Flask & Django create subsegments only if in LambdaContext & Lambda E…

…nvironment (aws#138)

* Added unit tests to ensure these frameworks generate segmentby default and
subsegments if in lambda context and environment.

aws_xray_sdk/ext/django/middleware.py

@@ -5,7 +5,7 @@
 from aws_xray_sdk.core.utils import stacktrace
 from aws_xray_sdk.ext.util import calculate_sampling_decision, \
     calculate_segment_name, construct_xray_header, prepare_response_header
-from aws_xray_sdk.core.lambda_launcher import check_in_lambda
+from aws_xray_sdk.core.lambda_launcher import check_in_lambda, LambdaContext
 
 
 log = logging.getLogger(__name__)
@@ -25,10 +25,10 @@ class XRayMiddleware(object):
     def __init__(self, get_response):
 
         self.get_response = get_response
-        self.in_lambda = False
+        self.in_lambda_ctx = False
 
-        if check_in_lambda():
-            self.in_lambda = True
+        if check_in_lambda() and type(xray_recorder.context) == LambdaContext:
+            self.in_lambda_ctx = True
 
     # hooks for django version >= 1.10
     def __call__(self, request):
@@ -51,7 +51,7 @@ def __call__(self, request):
             sampling_req=sampling_req,
         )
 
-        if self.in_lambda:
+        if self.in_lambda_ctx:
             segment = xray_recorder.begin_subsegment(name)
         else:
             segment = xray_recorder.begin_segment(
@@ -83,7 +83,7 @@ def __call__(self, request):
             segment.put_http_meta(http.CONTENT_LENGTH, length)
         response[http.XRAY_HEADER] = prepare_response_header(xray_header, segment)
 
-        if self.in_lambda:
+        if self.in_lambda_ctx:
             xray_recorder.end_subsegment()
         else:
             xray_recorder.end_segment()

aws_xray_sdk/ext/flask/middleware.py

@@ -5,7 +5,7 @@
 from aws_xray_sdk.core.utils import stacktrace
 from aws_xray_sdk.ext.util import calculate_sampling_decision, \
     calculate_segment_name, construct_xray_header, prepare_response_header
-from aws_xray_sdk.core.lambda_launcher import check_in_lambda
+from aws_xray_sdk.core.lambda_launcher import check_in_lambda, LambdaContext
 
 
 class XRayMiddleware(object):
@@ -18,10 +18,10 @@ def __init__(self, app, recorder):
         self.app.before_request(self._before_request)
         self.app.after_request(self._after_request)
         self.app.teardown_request(self._handle_exception)
-        self.in_lambda = False
+        self.in_lambda_ctx = False
 
-        if check_in_lambda():
-            self.in_lambda = True
+        if check_in_lambda() and type(self._recorder.context) == LambdaContext:
+            self.in_lambda_ctx = True
 
         _patch_render(recorder)
 
@@ -44,7 +44,7 @@ def _before_request(self):
             sampling_req=sampling_req,
         )
 
-        if self.in_lambda:
+        if self.in_lambda_ctx:
             segment = self._recorder.begin_subsegment(name)
         else:
             segment = self._recorder.begin_segment(
@@ -67,7 +67,7 @@ def _before_request(self):
             segment.put_http_meta(http.CLIENT_IP, req.remote_addr)
 
     def _after_request(self, response):
-        if self.in_lambda:
+        if self.in_lambda_ctx:
             segment = self._recorder.current_subsegment()
         else:
             segment = self._recorder.current_segment()
@@ -81,7 +81,7 @@ def _after_request(self, response):
         if cont_len:
             segment.put_http_meta(http.CONTENT_LENGTH, int(cont_len))
 
-        if self.in_lambda:
+        if self.in_lambda_ctx:
             self._recorder.end_subsegment()
         else:
             self._recorder.end_segment()
@@ -92,7 +92,7 @@ def _handle_exception(self, exception):
             return
         segment = None
         try:
-            if self.in_lambda:
+            if self.in_lambda_ctx:
                 segment = self._recorder.current_subsegment()
             else:
                 segment = self._recorder.current_segment()
@@ -104,7 +104,7 @@ def _handle_exception(self, exception):
         segment.put_http_meta(http.STATUS, 500)
         stack = stacktrace.get_stacktrace(limit=self._recorder._max_trace_back)
         segment.add_exception(exception, stack)
-        if self.in_lambda:
+        if self.in_lambda_ctx:
             self._recorder.end_subsegment()
         else:
             self._recorder.end_segment()

tests/ext/django/test_middleware.py

@@ -5,7 +5,7 @@
 
 from aws_xray_sdk.core import xray_recorder, lambda_launcher
 from aws_xray_sdk.core.context import Context
-from aws_xray_sdk.core.models import http, facade_segment
+from aws_xray_sdk.core.models import http, facade_segment, segment
 from tests.util import get_new_stubbed_recorder
 import os
 
@@ -132,3 +132,10 @@ def test_lambda_serverless(self):
         self.client.get(url)
         segment = new_recorder.emitter.pop()
         assert not segment
+
+    def test_lambda_default_ctx(self):
+        # Track to make sure that Django will default to generating segments if context is not the lambda context
+        url = reverse('200ok')
+        self.client.get(url)
+        cur_segment = xray_recorder.emitter.pop()
+        assert type(cur_segment) == segment.Segment

tests/ext/flask/test_flask.py

@@ -5,7 +5,7 @@
 from aws_xray_sdk.ext.flask.middleware import XRayMiddleware
 from aws_xray_sdk.core.context import Context
 from aws_xray_sdk.core import lambda_launcher
-from aws_xray_sdk.core.models import http, facade_segment
+from aws_xray_sdk.core.models import http, facade_segment, segment
 from tests.util import get_new_stubbed_recorder
 import os
 
@@ -186,7 +186,7 @@ def trace_header():
         return 'ok'
 
     middleware = XRayMiddleware(new_app, new_recorder)
-    middleware.in_lambda = True
+    middleware.in_lambda_ctx = True
 
     app_client = new_app.test_client()
 
@@ -197,3 +197,31 @@ def trace_header():
 
     path2 = '/trace_header'
     app_client.get(path2, headers={http.XRAY_HEADER: 'k1=v1'})
+
+
+def test_lambda_default_ctx():
+    # Track to make sure that Flask will default to generating segments if context is not the lambda context
+    TRACE_ID = '1-5759e988-bd862e3fe1be46a994272793'
+    PARENT_ID = '53995c3f42cd8ad8'
+    HEADER_VAR = "Root=%s;Parent=%s;Sampled=1" % (TRACE_ID, PARENT_ID)
+
+    os.environ[lambda_launcher.LAMBDA_TRACE_HEADER_KEY] = HEADER_VAR
+
+    new_recorder = get_new_stubbed_recorder()
+    new_recorder.configure(service='test', sampling=False)
+    new_app = Flask(__name__)
+
+    @new_app.route('/segment')
+    def subsegment():
+        # Test in between request and make sure Lambda that uses default context generates a segment.
+        assert new_recorder.current_segment()
+        assert type(new_recorder.current_segment()) == segment.Segment
+        return 'ok'
+
+    XRayMiddleware(new_app, new_recorder)
+    app_client = new_app.test_client()
+
+    path = '/segment'
+    app_client.get(path)
+    segment = recorder.emitter.pop()
+    assert not segment  # Segment should be none because it's created and ended by the middleware