Class: ParallelWork::Runner

Inherits:
Object
  • Object
show all
Defined in:
lib/parallel_work/runner.rb

Constant Summary collapse

SOCKET_MAX_LEN = 
1000
MESSAGE_LEN = 
5

Instance Method Summary collapse

Constructor Details

#initialize(work, process_block) ⇒ Runner

Returns a new instance of Runner.

Parameters:

  • work (#next) 


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# File 'lib/parallel_work/runner.rb', line 8

def initialize work, process_block
  @work = work
  @process_block = process_block
  @master = nil
  @parent_sockets = []
end

Instance Method Details

#close_other_sockets ⇒ Object 



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# File 'lib/parallel_work/runner.rb', line 38

def close_other_sockets
  if @master
    @child_socket.close
  else
    @parent_sockets.each do |socket|
      socket.close
    end
  end
  self
end

#setup_sockets ⇒ Object 



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# File 'lib/parallel_work/runner.rb', line 15

def setup_sockets
  @child_socket, parent_socket = Socket.pair("AF_UNIX", "SOCK_DGRAM", 0)
  @parent_sockets << parent_socket
end

#spawn(n_workers) ⇒ Object 



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# File 'lib/parallel_work/runner.rb', line 20

def spawn n_workers
  setup_sockets

  child_pid = fork
  if child_pid
    if n_workers == 1
      @master = true
    else
      @master = false
      spawn n_workers - 1
    end
  else
    @master = false
  end

  self
end

#start ⇒ Object 



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# File 'lib/parallel_work/runner.rb', line 49

def start
  if @master
    puts "master pid #{Process.pid}"
    its_over = false
    while !@parent_sockets.empty? && (ready = IO.select(@parent_sockets))
      socket = ready[0][0]
      message_from_worker = Messaging.recv socket
      send_quit = lambda do |socket|
        Messaging.send socket, Message::Quit.new
        socket.close
      end
      begin
        if its_over
          send_quit[socket]
        else
          Messaging.send socket, Message::Work.new(@work.next)
        end
      rescue StopIteration
        its_over = true
        send_quit[socket]
      end
      @parent_sockets = @parent_sockets.reject{|s|s.closed?}
    end
  else
    puts "child pid #{Process.pid}"
    Messaging.send @child_socket, Message::Ready.new
    while (message = Messaging.recv @child_socket)
      case message
        when Message::Work
          @process_block.call(message.payload)
          Messaging.send(@child_socket, Message::Ready.new)
        when Message::Quit
          exit 0
        else
          raise "unknown message #{message}"
      end
    end
  end
end