Thread pool, and separate mongo client with each thread.

thread_pool.rb

class ThreadPool
    attr_accessor :size, :pool

    def logger
      BeatDeckMachine::logger
    end

    def initialize(size)
      @size = size
      @jobs = Queue.new
      @pool = create_pool
    end

    def create_pool
      @size.times.map do |i|
        Thread.start do
          Thread.current[:id] = i

          catch(:thread_quit) do
            session = create_mongo_client

            loop do
              job, args = @jobs.pop
              args << session
              logger.debug "Thread(#{Thread.current[:id]}): Handling job"
              job.call *args
            end
          end
        end
      end
    end

    def join
      #@pool.map(&:join)
      # This cause Deadlock ? exceptino from rb_check_deadlock
      # To avoid this situation i've used another thread to check whether all threads from pool are dead already?
      # Example - 
      # Thread.new do
      #    break until pool.pool.select(&:alive?).size.zero?
      #  end.join
    end

    def shutdown
      logger.info 'Shutting down threads.'
      @size.times do
        add { throw :thread_quit }
      end

      @pool.map &:join
    end

    def add(*args, &job)
      logger.debug 'Added new job in queue'
      @jobs << [job, args]
    end

    def queue_size;
      @jobs.size
    end

    def create_mongo_client
      # Some stuffs here with Moped::Session.new
    end
  end