Merge pull request #263 from instana/hm/mongodb

Support tracing MongoDb

Author: hmadison

.circleci/config.yml

@@ -15,6 +15,7 @@ executors:
         command: ["server", "/data"]
       - image: s12v/sns
       - image: softwaremill/elasticmq-native
+      - image: circleci/mongo:5-focal-ram
   ruby_26:
     docker:
       - image: circleci/ruby:2.6-node
@@ -29,6 +30,7 @@ executors:
         command: ["server", "/data"]
       - image: s12v/sns
       - image: softwaremill/elasticmq-native
+      - image: circleci/mongo:5-focal-ram
   ruby_27:
     docker:
       - image: circleci/ruby:2.7-node
@@ -43,6 +45,7 @@ executors:
         command: ["server", "/data"]
       - image: s12v/sns
       - image: softwaremill/elasticmq-native
+      - image: circleci/mongo:5-focal-ram
   ruby_25_mysql2:
     docker:
       - image: circleci/ruby:2.5-node
@@ -280,6 +283,7 @@ workflows:
                 - "./gemfiles/sidekiq_50.gemfile"
                 - "./gemfiles/sinatra_14.gemfile"
                 - "./gemfiles/shoryuken_50.gemfile"
+                - "./gemfiles/mongo_216.gemfile"
   rails:
     jobs:
       - test_apprisal:

Appraisals

@@ -13,7 +13,7 @@ appraise 'cuba-30' do
   gem 'cuba', '>= 3.0', '< 4.0'
 end
 
-appraise 'dalli-20' do 
+appraise 'dalli-20' do
   gem 'dalli', '>= 2.0', '< 3.0'
 end
 
@@ -69,7 +69,7 @@ appraise 'rails-60' do
   gem 'sqlite3', '~> 1.4'
 end
 
-appraise 'redis-40' do 
+appraise 'redis-40' do
   gem 'redis', '>= 4.0.0', '< 5.0'
 end
 
@@ -87,7 +87,7 @@ appraise 'resque-122' do
 end
 
 appraise 'resque-20' do
-gem 'resque', '>= 2.0', '< 3.0'
+  gem 'resque', '>= 2.0', '< 3.0'
 end
 
 appraise 'roda-20' do
@@ -118,3 +118,7 @@ end
 appraise 'sidekiq-50' do
   gem 'sidekiq', '>= 5.0', '< 6.0'
 end
+
+appraise 'mongo-216' do
+  gem 'mongo', '>= 2.16', '< 3'
+end

gemfiles/mongo_216.gemfile

@@ -0,0 +1,18 @@
+# This file was generated by Appraisal
+
+# (c) Copyright IBM Corp. 2021
+# (c) Copyright Instana Inc. 2021
+
+source "https://rubygems.org"
+
+gem "rake"
+gem "minitest", "5.9.1"
+gem "minitest-reporters"
+gem "webmock"
+gem "puma"
+gem "rubocop", "~> 1.9"
+gem "rack-test"
+gem "simplecov", "~> 0.21.2"
+gem "mongo", ">= 2.16", "< 3"
+
+gemspec path: "../"

lib/instana/activators/mongo.rb

@@ -0,0 +1,23 @@
+# (c) Copyright IBM Corp. 2021
+# (c) Copyright Instana Inc. 2021
+
+module Instana
+  module Activators
+    class Mongo < Activator
+      def can_instrument?
+        defined?(::Mongo::Client) && defined?(::Mongo::Monitoring::Global)
+      end
+
+      def instrument
+        require 'instana/instrumentation/mongo'
+
+        ::Mongo::Monitoring::Global.subscribe(
+          ::Mongo::Monitoring::COMMAND,
+          ::Instana::Mongo.new
+        )
+
+        true
+      end
+    end
+  end
+end

lib/instana/instrumentation/mongo.rb

@@ -0,0 +1,46 @@
+# (c) Copyright IBM Corp. 2021
+# (c) Copyright Instana Inc. 2021
+
+module Instana
+  class Mongo
+    REMOVED_COMMAND_ELEMENTS = %w[lsid $db documents].freeze
+
+    def initialize
+      @requests = {}
+    end
+
+    def started(event)
+      tags = {
+        namespace: event.database_name,
+        command: event.command_name,
+        peer: {
+          hostname: event.address.host,
+          port: event.address.port
+        },
+        json: filter_statement(event.command)
+      }
+
+      @requests[event.request_id] = ::Instana.tracer.log_async_entry(:mongo, {mongo: tags})
+    end
+
+    def failed(event)
+      span = @requests.delete(event.request_id)
+      span.add_error(Exception.new(event.message))
+
+      ::Instana.tracer.log_async_exit(:mongo, {}, span)
+    end
+
+    def succeeded(event)
+      span = @requests.delete(event.request_id)
+      ::Instana.tracer.log_async_exit(:mongo, {}, span)
+    end
+
+    private
+
+    def filter_statement(command)
+      command.delete_if { |k, _| REMOVED_COMMAND_ELEMENTS.include?(k) }
+
+      JSON.dump(command)
+    end
+  end
+end

lib/instana/tracing/span.rb

@@ -7,12 +7,12 @@ class Span
                          :memcache, :'net-http', :rack, :render, :'rpc-client',
                          :'rpc-server', :'sidekiq-client', :'sidekiq-worker',
                          :redis, :'resque-client', :'resque-worker', :'graphql.server', :dynamodb, :s3, :sns, :sqs, :'aws.lambda.entry', :activejob, :log, :"mail.actionmailer",
-                         :"aws.lambda.invoke"  ].freeze
+                         :"aws.lambda.invoke", :mongo  ].freeze
     ENTRY_SPANS = [ :rack, :'resque-worker', :'rpc-server', :'sidekiq-worker', :'graphql.server', :sqs,
                     :'aws.lambda.entry' ].freeze
     EXIT_SPANS = [ :activerecord, :excon, :'net-http', :'resque-client',
                    :'rpc-client', :'sidekiq-client', :redis, :dynamodb, :s3, :sns, :sqs, :log, :"mail.actionmailer",
-                   :"aws.lambda.invoke" ].freeze
+                   :"aws.lambda.invoke", :mongo ].freeze
     HTTP_SPANS = [ :rack, :excon, :'net-http' ].freeze
 
     attr_accessor :parent
@@ -120,7 +120,7 @@ def add_error(e)
         elsif @data[:n] == :activerecord
           @data[:data][:activerecord][:error] = e.message
         else
-          log(:error, Time.now, { :message => e.message, :parameters => e.class.to_s })
+          log(:error, Time.now, message: e.message, parameters: e.class.to_s)
         end
         e.instance_variable_set(:@instana_logged, true)
       end

lib/instana/tracing/span_context.rb

@@ -47,7 +47,7 @@ def trace_state_header
         state.unshift("in=#{trace_id_header};#{span_id_header}")
       end
 
-      state.reject { |v| v.nil? }.join(',')
+      state.take(32).reject { |v| v.nil? }.join(',')
     end
 
     def to_hash

test/instrumentation/mongo_test.rb

@@ -0,0 +1,37 @@
+# (c) Copyright IBM Corp. 2021
+# (c) Copyright Instana Inc. 2021
+
+require 'test_helper'
+
+class MongoTest < Minitest::Test
+  def setup
+    clear_all!
+  end
+
+  def test_mongo
+    Instana.tracer.start_or_continue_trace(:'mongo-test') do
+      client = Mongo::Client.new('mongodb://127.0.0.1:27017/instana')
+      client[:people].delete_many({ name: /$S*/ })
+      client[:people].insert_many([{ _id: 1, name: "Stan" }])
+    end
+
+    spans = ::Instana.processor.queued_spans
+    delete_span, insert_span, = spans
+
+    delete_data = delete_span[:data][:mongo]
+    insert_data = insert_span[:data][:mongo]
+
+    assert_equal delete_span[:n], :mongo
+    assert_equal insert_span[:n], :mongo
+
+    assert_equal delete_data[:namespace], "instana"
+    assert_equal delete_data[:command], "delete"
+    assert_equal delete_data[:peer], {hostname: "127.0.0.1", port: 27017}
+    assert delete_data[:json].include?("delete")
+
+    assert_equal insert_data[:namespace], "instana"
+    assert_equal insert_data[:command], "insert"
+    assert_equal insert_data[:peer], {hostname: "127.0.0.1", port: 27017}
+    assert insert_data[:json].include?("insert")
+  end
+end