Class: Deimos::Utils::SeekListener

Inherits:
Phobos::Listener
  • Object
show all
Defined in:
lib/deimos/utils/inline_consumer.rb

Overview

Listener that can seek to get the last X messages in a topic.

Constant Summary collapse

MAX_SEEK_RETRIES = 
3

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#num_messages ⇒ Object

Returns the value of attribute num_messages.



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# File 'lib/deimos/utils/inline_consumer.rb', line 10

def num_messages
  @num_messages
end

Instance Method Details

#start_listener ⇒ Object

:nodoc:



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# File 'lib/deimos/utils/inline_consumer.rb', line 13

def start_listener
  @num_messages ||= 10
  @consumer = create_kafka_consumer
  @consumer.subscribe(topic, @subscribe_opts)
  attempt = 0

  begin
    attempt += 1
    last_offset = @kafka_client.last_offset_for(topic, 0)
    offset = last_offset - num_messages
    if offset.positive?
      Deimos.config.logger.info("Seeking to #{offset}")
      @consumer.seek(topic, 0, offset)
    end
  rescue StandardError => e
    if attempt < MAX_SEEK_RETRIES
      sleep(1.seconds * attempt)
      retry
    end
    log_error("Could not seek to offset: #{e.message} after #{MAX_SEEK_RETRIES} retries", listener_metadata)
  end

  instrument('listener.start_handler', listener_metadata) do
    @handler_class.start(@kafka_client)
  end
  log_info('Listener started', listener_metadata)
end