Class: Shoryuken::Fetcher

Inherits:
Object
  • Object
show all
Includes:
Celluloid, Util
Defined in:
lib/shoryuken/fetcher.rb

Constant Summary collapse

FETCH_LIMIT = 
10

Instance Method Summary collapse

Methods included from Util

#elapsed, #fire_event, #logger, #unparse_queues, #watchdog, #worker_name

Constructor Details

#initialize(manager) ⇒ Fetcher

Returns a new instance of Fetcher.



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# File 'lib/shoryuken/fetcher.rb', line 8

def initialize(manager)
  @manager = manager
end

Instance Method Details

#fetch(queue, available_processors) ⇒ Object 



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# File 'lib/shoryuken/fetcher.rb', line 24

def fetch(queue, available_processors)
  watchdog('Fetcher#fetch died') do
    started_at = Time.now

    logger.debug { "Looking for new messages in '#{queue}'" }

    begin
      batch = Shoryuken.worker_registry.batch_receive_messages?(queue)
      limit = batch ? FETCH_LIMIT : available_processors

      if (sqs_msgs = Array(receive_messages(queue, limit))).any?
        logger.debug { "Found #{sqs_msgs.size} messages for '#{queue}'" }

        if batch
          @manager.async.assign(queue, patch_sqs_msgs!(sqs_msgs))
        else
          sqs_msgs.each { |sqs_msg| @manager.async.assign(queue, sqs_msg) }
        end

        @manager.async.rebalance_queue_weight!(queue)
      else
        logger.debug { "No message found for '#{queue}'" }

        @manager.async.pause_queue!(queue)
      end

      logger.debug { "Fetcher for '#{queue}' completed in #{elapsed(started_at)} ms" }
    rescue => ex
      logger.error { "Error fetching message: #{ex}" }
      logger.error { ex.backtrace.first }
    end

    @manager.async.dispatch
  end

end

#receive_messages(queue, limit) ⇒ Object 



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# File 'lib/shoryuken/fetcher.rb', line 12

def receive_messages(queue, limit)
  # AWS limits the batch size by 10
  limit = limit > FETCH_LIMIT ? FETCH_LIMIT : limit

  options = (Shoryuken::AwsConfig.options[:receive_message] || {}).dup
  options[:max_number_of_messages] = limit
  options[:message_attribute_names] = %w(All)
  options[:attribute_names] = %w(All)

  Shoryuken::Client.queues(queue).receive_messages options
end