Module: Karafka::Processing::Strategies::DlqMom

Includes:
Dlq
Included in:
AjDlqMom
Defined in:
lib/karafka/processing/strategies/dlq_mom.rb

Overview

Same as pure dead letter queue but we do not marked failed message as consumed

Constant Summary collapse

FEATURES =

Apply strategy when dlq is on with manual offset management

%i[
  dead_letter_queue
  manual_offset_management
].freeze

Instance Method Summary collapse

Methods included from Dlq

#dispatch_to_dlq, #find_skippable_message

Methods included from Default

#commit_offsets, #commit_offsets!, #handle_before_consume, #handle_before_enqueue, #handle_consume, #handle_idle, #handle_revoked, #handle_shutdown, #mark_as_consumed, #mark_as_consumed!

Methods included from Base

#handle_before_consume, #handle_before_enqueue, #handle_consume, #handle_idle, #handle_revoked, #handle_shutdown

Instance Method Details

#handle_after_consume ⇒ Object

When manual offset management is on, we do not mark anything as consumed automatically and we rely on the user to figure things out



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# File 'lib/karafka/processing/strategies/dlq_mom.rb', line 18

def handle_after_consume
  return if revoked?

  if coordinator.success?
    coordinator.pause_tracker.reset
  elsif coordinator.pause_tracker.attempt <= topic.dead_letter_queue.max_retries
    retry_after_pause
  # If we've reached number of retries that we could, we need to skip the first message
  # that was not marked as consumed, pause and continue, while also moving this message
  # to the dead topic
  else
    # We reset the pause to indicate we will now consider it as "ok".
    coordinator.pause_tracker.reset

    skippable_message, = find_skippable_message

    dispatch_to_dlq(skippable_message)

    # Save the next offset we want to go with after moving given message to DLQ
    # Without this, we would not be able to move forward and we would end up
    # in an infinite loop trying to un-pause from the message we've already processed
    # Of course, since it's a MoM a rebalance or kill, will move it back as no
    # offsets are being committed
    coordinator.seek_offset = skippable_message.offset + 1

    pause(coordinator.seek_offset, nil, false)
  end
end