modules.')
-    return web_framework
+
+def get_trace_id_from_django():
+    """Get trace_id from django request headers.
+
+    :rtype: str
+    :return: Trace_id in HTTP request headers.
+    """
+    try:
+        request = get_request()
+        trace_id = request.META['HTTP_X_CLOUD_TRACE_CONTEXT'].split('/')[0]
+    except Exception:
+        trace_id = None
+    return trace_id
 
 
-def get_trace_id_from_request_header():
+def get_trace_id():
     """Helper to get trace_id from web application request header.
 
     :rtype: str
     :returns: Trace_id in HTTP request headers.
     """
-    web_framework = detect_web_framework()
-
-    if web_framework is 'flask':
-        try:
-            trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]
-        except Exception:
-            trace_id = None
-    elif web_framework is 'django':
-        try:
-            request = get_request()
-            trace_id = request.META['HTTP_X_CLOUD_TRACE_CONTEXT'].split('/')[0]
-        except Exception:
-            trace_id = None
-    else:
-        trace_id = None
+    checkers = [get_trace_id_from_django, get_trace_id_from_flask]
+
+    for checker in checkers:
+        trace_id = checker()
+        if trace_id is not None:
+            return trace_id
+
     return trace_id
diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index 4d5972edfa51..8ebb460f23c6 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -20,7 +20,7 @@
 
 import os
 
-from google.cloud.logging.handlers._helpers import get_trace_id_from_request_header
+from google.cloud.logging.handlers._helpers import get_trace_id
 from google.cloud.logging.handlers.handlers import CloudLoggingHandler
 from google.cloud.logging.handlers.transports import BackgroundThreadTransport
 from google.cloud.logging.resource import Resource
@@ -76,7 +76,7 @@ def get_gae_labels(self):
         :rtype: dict
         :returns: Labels for GAE app.
         """
-        trace_id = get_trace_id_from_request_header()
+        trace_id = get_trace_id()
         if trace_id is None:
             trace_id = 'unknown'
         gae_labels = {
diff --git a/logging/google/cloud/logging/handlers/handlers.py b/logging/google/cloud/logging/handlers/handlers.py
index 7f094bba19b1..fe9848848d38 100644
--- a/logging/google/cloud/logging/handlers/handlers.py
+++ b/logging/google/cloud/logging/handlers/handlers.py
@@ -102,10 +102,11 @@ def emit(self, record):
         :param record: The record to be logged.
         """
         message = super(CloudLoggingHandler, self).format(record)
-        self.transport.send(record,
-                            message,
-                            resource=self.resource,
-                            labels=self.labels)
+        self.transport.send(
+            record,
+            message,
+            resource=self.resource,
+            labels=self.labels)
 
 
 def setup_logging(handler, excluded_loggers=EXCLUDED_LOGGER_DEFAULTS,
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index be5102487cc6..92bfd4369b00 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -12,10 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-try:
-    from threading import local
-except ImportError:
-    from django.utils._threading_local import local
+from threading import local
+
 
 _thread_locals = local()
 
diff --git a/logging/tests/unit/handlers/test_app_engine.py b/logging/tests/unit/handlers/test_app_engine.py
index c39328593f7a..99f5ea93625a 100644
--- a/logging/tests/unit/handlers/test_app_engine.py
+++ b/logging/tests/unit/handlers/test_app_engine.py
@@ -34,6 +34,7 @@ def test_constructor(self):
         from google.cloud.logging.handlers.app_engine import _GAE_VERSION_ENV
 
         client = mock.Mock(project=self.PROJECT, spec=['project'])
+
         with mock.patch('os.environ', new={_GAE_PROJECT_ENV: 'test_project',
                                            _GAE_SERVICE_ENV: 'test_service',
                                            _GAE_VERSION_ENV: 'test_version'}):
@@ -43,6 +44,7 @@ def test_constructor(self):
         self.assertEqual(handler.resource.labels['project_id'], 'test_project')
         self.assertEqual(handler.resource.labels['module_id'], 'test_service')
         self.assertEqual(handler.resource.labels['version_id'], 'test_version')
+        self.assertEqual(handler.labels['appengine.googleapis.com/trace_id'], 'unknown')
 
     def test_emit(self):
         import mock
@@ -50,6 +52,7 @@ def test_emit(self):
         client = mock.Mock(project=self.PROJECT, spec=['project'])
         handler = self._make_one(client, transport=_Transport)
         gae_resource = handler.get_gae_resource()
+        gae_labels = handler.get_gae_labels()
         logname = 'app'
         message = 'hello world'
         record = logging.LogRecord(logname, logging, None, None, message,
@@ -58,7 +61,9 @@ def test_emit(self):
 
         self.assertIs(handler.transport.client, client)
         self.assertEqual(handler.transport.name, logname)
-        self.assertEqual(handler.transport.send_called_with, (record, message, gae_resource))
+        self.assertEqual(
+            handler.transport.send_called_with,
+            (record, message, gae_resource, gae_labels))
 
 
 class _Transport(object):
@@ -67,5 +72,5 @@ def __init__(self, client, name):
         self.client = client
         self.name = name
 
-    def send(self, record, message, resource):
-        self.send_called_with = (record, message, resource)
+    def send(self, record, message, resource, labels):
+        self.send_called_with = (record, message, resource, labels)
diff --git a/logging/tests/unit/handlers/test_handlers.py b/logging/tests/unit/handlers/test_handlers.py
index 05dc87631478..5459a0c10b96 100644
--- a/logging/tests/unit/handlers/test_handlers.py
+++ b/logging/tests/unit/handlers/test_handlers.py
@@ -45,7 +45,7 @@ def test_emit(self):
                                    None, None)
         handler.emit(record)
 
-        self.assertEqual(handler.transport.send_called_with, (record, message, _GLOBAL_RESOURCE))
+        self.assertEqual(handler.transport.send_called_with, (record, message, _GLOBAL_RESOURCE, None))
 
 
 class TestSetupLogging(unittest.TestCase):
@@ -110,5 +110,5 @@ class _Transport(object):
     def __init__(self, client, name):
         pass
 
-    def send(self, record, message, resource):
-        self.send_called_with = (record, message, resource)
+    def send(self, record, message, resource, labels=None):
+        self.send_called_with = (record, message, resource, labels)
diff --git a/logging/tests/unit/handlers/transports/test_background_thread.py b/logging/tests/unit/handlers/transports/test_background_thread.py
index 3e3378dcd361..b9449ce56685 100644
--- a/logging/tests/unit/handlers/transports/test_background_thread.py
+++ b/logging/tests/unit/handlers/transports/test_background_thread.py
@@ -61,9 +61,9 @@ def test_send(self):
             python_logger_name, logging.INFO,
             None, None, message, None, None)
 
-        transport.send(record, message, _GLOBAL_RESOURCE)
+        transport.send(record, message, _GLOBAL_RESOURCE, None)
 
-        transport.worker.enqueue.assert_called_once_with(record, message, _GLOBAL_RESOURCE)
+        transport.worker.enqueue.assert_called_once_with(record, message, _GLOBAL_RESOURCE, None)
 
     def test_flush(self):
         client = _Client(self.PROJECT)
@@ -287,13 +287,13 @@ def __init__(self):
         self.commit_called = False
         self.commit_count = None
 
-    def log_struct(self, info, severity=logging.INFO, resource=None):
+    def log_struct(self, info, severity=logging.INFO, resource=None, labels=None):
         from google.cloud.logging.logger import _GLOBAL_RESOURCE
 
         assert resource is None
         resource = _GLOBAL_RESOURCE
 
-        self.log_struct_called_with = (info, severity, resource)
+        self.log_struct_called_with = (info, severity, resource, labels)
         self.entries.append(info)
 
     def commit(self):
diff --git a/logging/tests/unit/handlers/transports/test_sync.py b/logging/tests/unit/handlers/transports/test_sync.py
index 475ecc9c6a71..e18920ce2167 100644
--- a/logging/tests/unit/handlers/transports/test_sync.py
+++ b/logging/tests/unit/handlers/transports/test_sync.py
@@ -52,7 +52,7 @@ def test_send(self):
             'message': message,
             'python_logger': python_logger_name,
         }
-        EXPECTED_SENT = (EXPECTED_STRUCT, 'INFO', _GLOBAL_RESOURCE)
+        EXPECTED_SENT = (EXPECTED_STRUCT, 'INFO', _GLOBAL_RESOURCE, None)
         self.assertEqual(
             transport.logger.log_struct_called_with, EXPECTED_SENT)
 
@@ -63,8 +63,8 @@ class _Logger(object):
     def __init__(self, name):
         self.name = name
 
-    def log_struct(self, message, severity=None, resource=_GLOBAL_RESOURCE):
-        self.log_struct_called_with = (message, severity, resource)
+    def log_struct(self, message, severity=None, resource=_GLOBAL_RESOURCE, labels=None):
+        self.log_struct_called_with = (message, severity, resource, labels)
 
 
 class _Client(object):

From 6fc4b21faff5ee1a231904e82304d250344c71dd Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Thu, 25 May 2017 10:45:36 -0700
Subject: [PATCH 38/47] Fix stuff

---
 .../google/cloud/logging/handlers/_helpers.py | 35 ++++++++++++++-----
 .../logging/handlers/middleware/request.py    | 17 +++++----
 .../tests/unit/handlers/test_app_engine.py    |  4 ++-
 3 files changed, 37 insertions(+), 19 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 0af7a53de476..ca94e17ebb92 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -22,7 +22,10 @@
 except ImportError:
     flask = None
 
-from google.cloud.logging.handlers.middleware.request import get_request
+from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+
+_FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
+_DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
 
 
 def format_stackdriver_json(record, message):
@@ -52,10 +55,16 @@ def get_trace_id_from_flask():
     :rtype: str
     :return: Trace_id in HTTP request headers.
     """
-    try:
-        trace_id = flask.request.headers['X_CLOUD_TRACE_CONTEXT'].split('/')[0]
-    except Exception:
-        trace_id = None
+    if not flask or not flask.request:
+        return None
+
+    header = flask.request.headers.get(_FLASK_TRACE_HEADER)
+
+    if not header:
+        return None
+
+    trace_id = header.split('/')[0]
+
     return trace_id
 
 
@@ -65,11 +74,19 @@ def get_trace_id_from_django():
     :rtype: str
     :return: Trace_id in HTTP request headers.
     """
+    request_middleware = RequestMiddleware()
+    request = request_middleware.get_request()
+
+    if not request:
+        return None
+
     try:
-        request = get_request()
-        trace_id = request.META['HTTP_X_CLOUD_TRACE_CONTEXT'].split('/')[0]
-    except Exception:
-        trace_id = None
+        header = request.META[_DJANGO_TRACE_HEADER]
+    except KeyError:
+        return None
+
+    trace_id = header.split('/')[0]
+
     return trace_id
 
 
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index 92bfd4369b00..7e0e89f6aa39 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -18,15 +18,6 @@
 _thread_locals = local()
 
 
-def get_request():
-    """Get Django request from thread local.
-
-    :rtype: str
-    :returns: Django request.
-    """
-    return getattr(_thread_locals, 'request', None)
-
-
 class RequestMiddleware(object):
     """Saves the request in thread local"""
 
@@ -37,3 +28,11 @@ def process_request(self, request):
         :param request: Django http request.
         """
         _thread_locals.request = request
+
+    def get_request(self):
+        """Get Django request from thread local.
+
+        :rtype: str
+        :returns: Django request.
+        """
+        return getattr(_thread_locals, 'request', None)
diff --git a/logging/tests/unit/handlers/test_app_engine.py b/logging/tests/unit/handlers/test_app_engine.py
index 99f5ea93625a..0f8ace3a95e7 100644
--- a/logging/tests/unit/handlers/test_app_engine.py
+++ b/logging/tests/unit/handlers/test_app_engine.py
@@ -33,6 +33,8 @@ def test_constructor(self):
         from google.cloud.logging.handlers.app_engine import _GAE_SERVICE_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_VERSION_ENV
 
+        TRACE_ID_LABEL = 'appengine.googleapis.com/trace_id'
+
         client = mock.Mock(project=self.PROJECT, spec=['project'])
 
         with mock.patch('os.environ', new={_GAE_PROJECT_ENV: 'test_project',
@@ -44,7 +46,7 @@ def test_constructor(self):
         self.assertEqual(handler.resource.labels['project_id'], 'test_project')
         self.assertEqual(handler.resource.labels['module_id'], 'test_service')
         self.assertEqual(handler.resource.labels['version_id'], 'test_version')
-        self.assertEqual(handler.labels['appengine.googleapis.com/trace_id'], 'unknown')
+        self.assertEqual(handler.labels[TRACE_ID_LABEL], 'unknown')
 
     def test_emit(self):
         import mock

From 2106bfc8bf6cdc68515f4954bbf057bc3edcfa1a Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Thu, 25 May 2017 14:54:23 -0700
Subject: [PATCH 39/47] Add unit test for flask and some refactor

---
 .../google/cloud/logging/handlers/_helpers.py | 12 ++--
 .../cloud/logging/handlers/app_engine.py      |  2 -
 logging/nox.py                                |  2 +-
 logging/tests/unit/handlers/test__helpers.py  | 57 +++++++++++++++++++
 .../tests/unit/handlers/test_app_engine.py    |  3 +-
 5 files changed, 67 insertions(+), 9 deletions(-)
 create mode 100644 logging/tests/unit/handlers/test__helpers.py

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index ca94e17ebb92..17caf76e4aa9 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -27,6 +27,8 @@
 _FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
 _DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
 
+_EMPTY_TRACE_ID = 'None'
+
 
 def format_stackdriver_json(record, message):
     """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -56,12 +58,12 @@ def get_trace_id_from_flask():
     :return: Trace_id in HTTP request headers.
     """
     if not flask or not flask.request:
-        return None
+        return _EMPTY_TRACE_ID
 
     header = flask.request.headers.get(_FLASK_TRACE_HEADER)
 
     if not header:
-        return None
+        return _EMPTY_TRACE_ID
 
     trace_id = header.split('/')[0]
 
@@ -78,12 +80,12 @@ def get_trace_id_from_django():
     request = request_middleware.get_request()
 
     if not request:
-        return None
+        return _EMPTY_TRACE_ID
 
     try:
         header = request.META[_DJANGO_TRACE_HEADER]
     except KeyError:
-        return None
+        return _EMPTY_TRACE_ID
 
     trace_id = header.split('/')[0]
 
@@ -100,7 +102,7 @@ def get_trace_id():
 
     for checker in checkers:
         trace_id = checker()
-        if trace_id is not None:
+        if trace_id is not _EMPTY_TRACE_ID:
             return trace_id
 
     return trace_id
diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index 8ebb460f23c6..ccab4101848b 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -77,8 +77,6 @@ def get_gae_labels(self):
         :returns: Labels for GAE app.
         """
         trace_id = get_trace_id()
-        if trace_id is None:
-            trace_id = 'unknown'
         gae_labels = {
             'appengine.googleapis.com/trace_id': trace_id,
         }
diff --git a/logging/nox.py b/logging/nox.py
index 5d4751a955a5..11d484b232e7 100644
--- a/logging/nox.py
+++ b/logging/nox.py
@@ -31,7 +31,7 @@ def unit_tests(session, python_version):
     session.interpreter = 'python{}'.format(python_version)
 
     # Install all test dependencies, then install this package in-place.
-    session.install('mock', 'pytest', 'pytest-cov', *LOCAL_DEPS)
+    session.install('mock', 'pytest', 'pytest-cov', 'flask', *LOCAL_DEPS)
     session.install('-e', '.')
 
     # Run py.test against the unit tests.
diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
new file mode 100644
index 000000000000..db9d51d27920
--- /dev/null
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -0,0 +1,57 @@
+# Copyright 2017 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+
+
+class TestFlaskTrace(unittest.TestCase):
+
+    def create_app(self):
+        import flask
+
+        app = flask.Flask(__name__)
+
+        @app.route('/')
+        def index():
+            return 'test flask trace'
+
+        return app
+
+    def setUp(self):
+        self.app = self.create_app()
+
+    def test_trace_id_no_context_header(self):
+        from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
+        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
+
+        with self.app.test_request_context(
+                path='/',
+                headers={}):
+            trace_id = get_trace_id_from_flask()
+
+        self.assertEqual(trace_id, _EMPTY_TRACE_ID)
+
+    def test_trace_id_valid_context_header(self):
+        from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
+
+        FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
+        FLASK_TRACE_ID = 'testtraceid/testspanid'
+
+        with self.app.test_request_context(
+                path='/',
+                headers={FLASK_TRACE_HEADER:FLASK_TRACE_ID}):
+            trace_id = get_trace_id_from_flask()
+
+        EXPECTED_TRACE_ID = 'testtraceid'
+        self.assertEqual(trace_id, EXPECTED_TRACE_ID)
diff --git a/logging/tests/unit/handlers/test_app_engine.py b/logging/tests/unit/handlers/test_app_engine.py
index 0f8ace3a95e7..886dbbbb5584 100644
--- a/logging/tests/unit/handlers/test_app_engine.py
+++ b/logging/tests/unit/handlers/test_app_engine.py
@@ -32,6 +32,7 @@ def test_constructor(self):
         from google.cloud.logging.handlers.app_engine import _GAE_PROJECT_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_SERVICE_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_VERSION_ENV
+        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
 
         TRACE_ID_LABEL = 'appengine.googleapis.com/trace_id'
 
@@ -46,7 +47,7 @@ def test_constructor(self):
         self.assertEqual(handler.resource.labels['project_id'], 'test_project')
         self.assertEqual(handler.resource.labels['module_id'], 'test_service')
         self.assertEqual(handler.resource.labels['version_id'], 'test_version')
-        self.assertEqual(handler.labels[TRACE_ID_LABEL], 'unknown')
+        self.assertEqual(handler.labels[TRACE_ID_LABEL], _EMPTY_TRACE_ID)
 
     def test_emit(self):
         import mock

From c66fc317de4595b8ed361bca17496f4d5e3fceef Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 26 May 2017 10:20:56 -0700
Subject: [PATCH 40/47] Add unit test for middleware

---
 logging/nox.py                                |  2 +-
 .../unit/handlers/middleware/test_request.py  | 39 +++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)
 create mode 100644 logging/tests/unit/handlers/middleware/test_request.py

diff --git a/logging/nox.py b/logging/nox.py
index 11d484b232e7..de975600fd04 100644
--- a/logging/nox.py
+++ b/logging/nox.py
@@ -31,7 +31,7 @@ def unit_tests(session, python_version):
     session.interpreter = 'python{}'.format(python_version)
 
     # Install all test dependencies, then install this package in-place.
-    session.install('mock', 'pytest', 'pytest-cov', 'flask', *LOCAL_DEPS)
+    session.install('mock', 'pytest', 'pytest-cov', 'flask', 'django', *LOCAL_DEPS)
     session.install('-e', '.')
 
     # Run py.test against the unit tests.
diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
new file mode 100644
index 000000000000..ad784b45c48e
--- /dev/null
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -0,0 +1,39 @@
+# Copyright 2017 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+
+
+class TestRequestMiddleware(unittest.TestCase):
+
+    def _get_target_class(self):
+        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+
+        return RequestMiddleware
+
+    def _make_one(self, *args, **kw):
+        return self._get_target_class()(*args, **kw)
+
+    def test_get_request(self):
+        from django.conf import settings
+        from django.test.utils import setup_test_environment
+        from django.test import RequestFactory
+
+        settings.configure()
+        setup_test_environment()
+
+        self.middleware = self._make_one()
+        self.request = RequestFactory().get('/')
+        self.middleware.process_request(self.request)
+        self.assertEqual(self.middleware.get_request(), self.request)

From 035c4a7be20b1705836b31b946e82c15be04487e Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 26 May 2017 11:25:41 -0700
Subject: [PATCH 41/47] Add unit test for django

---
 .../unit/handlers/middleware/test_request.py  | 15 ++++-
 logging/tests/unit/handlers/test__helpers.py  | 67 ++++++++++++++++++-
 2 files changed, 77 insertions(+), 5 deletions(-)

diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
index ad784b45c48e..5b6dfca8dc67 100644
--- a/logging/tests/unit/handlers/middleware/test_request.py
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -25,15 +25,24 @@ def _get_target_class(self):
     def _make_one(self, *args, **kw):
         return self._get_target_class()(*args, **kw)
 
-    def test_get_request(self):
+    def setUp(self):
         from django.conf import settings
         from django.test.utils import setup_test_environment
-        from django.test import RequestFactory
 
-        settings.configure()
+        if not settings.configured:
+            settings.configure()
         setup_test_environment()
 
+    def test_get_request(self):
+        from django.test import RequestFactory
+
         self.middleware = self._make_one()
         self.request = RequestFactory().get('/')
         self.middleware.process_request(self.request)
         self.assertEqual(self.middleware.get_request(), self.request)
+
+
+    def tearDown(self):
+        from django.test.utils import teardown_test_environment
+
+        teardown_test_environment()
diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
index db9d51d27920..3d023dd8f9cf 100644
--- a/logging/tests/unit/handlers/test__helpers.py
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -33,25 +33,88 @@ def setUp(self):
 
     def test_trace_id_no_context_header(self):
         from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
+        from google.cloud.logging.handlers._helpers import get_trace_id
         from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
 
         with self.app.test_request_context(
                 path='/',
                 headers={}):
             trace_id = get_trace_id_from_flask()
+            trace_id_returned = get_trace_id()
 
         self.assertEqual(trace_id, _EMPTY_TRACE_ID)
+        self.assertEqual(trace_id_returned, _EMPTY_TRACE_ID)
 
     def test_trace_id_valid_context_header(self):
         from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
+        from google.cloud.logging.handlers._helpers import get_trace_id
 
         FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
-        FLASK_TRACE_ID = 'testtraceid/testspanid'
+        FLASK_TRACE_ID = 'testtraceidflask/testspanid'
 
         with self.app.test_request_context(
                 path='/',
                 headers={FLASK_TRACE_HEADER:FLASK_TRACE_ID}):
             trace_id = get_trace_id_from_flask()
+            trace_id_returned = get_trace_id()
 
-        EXPECTED_TRACE_ID = 'testtraceid'
+        EXPECTED_TRACE_ID = 'testtraceidflask'
         self.assertEqual(trace_id, EXPECTED_TRACE_ID)
+        self.assertEqual(trace_id, trace_id_returned)
+
+
+class TestDjangoTrace(unittest.TestCase):
+
+    def setUp(self):
+        from django.conf import settings
+        from django.test.utils import setup_test_environment
+
+        if not settings.configured:
+            settings.configure()
+        setup_test_environment()
+
+    def test_trace_id_no_context_header(self):
+        import mock
+        from django.test import RequestFactory
+        from google.cloud.logging.handlers._helpers import get_trace_id_from_django
+        from google.cloud.logging.handlers._helpers import get_trace_id
+        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
+
+        request = RequestFactory().get('/')
+
+        with mock.patch(
+                'google.cloud.logging.handlers.middleware.RequestMiddleware.get_request',
+                return_value=request):
+            trace_id = get_trace_id_from_django()
+            trace_id_returned = get_trace_id()
+
+        self.assertEqual(trace_id, _EMPTY_TRACE_ID)
+        self.assertEqual(trace_id_returned, _EMPTY_TRACE_ID)
+
+    def test_trace_id_valid_context_header(self):
+        import mock
+        from django.test import RequestFactory
+        from google.cloud.logging.handlers._helpers import get_trace_id_from_django
+        from google.cloud.logging.handlers._helpers import get_trace_id
+
+        DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
+        DJANGO_TRACE_ID = 'testtraceiddjango/testspanid'
+
+        request = RequestFactory().get(
+            '/',
+            **{DJANGO_TRACE_HEADER:DJANGO_TRACE_ID})
+
+        with mock.patch(
+                'google.cloud.logging.handlers.middleware.RequestMiddleware.get_request',
+                return_value=request):
+            trace_id = get_trace_id_from_django()
+            trace_id_returned = get_trace_id()
+
+        EXPECTED_TRACE_ID = 'testtraceiddjango'
+        self.assertEqual(trace_id, EXPECTED_TRACE_ID)
+        self.assertEqual(trace_id, trace_id_returned)
+
+    def tearDown(self):
+        from django.test.utils import teardown_test_environment
+
+        teardown_test_environment()

From bd8c1b4e50a616ba5296a6f980e202cbbec38a68 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 26 May 2017 11:29:54 -0700
Subject: [PATCH 42/47] Fix style

---
 logging/tests/unit/handlers/middleware/test_request.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
index 5b6dfca8dc67..0aa950263f5d 100644
--- a/logging/tests/unit/handlers/middleware/test_request.py
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -41,7 +41,6 @@ def test_get_request(self):
         self.middleware.process_request(self.request)
         self.assertEqual(self.middleware.get_request(), self.request)
 
-
     def tearDown(self):
         from django.test.utils import teardown_test_environment
 

From 51bf1931e5656265d3e9ebc36ce102e9c63dad24 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 26 May 2017 14:38:45 -0700
Subject: [PATCH 43/47] Address jon's comments

---
 .../google/cloud/logging/handlers/_helpers.py | 17 ++---
 .../cloud/logging/handlers/app_engine.py      | 10 ++-
 .../logging/handlers/middleware/request.py    | 17 ++---
 .../unit/handlers/middleware/test_request.py  | 13 ++--
 logging/tests/unit/handlers/test__helpers.py  | 66 ++++++++++---------
 .../tests/unit/handlers/test_app_engine.py    |  6 +-
 6 files changed, 66 insertions(+), 63 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 17caf76e4aa9..2c88f427f00b 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -22,13 +22,11 @@
 except ImportError:
     flask = None
 
-from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+from google.cloud.logging.handlers.middleware.request import _get_request
 
 _FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
 _DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
 
-_EMPTY_TRACE_ID = 'None'
-
 
 def format_stackdriver_json(record, message):
     """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -58,12 +56,12 @@ def get_trace_id_from_flask():
     :return: Trace_id in HTTP request headers.
     """
     if not flask or not flask.request:
-        return _EMPTY_TRACE_ID
+        return None
 
     header = flask.request.headers.get(_FLASK_TRACE_HEADER)
 
     if not header:
-        return _EMPTY_TRACE_ID
+        return None
 
     trace_id = header.split('/')[0]
 
@@ -76,16 +74,15 @@ def get_trace_id_from_django():
     :rtype: str
     :return: Trace_id in HTTP request headers.
     """
-    request_middleware = RequestMiddleware()
-    request = request_middleware.get_request()
+    request = _get_request()
 
     if not request:
-        return _EMPTY_TRACE_ID
+        return None
 
     try:
         header = request.META[_DJANGO_TRACE_HEADER]
     except KeyError:
-        return _EMPTY_TRACE_ID
+        return None
 
     trace_id = header.split('/')[0]
 
@@ -102,7 +99,7 @@ def get_trace_id():
 
     for checker in checkers:
         trace_id = checker()
-        if trace_id is not _EMPTY_TRACE_ID:
+        if trace_id is not None:
             return trace_id
 
     return trace_id
diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index ccab4101848b..4561b83555c4 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -31,6 +31,8 @@
 _GAE_SERVICE_ENV = 'GAE_SERVICE'
 _GAE_VERSION_ENV = 'GAE_VERSION'
 
+_TRACE_ID_LABEL = 'appengine.googleapis.com/trace_id'
+
 
 class AppEngineHandler(CloudLoggingHandler):
     """A logging handler that sends App Engine-formatted logs to Stackdriver.
@@ -76,8 +78,10 @@ def get_gae_labels(self):
         :rtype: dict
         :returns: Labels for GAE app.
         """
+        gae_labels = {}
+
         trace_id = get_trace_id()
-        gae_labels = {
-            'appengine.googleapis.com/trace_id': trace_id,
-        }
+        if trace_id is not None:
+            gae_labels[_TRACE_ID_LABEL] = trace_id
+
         return gae_labels
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index 7e0e89f6aa39..9baf11f4dbbe 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -18,6 +18,15 @@
 _thread_locals = local()
 
 
+def _get_request():
+    """Get Django request from thread local.
+
+    :rtype: str
+    :returns: Django request.
+    """
+    return getattr(_thread_locals, 'request', None)
+
+
 class RequestMiddleware(object):
     """Saves the request in thread local"""
 
@@ -28,11 +37,3 @@ def process_request(self, request):
         :param request: Django http request.
         """
         _thread_locals.request = request
-
-    def get_request(self):
-        """Get Django request from thread local.
-
-        :rtype: str
-        :returns: Django request.
-        """
-        return getattr(_thread_locals, 'request', None)
diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
index 0aa950263f5d..349247805104 100644
--- a/logging/tests/unit/handlers/middleware/test_request.py
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -33,15 +33,16 @@ def setUp(self):
             settings.configure()
         setup_test_environment()
 
+    def tearDown(self):
+        from django.test.utils import teardown_test_environment
+
+        teardown_test_environment()
+
     def test_get_request(self):
         from django.test import RequestFactory
+        from google.cloud.logging.handlers.middleware.request import _get_request
 
         self.middleware = self._make_one()
         self.request = RequestFactory().get('/')
         self.middleware.process_request(self.request)
-        self.assertEqual(self.middleware.get_request(), self.request)
-
-    def tearDown(self):
-        from django.test.utils import teardown_test_environment
-
-        teardown_test_environment()
+        self.assertEqual(_get_request(), self.request)
diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
index 3d023dd8f9cf..634ceb26e8a6 100644
--- a/logging/tests/unit/handlers/test__helpers.py
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -34,7 +34,6 @@ def setUp(self):
     def test_trace_id_no_context_header(self):
         from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
         from google.cloud.logging.handlers._helpers import get_trace_id
-        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
 
         with self.app.test_request_context(
                 path='/',
@@ -42,24 +41,24 @@ def test_trace_id_no_context_header(self):
             trace_id = get_trace_id_from_flask()
             trace_id_returned = get_trace_id()
 
-        self.assertEqual(trace_id, _EMPTY_TRACE_ID)
-        self.assertEqual(trace_id_returned, _EMPTY_TRACE_ID)
+        self.assertEqual(trace_id, None)
+        self.assertEqual(trace_id_returned, None)
 
     def test_trace_id_valid_context_header(self):
         from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
         from google.cloud.logging.handlers._helpers import get_trace_id
 
-        FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
-        FLASK_TRACE_ID = 'testtraceidflask/testspanid'
+        flask_trace_header = 'X_CLOUD_TRACE_CONTEXT'
+        flask_trace_id = 'testtraceidflask/testspanid'
 
         with self.app.test_request_context(
                 path='/',
-                headers={FLASK_TRACE_HEADER:FLASK_TRACE_ID}):
+                headers={flask_trace_header:flask_trace_id}):
             trace_id = get_trace_id_from_flask()
             trace_id_returned = get_trace_id()
 
-        EXPECTED_TRACE_ID = 'testtraceidflask'
-        self.assertEqual(trace_id, EXPECTED_TRACE_ID)
+        expected_trace_id = 'testtraceidflask'
+        self.assertEqual(trace_id, expected_trace_id)
         self.assertEqual(trace_id, trace_id_returned)
 
 
@@ -73,48 +72,51 @@ def setUp(self):
             settings.configure()
         setup_test_environment()
 
+    def tearDown(self):
+        from django.test.utils import teardown_test_environment
+
+        teardown_test_environment()
+
     def test_trace_id_no_context_header(self):
-        import mock
         from django.test import RequestFactory
         from google.cloud.logging.handlers._helpers import get_trace_id_from_django
         from google.cloud.logging.handlers._helpers import get_trace_id
-        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
+        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+        from google.cloud.logging.handlers.middleware.request import _thread_locals
 
         request = RequestFactory().get('/')
 
-        with mock.patch(
-                'google.cloud.logging.handlers.middleware.RequestMiddleware.get_request',
-                return_value=request):
-            trace_id = get_trace_id_from_django()
-            trace_id_returned = get_trace_id()
+        middleware = RequestMiddleware()
+        middleware.process_request(request)
+        trace_id = get_trace_id_from_django()
+        trace_id_returned = get_trace_id()
 
-        self.assertEqual(trace_id, _EMPTY_TRACE_ID)
-        self.assertEqual(trace_id_returned, _EMPTY_TRACE_ID)
+        self.assertEqual(trace_id, None)
+        self.assertEqual(trace_id_returned, None)
+
+        _thread_locals.__dict__.clear()
 
     def test_trace_id_valid_context_header(self):
-        import mock
         from django.test import RequestFactory
         from google.cloud.logging.handlers._helpers import get_trace_id_from_django
         from google.cloud.logging.handlers._helpers import get_trace_id
+        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+        from google.cloud.logging.handlers.middleware.request import _thread_locals
 
-        DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
-        DJANGO_TRACE_ID = 'testtraceiddjango/testspanid'
+        django_trace_header = 'HTTP_X_CLOUD_TRACE_CONTEXT'
+        django_trace_id = 'testtraceiddjango/testspanid'
 
         request = RequestFactory().get(
             '/',
-            **{DJANGO_TRACE_HEADER:DJANGO_TRACE_ID})
+            **{django_trace_header:django_trace_id})
 
-        with mock.patch(
-                'google.cloud.logging.handlers.middleware.RequestMiddleware.get_request',
-                return_value=request):
-            trace_id = get_trace_id_from_django()
-            trace_id_returned = get_trace_id()
+        middleware = RequestMiddleware()
+        middleware.process_request(request)
+        trace_id = get_trace_id_from_django()
+        trace_id_returned = get_trace_id()
 
-        EXPECTED_TRACE_ID = 'testtraceiddjango'
-        self.assertEqual(trace_id, EXPECTED_TRACE_ID)
+        expected_trace_id = 'testtraceiddjango'
+        self.assertEqual(trace_id, expected_trace_id)
         self.assertEqual(trace_id, trace_id_returned)
 
-    def tearDown(self):
-        from django.test.utils import teardown_test_environment
-
-        teardown_test_environment()
+        _thread_locals.__dict__.clear()
diff --git a/logging/tests/unit/handlers/test_app_engine.py b/logging/tests/unit/handlers/test_app_engine.py
index 886dbbbb5584..ccdaf2992335 100644
--- a/logging/tests/unit/handlers/test_app_engine.py
+++ b/logging/tests/unit/handlers/test_app_engine.py
@@ -32,9 +32,7 @@ def test_constructor(self):
         from google.cloud.logging.handlers.app_engine import _GAE_PROJECT_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_SERVICE_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_VERSION_ENV
-        from google.cloud.logging.handlers._helpers import _EMPTY_TRACE_ID
-
-        TRACE_ID_LABEL = 'appengine.googleapis.com/trace_id'
+        from google.cloud.logging.handlers.app_engine import _TRACE_ID_LABEL
 
         client = mock.Mock(project=self.PROJECT, spec=['project'])
 
@@ -47,7 +45,7 @@ def test_constructor(self):
         self.assertEqual(handler.resource.labels['project_id'], 'test_project')
         self.assertEqual(handler.resource.labels['module_id'], 'test_service')
         self.assertEqual(handler.resource.labels['version_id'], 'test_version')
-        self.assertEqual(handler.labels[TRACE_ID_LABEL], _EMPTY_TRACE_ID)
+        self.assertEqual(handler.labels, {})
 
     def test_emit(self):
         import mock

From 6b90d1e3527aef66b94527ca1b285e9dd9e8d16e Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Tue, 30 May 2017 12:28:30 -0700
Subject: [PATCH 44/47] Address jon's comments

---
 logging/google/cloud/logging/handlers/_helpers.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 2c88f427f00b..00135d0fe243 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -80,10 +80,12 @@ def get_trace_id_from_django():
         return None
 
     try:
-        header = request.META[_DJANGO_TRACE_HEADER]
+        header = request.META.get(_DJANGO_TRACE_HEADER)
     except KeyError:
         return None
 
+    if not header:
+        return None
     trace_id = header.split('/')[0]
 
     return trace_id
@@ -102,4 +104,4 @@ def get_trace_id():
         if trace_id is not None:
             return trace_id
 
-    return trace_id
+    return None

From 0c6c4f6b0dc410259d0f465b3c614d08412d78f1 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 2 Jun 2017 00:28:10 -0700
Subject: [PATCH 45/47] Address all comments

---
 .../google/cloud/logging/handlers/_helpers.py | 14 ++---
 .../logging/handlers/middleware/request.py    |  6 +-
 logging/nox.py                                |  4 +-
 .../unit/handlers/middleware/test_request.py  | 18 +++---
 logging/tests/unit/handlers/test__helpers.py  | 56 +++++++++----------
 logging/tests/unit/handlers/test_handlers.py  |  4 +-
 .../transports/test_background_thread.py      |  3 +-
 .../unit/handlers/transports/test_sync.py     |  3 +-
 8 files changed, 58 insertions(+), 50 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index 00135d0fe243..e5bdabe2e388 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -22,7 +22,7 @@
 except ImportError:
     flask = None
 
-from google.cloud.logging.handlers.middleware.request import _get_request
+from google.cloud.logging.handlers.middleware.request import _get_django_request
 
 _FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
 _DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
@@ -55,12 +55,12 @@ def get_trace_id_from_flask():
     :rtype: str
     :return: Trace_id in HTTP request headers.
     """
-    if not flask or not flask.request:
+    if flask is None or not flask.request:
         return None
 
     header = flask.request.headers.get(_FLASK_TRACE_HEADER)
 
-    if not header:
+    if header is None:
         return None
 
     trace_id = header.split('/')[0]
@@ -74,9 +74,9 @@ def get_trace_id_from_django():
     :rtype: str
     :return: Trace_id in HTTP request headers.
     """
-    request = _get_request()
+    request = _get_django_request()
 
-    if not request:
+    if request is None:
         return None
 
     try:
@@ -84,7 +84,7 @@ def get_trace_id_from_django():
     except KeyError:
         return None
 
-    if not header:
+    if header is None:
         return None
     trace_id = header.split('/')[0]
 
@@ -97,7 +97,7 @@ def get_trace_id():
     :rtype: str
     :returns: Trace_id in HTTP request headers.
     """
-    checkers = [get_trace_id_from_django, get_trace_id_from_flask]
+    checkers = (get_trace_id_from_django, get_trace_id_from_flask)
 
     for checker in checkers:
         trace_id = checker()
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index 9baf11f4dbbe..1acf7ffd9961 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -12,13 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from threading import local
+import threading
 
 
-_thread_locals = local()
+_thread_locals = threading.local()
 
 
-def _get_request():
+def _get_django_request():
     """Get Django request from thread local.
 
     :rtype: str
diff --git a/logging/nox.py b/logging/nox.py
index de975600fd04..fbbbec1958c1 100644
--- a/logging/nox.py
+++ b/logging/nox.py
@@ -31,7 +31,9 @@ def unit_tests(session, python_version):
     session.interpreter = 'python{}'.format(python_version)
 
     # Install all test dependencies, then install this package in-place.
-    session.install('mock', 'pytest', 'pytest-cov', 'flask', 'django', *LOCAL_DEPS)
+    session.install(
+        'mock', 'pytest', 'pytest-cov',
+        'flask', 'django', *LOCAL_DEPS)
     session.install('-e', '.')
 
     # Run py.test against the unit tests.
diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
index 349247805104..ab8c18d1aa0e 100644
--- a/logging/tests/unit/handlers/middleware/test_request.py
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -25,7 +25,8 @@ def _get_target_class(self):
     def _make_one(self, *args, **kw):
         return self._get_target_class()(*args, **kw)
 
-    def setUp(self):
+    @classmethod
+    def setUpClass(cls):
         from django.conf import settings
         from django.test.utils import setup_test_environment
 
@@ -33,16 +34,17 @@ def setUp(self):
             settings.configure()
         setup_test_environment()
 
-    def tearDown(self):
+    @classmethod
+    def tearDownClass(cls):
         from django.test.utils import teardown_test_environment
 
         teardown_test_environment()
 
-    def test_get_request(self):
+    def test_get_django_request(self):
         from django.test import RequestFactory
-        from google.cloud.logging.handlers.middleware.request import _get_request
+        from google.cloud.logging.handlers.middleware.request import _get_django_request
 
-        self.middleware = self._make_one()
-        self.request = RequestFactory().get('/')
-        self.middleware.process_request(self.request)
-        self.assertEqual(_get_request(), self.request)
+        middleware = self._make_one()
+        request = RequestFactory().get('/')
+        middleware.process_request(request)
+        self.assertEqual(_get_django_request(), request)
diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
index 634ceb26e8a6..59e56f34524b 100644
--- a/logging/tests/unit/handlers/test__helpers.py
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -15,9 +15,10 @@
 import unittest
 
 
-class TestFlaskTrace(unittest.TestCase):
+class Test_get_trace_id_from_flask(unittest.TestCase):
 
-    def create_app(self):
+    @staticmethod
+    def create_app():
         import flask
 
         app = flask.Flask(__name__)
@@ -29,40 +30,41 @@ def index():
         return app
 
     def setUp(self):
-        self.app = self.create_app()
+        self.app = Test_get_trace_id_from_flask.create_app()
 
     def test_trace_id_no_context_header(self):
-        from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
-        from google.cloud.logging.handlers._helpers import get_trace_id
+        from google.cloud.logging.handlers import _helpers
 
         with self.app.test_request_context(
                 path='/',
                 headers={}):
-            trace_id = get_trace_id_from_flask()
-            trace_id_returned = get_trace_id()
+            trace_id = _helpers.get_trace_id_from_flask()
+            trace_id_returned = _helpers.get_trace_id()
 
-        self.assertEqual(trace_id, None)
-        self.assertEqual(trace_id_returned, None)
+        self.assertIsNone(trace_id)
+        self.assertIsNone(trace_id_returned)
 
     def test_trace_id_valid_context_header(self):
         from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
         from google.cloud.logging.handlers._helpers import get_trace_id
 
         flask_trace_header = 'X_CLOUD_TRACE_CONTEXT'
-        flask_trace_id = 'testtraceidflask/testspanid'
+        expected_trace_id = 'testtraceidflask'
+        flask_trace_id = expected_trace_id + '/testspanid'
 
-        with self.app.test_request_context(
-                path='/',
-                headers={flask_trace_header:flask_trace_id}):
+        context = self.app.test_request_context(
+            path='/',
+            headers={flask_trace_header: flask_trace_id})
+
+        with context:
             trace_id = get_trace_id_from_flask()
             trace_id_returned = get_trace_id()
 
-        expected_trace_id = 'testtraceidflask'
         self.assertEqual(trace_id, expected_trace_id)
         self.assertEqual(trace_id, trace_id_returned)
 
 
-class TestDjangoTrace(unittest.TestCase):
+class Test_get_trace_id_from_django(unittest.TestCase):
 
     def setUp(self):
         from django.conf import settings
@@ -79,22 +81,20 @@ def tearDown(self):
 
     def test_trace_id_no_context_header(self):
         from django.test import RequestFactory
-        from google.cloud.logging.handlers._helpers import get_trace_id_from_django
-        from google.cloud.logging.handlers._helpers import get_trace_id
-        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
-        from google.cloud.logging.handlers.middleware.request import _thread_locals
+        from google.cloud.logging.handlers import _helpers
+        from google.cloud.logging.handlers.middleware import request
 
-        request = RequestFactory().get('/')
+        django_request = RequestFactory().get('/')
 
-        middleware = RequestMiddleware()
-        middleware.process_request(request)
-        trace_id = get_trace_id_from_django()
-        trace_id_returned = get_trace_id()
+        middleware = request.RequestMiddleware()
+        middleware.process_request(django_request)
+        trace_id = _helpers.get_trace_id_from_django()
+        trace_id_returned = _helpers.get_trace_id()
 
-        self.assertEqual(trace_id, None)
-        self.assertEqual(trace_id_returned, None)
+        self.assertIsNone(trace_id)
+        self.assertIsNone(trace_id_returned)
 
-        _thread_locals.__dict__.clear()
+        request._thread_locals.__dict__.clear()
 
     def test_trace_id_valid_context_header(self):
         from django.test import RequestFactory
@@ -108,7 +108,7 @@ def test_trace_id_valid_context_header(self):
 
         request = RequestFactory().get(
             '/',
-            **{django_trace_header:django_trace_id})
+            **{django_trace_header: django_trace_id})
 
         middleware = RequestMiddleware()
         middleware.process_request(request)
diff --git a/logging/tests/unit/handlers/test_handlers.py b/logging/tests/unit/handlers/test_handlers.py
index 5459a0c10b96..96823b2e906d 100644
--- a/logging/tests/unit/handlers/test_handlers.py
+++ b/logging/tests/unit/handlers/test_handlers.py
@@ -45,7 +45,9 @@ def test_emit(self):
                                    None, None)
         handler.emit(record)
 
-        self.assertEqual(handler.transport.send_called_with, (record, message, _GLOBAL_RESOURCE, None))
+        self.assertEqual(
+            handler.transport.send_called_with,
+            (record, message, _GLOBAL_RESOURCE, None))
 
 
 class TestSetupLogging(unittest.TestCase):
diff --git a/logging/tests/unit/handlers/transports/test_background_thread.py b/logging/tests/unit/handlers/transports/test_background_thread.py
index b9449ce56685..f6671273b53d 100644
--- a/logging/tests/unit/handlers/transports/test_background_thread.py
+++ b/logging/tests/unit/handlers/transports/test_background_thread.py
@@ -63,7 +63,8 @@ def test_send(self):
 
         transport.send(record, message, _GLOBAL_RESOURCE, None)
 
-        transport.worker.enqueue.assert_called_once_with(record, message, _GLOBAL_RESOURCE, None)
+        transport.worker.enqueue.assert_called_once_with(
+            record, message, _GLOBAL_RESOURCE, None)
 
     def test_flush(self):
         client = _Client(self.PROJECT)
diff --git a/logging/tests/unit/handlers/transports/test_sync.py b/logging/tests/unit/handlers/transports/test_sync.py
index e18920ce2167..01c15240f3b7 100644
--- a/logging/tests/unit/handlers/transports/test_sync.py
+++ b/logging/tests/unit/handlers/transports/test_sync.py
@@ -63,7 +63,8 @@ class _Logger(object):
     def __init__(self, name):
         self.name = name
 
-    def log_struct(self, message, severity=None, resource=_GLOBAL_RESOURCE, labels=None):
+    def log_struct(self, message, severity=None,
+                   resource=_GLOBAL_RESOURCE, labels=None):
         self.log_struct_called_with = (message, severity, resource, labels)
 
 

From fe8a3d539fa927d62abf3b2c6b461112df1a2d14 Mon Sep 17 00:00:00 2001
From: Angela Li <yanhuil@google.com>
Date: Fri, 2 Jun 2017 00:34:48 -0700
Subject: [PATCH 46/47] fix style

---
 logging/tests/unit/handlers/test__helpers.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
index 59e56f34524b..c50ce0044e85 100644
--- a/logging/tests/unit/handlers/test__helpers.py
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -104,7 +104,8 @@ def test_trace_id_valid_context_header(self):
         from google.cloud.logging.handlers.middleware.request import _thread_locals
 
         django_trace_header = 'HTTP_X_CLOUD_TRACE_CONTEXT'
-        django_trace_id = 'testtraceiddjango/testspanid'
+        expected_trace_id = 'testtraceiddjango'
+        django_trace_id = expected_trace_id + '/testspanid'
 
         request = RequestFactory().get(
             '/',
@@ -115,7 +116,6 @@ def test_trace_id_valid_context_header(self):
         trace_id = get_trace_id_from_django()
         trace_id_returned = get_trace_id()
 
-        expected_trace_id = 'testtraceiddjango'
         self.assertEqual(trace_id, expected_trace_id)
         self.assertEqual(trace_id, trace_id_returned)
 

From 4dff9043012bf7f5af0071df6ff4ee5facdacb84 Mon Sep 17 00:00:00 2001
From: Danny Hermes <daniel.j.hermes@gmail.com>
Date: Fri, 2 Jun 2017 11:43:59 -0700
Subject: [PATCH 47/47] Tweaks for style / coverage / lint.

---
 .../google/cloud/logging/handlers/_helpers.py |  12 +-
 .../cloud/logging/handlers/app_engine.py      |   5 +-
 .../logging/handlers/middleware/request.py    |   6 +
 .../unit/handlers/middleware/test_request.py  |  62 ++++++++--
 logging/tests/unit/handlers/test__helpers.py  | 115 +++++++++++++-----
 .../tests/unit/handlers/test_app_engine.py    |  36 +++++-
 6 files changed, 179 insertions(+), 57 deletions(-)

diff --git a/logging/google/cloud/logging/handlers/_helpers.py b/logging/google/cloud/logging/handlers/_helpers.py
index e5bdabe2e388..8eb2434a27a0 100644
--- a/logging/google/cloud/logging/handlers/_helpers.py
+++ b/logging/google/cloud/logging/handlers/_helpers.py
@@ -19,10 +19,11 @@
 
 try:
     import flask
-except ImportError:
+except ImportError:  # pragma: NO COVER
     flask = None
 
-from google.cloud.logging.handlers.middleware.request import _get_django_request
+from google.cloud.logging.handlers.middleware.request import (
+    _get_django_request)
 
 _FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
 _DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
@@ -79,13 +80,10 @@ def get_trace_id_from_django():
     if request is None:
         return None
 
-    try:
-        header = request.META.get(_DJANGO_TRACE_HEADER)
-    except KeyError:
-        return None
-
+    header = request.META.get(_DJANGO_TRACE_HEADER)
     if header is None:
         return None
+
     trace_id = header.split('/')[0]
 
     return trace_id
diff --git a/logging/google/cloud/logging/handlers/app_engine.py b/logging/google/cloud/logging/handlers/app_engine.py
index 4561b83555c4..509bf8002fb1 100644
--- a/logging/google/cloud/logging/handlers/app_engine.py
+++ b/logging/google/cloud/logging/handlers/app_engine.py
@@ -73,7 +73,10 @@ def get_gae_resource(self):
         return gae_resource
 
     def get_gae_labels(self):
-        """Return the labels for GAE app which includes trace_id.
+        """Return the labels for GAE app.
+
+        If the trace ID can be detected, it will be included as a label.
+        Currently, no other labels are included.
 
         :rtype: dict
         :returns: Labels for GAE app.
diff --git a/logging/google/cloud/logging/handlers/middleware/request.py b/logging/google/cloud/logging/handlers/middleware/request.py
index 1acf7ffd9961..4c0b22a8e96b 100644
--- a/logging/google/cloud/logging/handlers/middleware/request.py
+++ b/logging/google/cloud/logging/handlers/middleware/request.py
@@ -12,6 +12,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+"""Django middleware helper to capture a request.
+
+The request is stored on a thread-local so that it can be
+inspected by other helpers.
+"""
+
 import threading
 
 
diff --git a/logging/tests/unit/handlers/middleware/test_request.py b/logging/tests/unit/handlers/middleware/test_request.py
index ab8c18d1aa0e..983d67129647 100644
--- a/logging/tests/unit/handlers/middleware/test_request.py
+++ b/logging/tests/unit/handlers/middleware/test_request.py
@@ -14,16 +14,10 @@
 
 import unittest
 
+import mock
 
-class TestRequestMiddleware(unittest.TestCase):
 
-    def _get_target_class(self):
-        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
-
-        return RequestMiddleware
-
-    def _make_one(self, *args, **kw):
-        return self._get_target_class()(*args, **kw)
+class DjangoBase(unittest.TestCase):
 
     @classmethod
     def setUpClass(cls):
@@ -40,11 +34,53 @@ def tearDownClass(cls):
 
         teardown_test_environment()
 
-    def test_get_django_request(self):
+
+class TestRequestMiddleware(DjangoBase):
+
+    def _get_target_class(self):
+        from google.cloud.logging.handlers.middleware import request
+
+        return request.RequestMiddleware
+
+    def _make_one(self, *args, **kw):
+        return self._get_target_class()(*args, **kw)
+
+    def test_process_request(self):
         from django.test import RequestFactory
-        from google.cloud.logging.handlers.middleware.request import _get_django_request
+        from google.cloud.logging.handlers.middleware import request
 
         middleware = self._make_one()
-        request = RequestFactory().get('/')
-        middleware.process_request(request)
-        self.assertEqual(_get_django_request(), request)
+        mock_request = RequestFactory().get('/')
+        middleware.process_request(mock_request)
+
+        django_request = request._get_django_request()
+        self.assertEqual(django_request, mock_request)
+
+
+class Test__get_django_request(DjangoBase):
+
+    @staticmethod
+    def _call_fut():
+        from google.cloud.logging.handlers.middleware import request
+
+        return request._get_django_request()
+
+    @staticmethod
+    def _make_patch(new_locals):
+        return mock.patch(
+            'google.cloud.logging.handlers.middleware.request._thread_locals',
+            new=new_locals)
+
+    def test_with_request(self):
+        thread_locals = mock.Mock(spec=['request'])
+        with self._make_patch(thread_locals):
+            django_request = self._call_fut()
+
+        self.assertIs(django_request, thread_locals.request)
+
+    def test_without_request(self):
+        thread_locals = mock.Mock(spec=[])
+        with self._make_patch(thread_locals):
+            django_request = self._call_fut()
+
+        self.assertIsNone(django_request)
diff --git a/logging/tests/unit/handlers/test__helpers.py b/logging/tests/unit/handlers/test__helpers.py
index c50ce0044e85..a69e765afa98 100644
--- a/logging/tests/unit/handlers/test__helpers.py
+++ b/logging/tests/unit/handlers/test__helpers.py
@@ -14,9 +14,17 @@
 
 import unittest
 
+import mock
+
 
 class Test_get_trace_id_from_flask(unittest.TestCase):
 
+    @staticmethod
+    def _call_fut():
+        from google.cloud.logging.handlers import _helpers
+
+        return _helpers.get_trace_id_from_flask()
+
     @staticmethod
     def create_app():
         import flask
@@ -30,24 +38,19 @@ def index():
         return app
 
     def setUp(self):
-        self.app = Test_get_trace_id_from_flask.create_app()
+        self.app = self.create_app()
 
-    def test_trace_id_no_context_header(self):
+    def test_no_context_header(self):
         from google.cloud.logging.handlers import _helpers
 
         with self.app.test_request_context(
                 path='/',
                 headers={}):
-            trace_id = _helpers.get_trace_id_from_flask()
-            trace_id_returned = _helpers.get_trace_id()
+            trace_id = self._call_fut()
 
         self.assertIsNone(trace_id)
-        self.assertIsNone(trace_id_returned)
-
-    def test_trace_id_valid_context_header(self):
-        from google.cloud.logging.handlers._helpers import get_trace_id_from_flask
-        from google.cloud.logging.handlers._helpers import get_trace_id
 
+    def test_valid_context_header(self):
         flask_trace_header = 'X_CLOUD_TRACE_CONTEXT'
         expected_trace_id = 'testtraceidflask'
         flask_trace_id = expected_trace_id + '/testspanid'
@@ -57,15 +60,19 @@ def test_trace_id_valid_context_header(self):
             headers={flask_trace_header: flask_trace_id})
 
         with context:
-            trace_id = get_trace_id_from_flask()
-            trace_id_returned = get_trace_id()
+            trace_id = self._call_fut()
 
         self.assertEqual(trace_id, expected_trace_id)
-        self.assertEqual(trace_id, trace_id_returned)
 
 
 class Test_get_trace_id_from_django(unittest.TestCase):
 
+    @staticmethod
+    def _call_fut():
+        from google.cloud.logging.handlers import _helpers
+
+        return _helpers.get_trace_id_from_django()
+
     def setUp(self):
         from django.conf import settings
         from django.test.utils import setup_test_environment
@@ -76,47 +83,91 @@ def setUp(self):
 
     def tearDown(self):
         from django.test.utils import teardown_test_environment
+        from google.cloud.logging.handlers.middleware import request
 
         teardown_test_environment()
+        request._thread_locals.__dict__.clear()
 
-    def test_trace_id_no_context_header(self):
+    def test_no_context_header(self):
         from django.test import RequestFactory
-        from google.cloud.logging.handlers import _helpers
         from google.cloud.logging.handlers.middleware import request
 
         django_request = RequestFactory().get('/')
 
         middleware = request.RequestMiddleware()
         middleware.process_request(django_request)
-        trace_id = _helpers.get_trace_id_from_django()
-        trace_id_returned = _helpers.get_trace_id()
-
+        trace_id = self._call_fut()
         self.assertIsNone(trace_id)
-        self.assertIsNone(trace_id_returned)
 
-        request._thread_locals.__dict__.clear()
-
-    def test_trace_id_valid_context_header(self):
+    def test_valid_context_header(self):
         from django.test import RequestFactory
-        from google.cloud.logging.handlers._helpers import get_trace_id_from_django
-        from google.cloud.logging.handlers._helpers import get_trace_id
-        from google.cloud.logging.handlers.middleware.request import RequestMiddleware
-        from google.cloud.logging.handlers.middleware.request import _thread_locals
+        from google.cloud.logging.handlers.middleware import request
 
         django_trace_header = 'HTTP_X_CLOUD_TRACE_CONTEXT'
         expected_trace_id = 'testtraceiddjango'
         django_trace_id = expected_trace_id + '/testspanid'
 
-        request = RequestFactory().get(
+        django_request = RequestFactory().get(
             '/',
             **{django_trace_header: django_trace_id})
 
-        middleware = RequestMiddleware()
-        middleware.process_request(request)
-        trace_id = get_trace_id_from_django()
-        trace_id_returned = get_trace_id()
+        middleware = request.RequestMiddleware()
+        middleware.process_request(django_request)
+        trace_id = self._call_fut()
 
         self.assertEqual(trace_id, expected_trace_id)
-        self.assertEqual(trace_id, trace_id_returned)
 
-        _thread_locals.__dict__.clear()
+
+class Test_get_trace_id(unittest.TestCase):
+
+    @staticmethod
+    def _call_fut():
+        from google.cloud.logging.handlers import _helpers
+
+        return _helpers.get_trace_id()
+
+    def _helper(self, django_return, flask_return):
+        django_patch = mock.patch(
+            'google.cloud.logging.handlers._helpers.get_trace_id_from_django',
+            return_value=django_return)
+        flask_patch = mock.patch(
+            'google.cloud.logging.handlers._helpers.get_trace_id_from_flask',
+            return_value=flask_return)
+
+        with django_patch as django_mock:
+            with flask_patch as flask_mock:
+                trace_id = self._call_fut()
+
+        return django_mock, flask_mock, trace_id
+
+    def test_from_django(self):
+        django_mock, flask_mock, trace_id = self._helper(
+            'test-django-trace-id', None)
+        self.assertEqual(trace_id, django_mock.return_value)
+
+        django_mock.assert_called_once_with()
+        flask_mock.assert_not_called()
+
+    def test_from_flask(self):
+        django_mock, flask_mock, trace_id = self._helper(
+            None, 'test-flask-trace-id')
+        self.assertEqual(trace_id, flask_mock.return_value)
+
+        django_mock.assert_called_once_with()
+        flask_mock.assert_called_once_with()
+
+    def test_from_django_and_flask(self):
+        django_mock, flask_mock, trace_id = self._helper(
+            'test-django-trace-id', 'test-flask-trace-id')
+        # Django wins.
+        self.assertEqual(trace_id, django_mock.return_value)
+
+        django_mock.assert_called_once_with()
+        flask_mock.assert_not_called()
+
+    def test_missing(self):
+        django_mock, flask_mock, trace_id = self._helper(None, None)
+        self.assertIsNone(trace_id)
+
+        django_mock.assert_called_once_with()
+        flask_mock.assert_called_once_with()
diff --git a/logging/tests/unit/handlers/test_app_engine.py b/logging/tests/unit/handlers/test_app_engine.py
index ccdaf2992335..6438c4abb8a0 100644
--- a/logging/tests/unit/handlers/test_app_engine.py
+++ b/logging/tests/unit/handlers/test_app_engine.py
@@ -15,8 +15,10 @@
 import logging
 import unittest
 
+import mock
 
-class TestAppEngineHandlerHandler(unittest.TestCase):
+
+class TestAppEngineHandler(unittest.TestCase):
     PROJECT = 'PROJECT'
 
     def _get_target_class(self):
@@ -28,7 +30,6 @@ def _make_one(self, *args, **kw):
         return self._get_target_class()(*args, **kw)
 
     def test_constructor(self):
-        import mock
         from google.cloud.logging.handlers.app_engine import _GAE_PROJECT_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_SERVICE_ENV
         from google.cloud.logging.handlers.app_engine import _GAE_VERSION_ENV
@@ -48,8 +49,6 @@ def test_constructor(self):
         self.assertEqual(handler.labels, {})
 
     def test_emit(self):
-        import mock
-
         client = mock.Mock(project=self.PROJECT, spec=['project'])
         handler = self._make_one(client, transport=_Transport)
         gae_resource = handler.get_gae_resource()
@@ -66,6 +65,35 @@ def test_emit(self):
             handler.transport.send_called_with,
             (record, message, gae_resource, gae_labels))
 
+    def _get_gae_labels_helper(self, trace_id):
+        get_trace_patch = mock.patch(
+            'google.cloud.logging.handlers.app_engine.get_trace_id',
+            return_value=trace_id)
+
+        client = mock.Mock(project=self.PROJECT, spec=['project'])
+        # The handler actually calls ``get_gae_labels()``.
+        with get_trace_patch as mock_get_trace:
+            handler = self._make_one(client, transport=_Transport)
+            mock_get_trace.assert_called_once_with()
+
+            gae_labels = handler.get_gae_labels()
+            self.assertEqual(mock_get_trace.mock_calls,
+                             [mock.call(), mock.call()])
+
+        return gae_labels
+
+    def test_get_gae_labels_with_label(self):
+        from google.cloud.logging.handlers import app_engine
+
+        trace_id = 'test-gae-trace-id'
+        gae_labels = self._get_gae_labels_helper(trace_id)
+        expected_labels = {app_engine._TRACE_ID_LABEL: trace_id}
+        self.assertEqual(gae_labels, expected_labels)
+
+    def test_get_gae_labels_without_label(self):
+        gae_labels = self._get_gae_labels_helper(None)
+        self.assertEqual(gae_labels, {})
+
 
 class _Transport(object):