sidekiq.rb

class QuitWhenEmpty
  def initialize(options = nil)
  end

  def call(worker, msg, queue)
    yield
    stop_disposible_worker_if_queue_empty!
  end

  def stop_disposible_worker_if_queue_empty!
    if kill_when_queue_empty?
      Rails.logger.info "Shutting down because queue is empty"
      my_process.stop! if queue_empty?
    end
  end

  private

  def kill_when_queue_empty?
    true
  end

  def my_process
    ps = Sidekiq::ProcessSet.new
    ps.detect {|p| Process.pid == p['pid']}
  end

  def queue_empty?
    Sidekiq::Queue.new.size == 0
  end

  def self.stop_if_queue_empty
    Thread.new do
      sleep 120
      QuitWhenEmpty.new.stop_disposible_worker_if_queue_empty!
    end
  end
end

Sidekiq.configure_server do |config|
  config.server_middleware do |chain|
    QuitWhenEmpty.stop_if_queue_empty
    chain.add QuitWhenEmpty
  end
end