Module: Karafka::Pro::Processing::Strategies::Aj::DlqFtrMom

Includes:
Dlq::FtrMom
Included in:
DlqFtrMomVp
Defined in:
lib/karafka/pro/processing/strategies/aj/dlq_ftr_mom.rb

Overview

  • Aj

  • Dlq

  • Ftr

  • Mom

Constant Summary collapse

FEATURES =

Features for this strategy

%i[
  active_job
  dead_letter_queue
  filtering
  manual_offset_management
].freeze

Instance Method Summary collapse

Methods included from Dlq::FtrMom

#mark_after_dispatch?

Methods included from Dlq::Default

#apply_dlq_flow, #build_dlq_message, #dispatch_if_needed_and_mark_as_consumed, #dispatch_in_a_transaction?, #dispatch_to_dlq, #dispatch_to_dlq?, #find_skippable_message, #mark_after_dispatch?, #mark_as_consumed, #mark_as_consumed!, #mark_dispatched_to_dlq

Methods included from Default

#handle_before_consume, #handle_before_schedule_consume, #handle_before_schedule_tick, #handle_consume, #handle_revoked, #handle_tick, #mark_as_consumed, #mark_as_consumed!, #mark_in_transaction, #store_offset_metadata, #transaction

Methods included from Karafka::Processing::Strategies::Default

#commit_offsets, #commit_offsets!, #handle_before_consume, #handle_consume, #handle_eofed, #handle_idle, #handle_initialized, #handle_revoked, #handle_shutdown, #mark_as_consumed, #mark_as_consumed!

Methods included from Karafka::Processing::Strategies::Base

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

Methods included from Ftr::Default

#handle_idle, #handle_post_filtering

Instance Method Details

#handle_after_consume ⇒ Object

We write our own custom handler for after consume here, because we mark as consumed per each job in the AJ consumer itself (for this strategy). This means, that for DLQ dispatch, we can mark this message as consumed as well.



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# File 'lib/karafka/pro/processing/strategies/aj/dlq_ftr_mom.rb', line 37

def handle_after_consume
  coordinator.on_finished do
    return if revoked?

    if coordinator.success?
      coordinator.pause_tracker.reset

      return if coordinator.manual_pause?

      handle_post_filtering
    # 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.
    #
    # For a Mom setup, this means, that user has to manage the checkpointing by
    # himself. If no checkpointing is ever done, we end up with an endless loop.
    else
      apply_dlq_flow do
        skippable_message, = find_skippable_message
        dispatch_to_dlq(skippable_message) if dispatch_to_dlq?
        # We can commit the offset here because we know that we skip it "forever" and
        # since AJ consumer commits the offset after each job, we also know that the
        # previous job was successful
        mark_dispatched_to_dlq(skippable_message)
      end
    end
  end
end