Class: WorkQueue

Inherits:
Object
  • Object
show all
Defined in:
lib/scout/work_queue.rb,
lib/scout/work_queue/socket.rb,
lib/scout/work_queue/worker.rb

Defined Under Namespace

Classes: Socket, Worker

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(workers = 0, &block) ⇒ WorkQueue 



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# File 'lib/scout/work_queue.rb', line 15

def initialize(workers = 0, &block)
  workers = workers.to_i if String === workers
  @input = WorkQueue::Socket.new
  @output = WorkQueue::Socket.new
  @workers = workers.times.collect{ new_worker }
  @worker_proc = block
  @worker_mutex = Mutex.new
  @removed_workers = []
  Log.medium "Starting queue #{queue_id} with workers: #{Log.fingerprint @workers.collect{|w| w.worker_short_id }} and sockets #{@input.socket_id} and #{@output.socket_id}"
end

Instance Attribute Details

#callback ⇒ Object

Returns the value of attribute callback.



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# File 'lib/scout/work_queue.rb', line 7

def callback
  @callback
end

#worker_proc ⇒ Object

Returns the value of attribute worker_proc.



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# File 'lib/scout/work_queue.rb', line 7

def worker_proc
  @worker_proc
end

#workers ⇒ Object

Returns the value of attribute workers.



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# File 'lib/scout/work_queue.rb', line 7

def workers
  @workers
end

Instance Method Details

#abort ⇒ Object 



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# File 'lib/scout/work_queue.rb', line 154

def abort
  @aborted = true
  Log.low "Aborting #{@workers.length} workers in queue #{queue_id}"
  @worker_mutex.synchronize do
    @workers.each do |w| 
      ScoutSemaphore.post_semaphore(@output.write_sem)
      ScoutSemaphore.post_semaphore(@input.read_sem)
      w.abort 
    end
  end
end

#add_worker(&block) ⇒ Object 



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# File 'lib/scout/work_queue.rb', line 30

def add_worker(&block)
  worker = new_worker
  @worker_mutex.synchronize do
    @workers.push(worker)
    if block_given?
      worker.process @input, @output, &block
    else
      worker.process @input, @output, &@worker_proc
    end
  end
  worker
end

#clean ⇒ Object 



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# File 'lib/scout/work_queue.rb', line 177

def clean
  @waiter.join if @waiter && Thread.current != @waiter
  @input.clean
  @output.clean
end

#close ⇒ Object 



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# File 'lib/scout/work_queue.rb', line 166

def close
  return if @closed || @aborted
  @closed = true
  @worker_mutex.synchronize{ @workers.length }.times do
    begin
      @input.write DoneProcessing.new() unless @input.closed_write?
    rescue IOError,Errno::ENOENT
    end
  end
end

#ignore_ouput ⇒ Object 



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# File 'lib/scout/work_queue.rb', line 43

def ignore_ouput
  @workers.each{|w| w.ignore_ouput = true }
end

#join(clean = true) ⇒ Object 



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# File 'lib/scout/work_queue.rb', line 183

def join(clean = true)
  close
  begin
    @waiter.join if @waiter
    @reader.join if @reader
  ensure
    self.clean if clean
  end
end

#new_worker ⇒ Object 



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# File 'lib/scout/work_queue.rb', line 9

def new_worker
  worker = Worker.new
  worker.queue_id = queue_id
  worker
end

#process(&callback) ⇒ Object 



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# File 'lib/scout/work_queue.rb', line 64

def process(&callback)
  @workers.each do |w| 
    w.process @input, @output, &@worker_proc
  end

  @reader = Thread.new(Thread.current) do |parent|
    begin
      Thread.current.report_on_exception = false
      Thread.current["name"] = "Output reader #{queue_id}"
      @done_workers ||= []
      while true
        obj = @output.read
        if DoneProcessing === obj

          done = @worker_mutex.synchronize do
            Log.low "Worker #{obj.pid} from #{queue_id} done"
            @done_workers << obj.pid
            #@closed && (@workers.empty? || @workers.length == @removed_workers.length + @done_workers.length)
            @closed && @done_workers.length == @removed_workers.length + @workers.length
          end

          break if done
        elsif Exception === obj
          raise obj
        else
          callback.call obj if callback
        end
      end
      @waiter.join if @workers.any?
    rescue DoneProcessing
    rescue Aborted
    rescue WorkerException
      Log.error "Exception in worker #{obj.pid} in queue #{queue_id}: #{obj.worker_exception.message}"
      self.abort
      @input.abort obj.worker_exception
      raise obj.worker_exception
    rescue
      Log.error "Exception processing output in queue #{queue_id}: #{$!.message}"
      self.abort
      raise $!
    end
  end

  Thread.pass until @reader["name"]

  Thread.pass until @worker_mutex.synchronize{ @workers.select{|w| w.pid.nil? }.empty? }

  @waiter = Thread.new do
    Thread.current.report_on_exception = false
    Thread.current["name"] = "Worker waiter #{queue_id}"
    while true
      break if @worker_mutex.synchronize{ @workers.empty? }
      threads = @workers.collect do |w|
        t = Thread.new do
          Thread.current.report_on_exception = false
          Thread.current["name"] = "Worker waiter #{queue_id} worker #{w.pid}"
          pid, status = Process.wait2 w.pid
          remove_worker(pid) if pid
          #@output.write WorkerException.new(Exception.new("Worker ended with status #{status.exitstatus}"), pid) unless status.success?
          raise Exception.new("Worker #{pid} ended with status #{status.exitstatus}") unless (status.success? || status.exitstatus == WorkQueue::Worker::EXIT_STATUS)
        end
        Thread.pass until t["name"]
        t
      end
      exceptions = []
      threads.each do |t| 
        begin
          t.join 
        rescue Exception
          exceptions << $!
        end
      end

      raise exceptions.first if exceptions.any?
    end
  end

  Thread.pass until @waiter["name"]
end

#queue_id ⇒ Object 



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# File 'lib/scout/work_queue.rb', line 26

def queue_id
  [object_id, Process.pid] * "@"
end

#remove_one_worker ⇒ Object 



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# File 'lib/scout/work_queue.rb', line 47

def remove_one_worker
  @input.write DoneProcessing.new
end

#remove_worker(pid) ⇒ Object 



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# File 'lib/scout/work_queue.rb', line 51

def remove_worker(pid)
  @worker_mutex.synchronize do
    worker = @workers.index{|w| w.pid == pid}
    if worker
      @workers.delete_at(worker)
      @removed_workers << pid
      Log.low "Removed worker #{pid} from #{queue_id}"
    else
      Log.medium "Worker #{pid} not from #{queue_id}"
    end
  end
end

#write(obj) ⇒ Object 



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# File 'lib/scout/work_queue.rb', line 144

def write(obj)
  begin
    @input.write obj
  rescue Exception
    raise $! unless @input.exception
  ensure
    raise @input.exception if @input.exception
  end
end