Module: Datadog::Contrib::MongoDB::Patcher

Defined in:
lib/ddtrace/contrib/mongodb/patcher.rb

Overview

Patcher adds subscribers to the MongoDB driver so that each command is traced. Use the ‘Datadog::Monkey.patch_module(:mongodb)` to activate tracing for this module.

Class Method Summary collapse

Class Method Details

.add_mongo_monitoring ⇒ Object 



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# File 'lib/ddtrace/contrib/mongodb/patcher.rb', line 45

def add_mongo_monitoring
  # Subscribe to all COMMAND queries with our subscriber class
  ::Mongo::Monitoring::Global.subscribe(
    ::Mongo::Monitoring::COMMAND,
    Datadog::Contrib::MongoDB::MongoCommandSubscriber.new
  )
end

.patch ⇒ Object 



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# File 'lib/ddtrace/contrib/mongodb/patcher.rb', line 22

def patch
  # versions prior to 2.1.0 don't support the Monitoring API
  if !@patched && (defined?(::Mongo::Monitoring::Global) && \
          Gem::Version.new(::Mongo::VERSION) >= Gem::Version.new('2.1.0'))
    begin
      require 'ddtrace/pin'
      require 'ddtrace/ext/net'
      require 'ddtrace/ext/mongo'
      require 'ddtrace/ext/app_types'
      require 'ddtrace/contrib/mongodb/parsers'
      require 'ddtrace/contrib/mongodb/subscribers'

      patch_mongo_client()
      add_mongo_monitoring()

      @patched = true
    rescue StandardError => e
      Datadog::Tracer.log.error("Unable to apply MongoDB integration: #{e}")
    end
  end
  @patched
end

.patch_mongo_client ⇒ Object 



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# File 'lib/ddtrace/contrib/mongodb/patcher.rb', line 53

def patch_mongo_client
  ::Mongo::Client.class_eval do
    alias_method :initialize_without_datadog, :initialize
    Datadog::Monkey.without_warnings do
      remove_method :initialize
    end

    def initialize(*args, &blk)
      # attach the Pin instance
      initialize_without_datadog(*args, &blk)
      pin = Datadog::Pin.new(SERVICE, app: APP, app_type: Datadog::Ext::AppTypes::DB)
      pin.onto(self)
      if pin.tracer && pin.service
        pin.tracer.set_service_info(pin.service, 'mongodb', pin.app_type)
      end
    end

    def datadog_pin
      # safe-navigation to avoid crashes during each query
      return unless respond_to? :cluster
      return unless cluster.respond_to? :addresses
      return unless cluster.addresses.respond_to? :first
      Datadog::Pin.get_from(cluster.addresses.first)
    end

    def datadog_pin=(pin)
      # safe-navigation to avoid crashes during each query
      return unless respond_to? :cluster
      return unless cluster.respond_to? :addresses
      return unless cluster.addresses.respond_to? :each
      # attach the PIN to all cluster addresses. One of them is used
      # when executing a Command and it is attached to the Monitoring
      # Event instance.
      cluster.addresses.each { |x| pin.onto(x) }
    end
  end
end

.patched? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ddtrace/contrib/mongodb/patcher.rb', line 18

def patched?
  @patched
end