gistfile1.rb

require 'thread'

# in an initializer or something

class WorkerPool
  NUM_THREADS = 5
  STOP = 0x666

  def initialize
    @q = Queue.new
    @threads = []
  end

  def start
    NUM_THREADS.times do
      @threads << Thread.new do
        while true do
          job, websocket = @q.pop
          break if job == STOP
          do_work(job, websocket)
        end
      end
    end
  end

  def stop
    NUM_THREADS.times { @q.push(STOP) }
    @threads.map(&:join)
  end

  def enqueue(job, websocket)
    @q.push(job, websocket)
  end

  def do_work(job, websocket)
    # .....
    notify_complete(websocket)
  end

  def notify_complete(websocket)
  end
end

$wp = WorkerPool.new
$wp.start
at_exit { $wp.stop }

# in your controller
wp.enqueue(job, websocket)