Module: WaterDrop::Producer::Sync

Included in:
WaterDrop::Producer
Defined in:
lib/waterdrop/producer/sync.rb

Overview

Component for synchronous producer operations

Instance Method Summary collapse

Instance Method Details

#produce_many_sync(messages) ⇒ Array<Rdkafka::Producer::DeliveryReport>

Produces many messages to Kafka and waits for them to be delivered

Parameters:

  • messages (Array<Hash>) —

    array with messages that comply with the Contracts::Message contract

Returns:

  • (Array<Rdkafka::Producer::DeliveryReport>) —

    delivery reports

Raises:

  • (Rdkafka::RdkafkaError) —

    When adding the messages to rdkafka’s queue failed

  • (Rdkafka::Producer::WaitTimeoutError) —

    When the timeout has been reached and some handles are still pending

  • (Errors::MessageInvalidError) —

    When any of the provided messages details are invalid and the message could not be sent to Kafka



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# File 'lib/waterdrop/producer/sync.rb', line 59

def produce_many_sync(messages)
  messages = middleware.run_many(messages)
  messages.each { |message| validate_message!(message) }

  dispatched = []
  inline_error = nil

  @monitor.instrument('messages.produced_sync', producer_id: id, messages: messages) do
    # While most of the librdkafka errors are async and not inline, there are some like
    # buffer overflow that can leak in during the `#produce` itself. When this happens, we
    # still (since it's a sync mode) need to wait on deliveries of things that were
    # successfully delegated to librdkafka. To do this, we catch the inline error and we
    # wait on messages that were in the buffer to reach final state. Then if no error, we
    # check each for error and if none all good. If there was an inline error, we re-raise
    # it with the handlers in final states.
    #
    # Such flow ensures, that we never end up with handlers not being in the final states
    # for the sync flow
    begin
      with_transaction_if_transactional do
        messages.each do |message|
          dispatched << produce(message)
        end
      end
    rescue *SUPPORTED_FLOW_ERRORS => e
      inline_error = e
    end

    # This will ensure, that we have all verdicts before raising the failure, so we pass
    # all delivery handles having a final verdict
    dispatched.each { |handler| wait(handler, raise_response_error: false) }

    raise(inline_error) if inline_error

    # This will raise an error on the first error that have happened
    dispatched.each { |handler| wait(handler) }

    dispatched
  end
rescue *SUPPORTED_FLOW_ERRORS => e
  re_raised = Errors::ProduceManyError.new(dispatched, e.inspect)

  @monitor.instrument(
    'error.occurred',
    producer_id: id,
    messages: messages,
    # If it is a transactional producer nothing was successfully dispatched on error, thus
    # we never return any dispatched handlers. While those messages might have reached
    # Kafka, in transactional mode they will not be visible to consumers with correct
    # isolation level.
    dispatched: transactional? ? EMPTY_ARRAY : dispatched,
    error: re_raised,
    type: 'messages.produce_many_sync'
  )

  raise re_raised
end

#produce_sync(message) ⇒ Rdkafka::Producer::DeliveryReport

Produces a message to Kafka and waits for it to be delivered

Parameters:

Returns:

  • (Rdkafka::Producer::DeliveryReport) —

    delivery report

Raises:

  • (Rdkafka::RdkafkaError) —

    When adding the message to rdkafka’s queue failed

  • (Rdkafka::Producer::WaitTimeoutError) —

    When the timeout has been reached and the handle is still pending

  • (Errors::MessageInvalidError) —

    When provided message details are invalid and the message could not be sent to Kafka



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# File 'lib/waterdrop/producer/sync.rb', line 18

def produce_sync(message)
  message = middleware.run(message)
  validate_message!(message)

  @monitor.instrument(
    'message.produced_sync',
    producer_id: id,
    message: message
  ) do
    wait(produce(message))
  end
rescue *SUPPORTED_FLOW_ERRORS => e
  # We use this syntax here because we want to preserve the original `#cause` when we
  # instrument the error and there is no way to manually assign `#cause` value
  begin
    raise Errors::ProduceError, e.inspect
  rescue Errors::ProduceError => ex
    @monitor.instrument(
      'error.occurred',
      producer_id: id,
      message: message,
      error: ex,
      type: 'message.produce_sync'
    )

    raise ex
  end
end