Add a filter plugin add_insert_ids.

README.rdoc

@@ -1,9 +1,10 @@
 = Google Cloud Logging plugin for {fluentd}[http://github.com/fluent/fluentd]
 
-fluent-plugin-google-cloud is an
-{output plugin for fluentd}[http://docs.fluentd.org/articles/output-plugin-overview]
-which sends logs to the
-{Stackdriver Logging API}[https://cloud.google.com/logging/docs/api/].
+fluent-plugin-google-cloud gem includes two plugins:
+1. An {filter plugin for fluentd}[http://docs.fluentd.org/articles/filter-plugin-overview]
+that embeds insertIds into log entries to guarantee order and uniqueness.
+2. An {output plugin for fluentd}[http://docs.fluentd.org/articles/output-plugin-overview]
+which sends logs to the {Stackdriver Logging API}[https://cloud.google.com/logging/docs/api/].
 
 This is an official Google Ruby gem.
 
@@ -12,8 +13,7 @@ This is an official Google Ruby gem.
 
 == Installation
 
-This gem is hosted at
-{RubyGems.org}[https://rubygems.org/gems/fluent-plugin-google-cloud]
+This gem is hosted at {RubyGems.org}[https://rubygems.org/gems/fluent-plugin-google-cloud]
 and can be installed using:
 
     $ gem install fluent-plugin-google-cloud
@@ -23,22 +23,31 @@ will also install and configure the gem.
 
 == Configuration
 
+To embed insertIds into log entries, specify <code>type add_insert_ids</code>
+in a {match clause}[http://docs.fluentd.org/articles/config-file#2-ldquomatchrdquo-tell-fluentd-what-to-do]
+of your Fluentd configuration file, for example:
+
+    <filter **>
+      @type add_insert_ids
+      insert_id_key my_insert_id_field_name # Optional.
+    </filter>
+
+insert_id_key can be used to customize the insertId field name.
+
 To send logs to Google Cloud Logging, specify <code>type google_cloud</code>
-in a
-{match clause}[http://docs.fluentd.org/articles/config-file#2-ldquomatchrdquo-tell-fluentd-what-to-do]
-of your fluentd configuration file, for example:
+in a {match clause}[http://docs.fluentd.org/articles/config-file#2-ldquomatchrdquo-tell-fluentd-what-to-do]
+of your Fluentd configuration file, for example:
 
     <match **>
-      type google_cloud
+      @type google_cloud
     </match>
 
-No further configuration is required. The plugin uses
+See detailed instructions on how to configure this output plugin {here}[https://cloud.google.com/logging/docs/agent/configuration#cloud-fluentd-config].
+The plugin uses
 {Google Application Default Credentials}[https://developers.google.com/identity/protocols/application-default-credentials]
-for authorization - for additional information see 
+for authorization - for additional information see
 {here}[https://cloud.google.com/logging/docs/agent/authorization].
 
-<em>The previously documented parameters auth_method, private_key_email,
-and private_key_path are removed, and can no longer be used.</em>
 
 == Copyright
 

fluent-plugin-google-cloud.gemspec

@@ -1,17 +1,16 @@
 Gem::Specification.new do |gem|
   gem.name          = 'fluent-plugin-google-cloud'
   gem.description   = <<-eos
-   Fluentd output plugin for the Stackdriver Logging API, which will make
-   logs viewable in the Developer Console's log viewer and can optionally
-   store them in Google Cloud Storage and/or BigQuery.
-   This is an official Google Ruby gem.
+   Fluentd plugins for the Stackdriver Logging API, which will make logs
+   viewable in the Developer Console's log viewer and can optionally store them
+   in Google Cloud Storage and/or BigQuery. This is an official Google Ruby gem.
 eos
-  gem.summary       = 'fluentd output plugin for the Stackdriver Logging API'
+  gem.summary       = 'fluentd plugins for the Stackdriver Logging API'
   gem.homepage      =
     'https://github.com/GoogleCloudPlatform/fluent-plugin-google-cloud'
   gem.license       = 'Apache-2.0'
   gem.version       = '0.6.23'
-  gem.authors       = ['Ling Huang', 'Igor Peshansky']
+  gem.authors       = ['Stackdriver Agent Team']
   gem.email         = ['stackdriver-agents@google.com']
   gem.required_ruby_version = Gem::Requirement.new('>= 2.2')
 

lib/fluent/plugin/filter_add_insert_ids.rb

@@ -0,0 +1,88 @@
+# Copyright 2018 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.
+
+require 'fluent/plugin/filter'
+require 'thread'
+
+module Fluent
+  module Plugin
+    # Fluentd filter plugin for adding insertIds to guarantee log entry order
+    # and uniqueness.
+    class AddInsertIdsFilter < Filter
+      Fluent::Plugin.register_filter('add_insert_ids', self)
+
+      # Constants for configuration.
+      module ConfigConstants
+        # The default field name of insertIds in the log entry.
+        DEFAULT_INSERT_ID_KEY = 'logging.googleapis.com/insertId'.freeze
+        # The character size of the insertIds. This matches the setup in the
+        # Stackdriver Logging backend.
+        INSERT_ID_SIZE = 17
+        # The characters that are allowed in the insertIds. This matches the
+        # allowed collection by the Stackdriver Logging Backend.
+        ALLOWED_CHARS = (Array(0..9) + Array('a'..'z')).freeze
+      end
+
+      include self::ConfigConstants
+
+      desc 'The field name of insertIds in the log entry.'
+      config_param :insert_id_key, :string, default: DEFAULT_INSERT_ID_KEY
+
+      # Expose attr_readers for testing.
+      attr_reader :insert_id_key
+
+      def start
+        super
+        @log = $log # rubocop:disable Style/GlobalVars
+
+        # Initiate the insertID.
+        @log.info "Started the add_insert_ids plugin with #{@insert_id_key}" \
+                  ' as the insert ID key.'
+        @insert_id = generate_insert_id
+        @log.info "Initiated the insert ID key at #{@insert_id}."
+      end
+
+      def configure(conf)
+        super
+      end
+
+      def shutdown
+        super
+      end
+
+      # rubocop:disable Style/UnusedMethodArgument
+      def filter(tag, time, record)
+        # Only generate and add an insertId field If the record is a hash and
+        # the insert ID field is not already set.
+        if record.is_a?(Hash) && !record.key?(@insert_id_key)
+          record[@insert_id_key] = increment_insert_id
+        end
+        record
+      end
+      # rubocop:enable Style/UnusedMethodArgument
+
+      private
+
+      # Generates a random string as the insertId.
+      def generate_insert_id
+        Array.new(INSERT_ID_SIZE) { ALLOWED_CHARS.sample }.join
+      end
+
+      # Increment the insertId and return the new value.
+      def increment_insert_id
+        @insert_id = @insert_id.next
+      end
+    end
+  end
+end

test/plugin/test_filter_add_insert_ids.rb

@@ -0,0 +1,91 @@
+# Copyright 2018 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.
+
+require_relative '../helper'
+
+require 'fluent/test/driver/filter'
+require 'fluent/plugin/filter_add_insert_ids'
+
+# Unit tests for filter_add_insert_ids plugin.
+class FilterAddInsertIdsTest < Test::Unit::TestCase
+  include Fluent::Plugin::AddInsertIdsFilter::ConfigConstants
+
+  CUSTOM_INSERT_ID_KEY = 'custom_insert_id_key'.freeze
+  APPLICATION_DEFAULT_CONFIG = ''.freeze
+  TEST_MESSAGE = 'test message for add_insert_ids plugin.'.freeze
+  INSERT_ID_KEY_CONFIG = %(
+    insert_id_key #{CUSTOM_INSERT_ID_KEY}
+  ).freeze
+
+  def setup
+    Fluent::Test.setup
+  end
+
+  def test_configure_insert_id_key
+    {
+      APPLICATION_DEFAULT_CONFIG => DEFAULT_INSERT_ID_KEY,
+      INSERT_ID_KEY_CONFIG => CUSTOM_INSERT_ID_KEY
+    }.each do |config, insert_id_key|
+      d = create_driver(config)
+      assert_equal insert_id_key, d.instance.insert_id_key
+    end
+  end
+
+  def test_add_insert_ids
+    total_entry_count = 1000
+    d = create_driver
+    d.run do
+      total_entry_count.times do |index|
+        d.emit(log_entry(index))
+      end
+    end
+    filtered_events = d.filtered_as_array
+
+    assert_equal total_entry_count, filtered_events.size,
+                 "#{total_entry_count} log entries after filtering is" \
+                 " expected. Only #{filtered_events.size} are detected."
+    # The expected insertId will be assigned as we scan the first log entry.
+    expected_insert_id = nil
+    filtered_events.each_with_index do |event, index|
+      assert_equal 3, event.size, "Index #{index} failed. Log event should" \
+                   ' include 3 elements: tag, time and record.'
+      record = event[2]
+      assert_true record.is_a?(Hash), "Index #{index} failed. Log record" \
+                  ' should be a hash.'
+      assert_equal index, record['id'], "Index #{index} failed."
+      assert_equal TEST_MESSAGE, record['message'], "Index #{index} failed."
+
+      # Get the first insertID.
+      expected_insert_id = record[DEFAULT_INSERT_ID_KEY] if index == 0
+      assert_equal expected_insert_id, record[DEFAULT_INSERT_ID_KEY],
+                   "Index #{index} failed."
+      expected_insert_id = expected_insert_id.next
+      assert_true record[DEFAULT_INSERT_ID_KEY] < expected_insert_id,
+                  "Index #{index} failed. #{record[DEFAULT_INSERT_ID_KEY]}" \
+                  " < #{expected_insert_id} is false."
+    end
+  end
+
+  def create_driver(conf = APPLICATION_DEFAULT_CONFIG)
+    Fluent::Test::FilterTestDriver.new(
+      Fluent::Plugin::AddInsertIdsFilter).configure(conf, true)
+  end
+
+  def log_entry(index)
+    {
+      'id' => index,
+      'message' => TEST_MESSAGE
+    }
+  end
+end