Module: Kafka::Tracer

Defined in:
lib/kafka/tracer.rb,
lib/kafka/tracer/version.rb

Defined Under Namespace

Classes: IncompatibleGemVersion

Constant Summary collapse

IngoreMessage = 
->(_value, _key, _headers, _topic, _partition, _partition_key) { false }
VERSION = 
'0.4.0'

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.ignore_message ⇒ Object

Returns the value of attribute ignore_message.



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# File 'lib/kafka/tracer.rb', line 11

def ignore_message
  @ignore_message
end

.tracer ⇒ Object

Returns the value of attribute tracer.



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# File 'lib/kafka/tracer.rb', line 11

def tracer
  @tracer
end

Class Method Details

.compatible_version? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/kafka/tracer.rb', line 31

def compatible_version?
  # https://github.com/zendesk/ruby-kafka/pull/604
  Gem::Version.new(Kafka::VERSION) >= Gem::Version.new("0.7.0")
end

.instrument(tracer: OpenTracing.global_tracer, ignore_message: IngoreMessage) ⇒ Object

Raises:



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# File 'lib/kafka/tracer.rb', line 15

def instrument(tracer: OpenTracing.global_tracer, ignore_message: IngoreMessage)
  begin
    require 'kafka'
  rescue LoadError
    return
  end
  raise IncompatibleGemVersion unless compatible_version?

  @ignore_message = ignore_message
  @tracer = tracer
  patch_producer_produce
  patch_client_deliver_message
  patch_client_each_message
  patch_consumer_each_message
end

.patch_client_deliver_message ⇒ Object

used to send sync messages



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# File 'lib/kafka/tracer.rb', line 71

def patch_client_deliver_message
  ::Kafka::Client.class_eval do
    alias_method :deliver_message_original, :deliver_message

    def deliver_message(value, key: nil, headers: {}, topic:, partition: nil, partition_key: nil, retries: 1)
      if ::Kafka::Tracer.ignore_message.call(value, key, headers, topic, partition, partition_key)
        result = deliver_message_original(value,
                                          key: key,
                                          headers: headers,
                                          topic: topic,
                                          partition: partition,
                                          partition_key: partition_key,
                                          retries: retries)
      else
        tags = {
          'component' => 'ruby-kafka',
          'span.kind' => 'producer',
          'message_bus.partition' => partition,
          'message_bus.partition_key' => partition_key,
          'message_bus.destination' => topic,
          'message_bus.pending_message' => false
        }

        tracer = ::Kafka::Tracer.tracer

        tracer.start_active_span('kafka.producer', tags: tags) do |scope|
          OpenTracing.inject(scope.span.context, OpenTracing::FORMAT_TEXT_MAP, headers)

          begin
            result = deliver_message_original(value,
                                              key: key,
                                              headers: headers,
                                              topic: topic,
                                              partition: partition,
                                              partition_key: partition_key,
                                              retries: retries)
          rescue Kafka::Error => e
            scope.span.set_tag('error', true)
            raise
          end
        end
      end

      result
    end
  end
end

.patch_client_each_message ⇒ Object 



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# File 'lib/kafka/tracer.rb', line 177

def patch_client_each_message
  ::Kafka::Client.class_eval do
    alias_method :each_message_original, :each_message

    def each_message(topic:, start_from_beginning: true, max_wait_time: 5, min_bytes: 1, max_bytes: 1_048_576, &block)
      tracer = ::Kafka::Tracer.tracer

      wrapped_block = lambda { |message|
        context = tracer.extract(OpenTracing::FORMAT_TEXT_MAP, message.headers)

        tags = {
          'component' => 'ruby-kafka',
          'span.kind' => 'consumer',
          'message_bus.partition' => message.partition,
          'message_bus.destination' => message.topic,
          'message_bus.pre_fetched_in_batch' => true
        }

        reference = OpenTracing::Reference.follows_from(context)

        tracer.start_active_span('kafka.consumer', references: [reference], tags: tags) do |scope|
          begin
            block.call(message)
          rescue StandardError
            scope.span.set_tag('error', true)
            raise
          end
        end
      }

      each_message_original(
        topic: topic,
        start_from_beginning: start_from_beginning,
        max_wait_time: max_wait_time,
        min_bytes: min_bytes,
        max_bytes: max_bytes,
        &wrapped_block
      )
    end
  end
end

.patch_consumer_each_message ⇒ Object 



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# File 'lib/kafka/tracer.rb', line 219

def patch_consumer_each_message
  ::Kafka::Consumer.class_eval do
    alias_method :each_message_original, :each_message

    def each_message(min_bytes: 1, max_bytes: 10485760, max_wait_time: 1, automatically_mark_as_processed: true)
      tracer = ::Kafka::Tracer.tracer

      wrapped_block = lambda { |message|
        context = tracer.extract(OpenTracing::FORMAT_TEXT_MAP, message.headers)

        tags = {
          'component' => 'ruby-kafka',
          'span.kind' => 'consumer',
          'message_bus.partition' => message.partition,
          'message_bus.destination' => message.topic,
          'message_bus.pre_fetched_in_batch' => true
        }

        reference = OpenTracing::Reference.follows_from(context)

        tracer.start_active_span('kafka.consumer', references: [reference], tags: tags) do |scope|
          begin
            yield message
          rescue StandardError
            scope.span.set_tag('error', true)
            raise
          end
        end
      }

      each_message_original(
        min_bytes: min_bytes,
        max_bytes: max_bytes,
        max_wait_time: max_wait_time,
        automatically_mark_as_processed: automatically_mark_as_processed,
        &wrapped_block
      )
    end
  end
end

.patch_deliver_messages ⇒ Object

TODO



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# File 'lib/kafka/tracer.rb', line 175

def patch_deliver_messages; end

.patch_producer_produce ⇒ Object

used to send a batch of messages



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# File 'lib/kafka/tracer.rb', line 120

def patch_producer_produce
  ::Kafka::Producer.class_eval do
    alias_method :produce_original, :produce

    def produce(value, key: nil, headers: {}, topic:, partition: nil, partition_key: nil, create_time: Time.now)

      if ::Kafka::Tracer.ignore_message.call(value, key, headers, topic, partition, partition_key)
        result = produce_original(
          value,
          key: key,
          headers: headers,
          topic: topic,
          partition: partition,
          partition_key: partition_key,
          create_time: create_time
        )

      else
        tags = {
          'component' => 'ruby-kafka',
          'span.kind' => 'producer',
          'message_bus.partition' => partition,
          'message_bus.partition_key' => partition_key,
          'message_bus.destination' => topic,
          'message_bus.pending_message' => true
        }

        tracer = ::Kafka::Tracer.tracer

        tracer.start_active_span('kafka.producer', tags: tags) do |scope|
          OpenTracing.inject(scope.span.context, OpenTracing::FORMAT_TEXT_MAP, headers)

          begin
            result = produce_original(
              value,
              key: key,
              headers: headers,
              topic: topic,
              partition: partition,
              partition_key: partition_key,
              create_time: create_time
            )
          rescue Kafka::Error => e
            scope.span.set_tag('error', true)
            raise
          end
        end
      end

      result
    end
  end
end

.remove ⇒ Object 



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# File 'lib/kafka/tracer.rb', line 36

def remove
  if ::Kafka::Producer.method_defined?(:produce_original)
    ::Kafka::Producer.class_eval do
      remove_method :produce
      alias_method :produce, :produce_original
      remove_method :produce_original
    end
  end

  if ::Kafka::Client.method_defined?(:deliver_message_original)
    ::Kafka::Client.class_eval do
      remove_method :deliver_message
      alias_method :deliver_message, :deliver_message_original
      remove_method :deliver_message_original
    end
  end

  if ::Kafka::Client.method_defined?(:each_message_original)
    ::Kafka::Client.class_eval do
      remove_method :each_message
      alias_method :each_message, :each_message_original
      remove_method :each_message_original
    end
  end

  if ::Kafka::Consumer.method_defined?(:each_message_original)
    ::Kafka::Consumer.class_eval do
      remove_method :each_message
      alias_method :each_message, :each_message_original
      remove_method :each_message_original
    end
  end
end