Module: Eventsimple::Outbox::Consumer

Defined in:
lib/eventsimple/outbox/consumer.rb

Defined Under Namespace

Classes: ExitError

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.extended(klass) ⇒ Object 



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# File 'lib/eventsimple/outbox/consumer.rb', line 11

def self.extended(klass)
  klass.class_exec do
    class_attribute :_event_klass
    class_attribute :_identifier
    class_attribute :_processor_klass
    class_attribute :_processor_pool
    class_attribute :_concurrency, default: 5
    class_attribute :_batch_size, default: 1000
    class_attribute :stop_consumer, default: false
  end
end

Instance Method Details

#consumes_event(event_klass) ⇒ Object 



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# File 'lib/eventsimple/outbox/consumer.rb', line 27

def consumes_event(event_klass)
  event_klass._outbox_enabled = true

  self._event_klass = event_klass
end

#identifier(name) ⇒ Object 



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# File 'lib/eventsimple/outbox/consumer.rb', line 23

def identifier(name)
  self._identifier = name
end

#processor(processor_klass, concurrency: 5) ⇒ Object 



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# File 'lib/eventsimple/outbox/consumer.rb', line 33

def processor(processor_klass, concurrency: 5)
  self._concurrency = concurrency
  self._processor_klass = processor_klass
  self._processor_pool = _concurrency.times.map { processor_klass.new }
end

#run_consumer ⇒ Object 



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# File 'lib/eventsimple/outbox/consumer.rb', line 52

def run_consumer
  raise 'Eventsimple: No event class defined' unless _event_klass
  raise 'Eventsimple: No processor defined' unless _processor_klass
  raise 'Eventsimple: No identifier defined' unless _identifier
  raise 'Eventsimple: No concurrency defined' unless _concurrency.is_a?(Integer)

  $stdout.puts("Starting consumer for #{_identifier}")

  cursor = Outbox::Cursor.fetch(_identifier)

  until stop_consumer
    _event_klass.unscoped.in_batches(start: cursor + 1, load: true, of: _batch_size).each do |batch|
      grouped_events = batch.group_by { |event| event.aggregate_id.unpack1('L') % _concurrency }

      promises = grouped_events.map { |index, events|
        Concurrent::Promises.future {
          events.each do |event|
            _processor_pool[index].call(event)
            raise ExitError if stop_consumer
          end
        }
      }

      Concurrent::Promises.zip(*promises).value!

      cursor = batch.last.id
      Outbox::Cursor.set(_identifier, cursor)
    end

    sleep(1)
  end
rescue ExitError
  $stdout.puts("Stopping consumer for #{_identifier}")
end

#start ⇒ Object

rubocop:disable Metrics/AbcSize



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# File 'lib/eventsimple/outbox/consumer.rb', line 39

def start # rubocop:disable Metrics/AbcSize
  Signal.trap('INT') do
    self.stop_consumer = true
    $stdout.puts('INT received, stopping consumer')
  end
  Signal.trap('TERM') do
    self.stop_consumer = true
    $stdout.puts('TERM received, stopping consumer')
  end

  run_consumer
end