Question

我试图将它作为多处理过程运行，但是当启动线程时，pickler会崩溃，我无法解决阻止它进行酸洗的问题。我已经尝试评论套接字代码和消息obj代码，但仍然无法正常工作 - 我做错了什么？

class TransmitThread(Process):

    def __init__(self, send_queue, reply_queue, control_pipe, recv_timeout=2, buffer_size=4096):
        """
            This init function is called when the thread is created. Function simply calls the Process class init
            function, and stores the class vars.
        """
        # Call process class init
        Process.__init__(self)

        # Store class vars
        self.send_queue     = send_queue
        self.reply_queue    = reply_queue
        self.control_pipe   = control_pipe
        self._recv_timeout  = recv_timeout
        self._buffer_size   = buffer_size

    def run(self):
        """
            This is the main function that is called when the thread is started.
            The function loops forever, waiting for a send message in the queue, and processes the message to send
            and fetches the response. The thread loops forever until it's terminated or the KILL THREAD command is
            passed through the control pipe.
        """
        # Start our forever running loop
        while True:

            # Check if there is anything in the pipe
            if self.control_pipe.poll():
                # Check if we received the kill thread command
                if self.control_pipe.recv() == KILL_THREAD_COMMAND:
                    # Kill the while loop and end the thread
                    break

            # Check if there is anything in message queue
            if not self.send_queue.empty():
                # Fetch message from the queue to send, and unpickle
                message_obj, message_pickle = self.send_queue.get()

                # Open socket and set timeout
                sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
                sock.settimeout(self._recv_timeout)

                # Connect socket to the recipient
                sock.connect( message_obj.recipient_address )

                # Push the pickled message down the socket
                sock.sendall(message_pickle)

                # Check if the message we send is a request (should get a response)
                if str(message_obj.message_type) == str(Message.REQUEST):

                    print "fetching reply"

                    # Lets fetch the response, and push the pickled message onto the queue
                    self.reply_queue.put( sock.recv(self._buffer_size) )

                    print "got a reply"

                # All done, close the socket
                sock.close()

            # Add small delay to stop this thread consuming too much CPU time
            sleep(0.1)

错误消息是：

File "C:/Users/oliver/OneDrive/GIT/pyke/pyke.py", line 127, in __init__
    self.thread.start()
  File "C:\Python27\lib\multiprocessing\process.py", line 130, in start
    self._popen = Popen(self)
  File "C:\Python27\lib\multiprocessing\forking.py", line 277, in __init__
    dump(process_obj, to_child, HIGHEST_PROTOCOL)
  File "C:\Python27\lib\multiprocessing\forking.py", line 199, in dump
    ForkingPickler(file, protocol).dump(obj)
  File "C:\Python27\lib\pickle.py", line 224, in dump
    self.save(obj)
  File "C:\Python27\lib\pickle.py", line 331, in save
    self.save_reduce(obj=obj, *rv)
  File "C:\Python27\lib\pickle.py", line 419, in save_reduce
    save(state)
  File "C:\Python27\lib\pickle.py", line 286, in save
    f(self, obj) # Call unbound method with explicit self
  File "C:\Python27\lib\pickle.py", line 649, in save_dict
    self._batch_setitems(obj.iteritems())
  File "C:\Python27\lib\pickle.py", line 681, in _batch_setitems
    save(v)
  File "C:\Python27\lib\pickle.py", line 286, in save
    f(self, obj) # Call unbound method with explicit self
  File "C:\Python27\lib\pickle.py", line 725, in save_inst
    save(stuff)
  File "C:\Python27\lib\pickle.py", line 286, in save
    f(self, obj) # Call unbound method with explicit self
  File "C:\Python27\lib\pickle.py", line 649, in save_dict
    self._batch_setitems(obj.iteritems())
  File "C:\Python27\lib\pickle.py", line 681, in _batch_setitems
    save(v)
  File "C:\Python27\lib\pickle.py", line 331, in save
    self.save_reduce(obj=obj, *rv)
  File "C:\Python27\lib\pickle.py", line 419, in save_reduce
    save(state)
  File "C:\Python27\lib\pickle.py", line 286, in save
    f(self, obj) # Call unbound method with explicit self
  File "C:\Python27\lib\pickle.py", line 649, in save_dict
    self._batch_setitems(obj.iteritems())
  File "C:\Python27\lib\pickle.py", line 681, in _batch_setitems
    save(v)
  File "C:\Python27\lib\pickle.py", line 331, in save
    self.save_reduce(obj=obj, *rv)
  File "C:\Python27\lib\pickle.py", line 396, in save_reduce
    save(cls)
  File "C:\Python27\lib\pickle.py", line 286, in save
    f(self, obj) # Call unbound method with explicit self
  File "C:\Python27\lib\pickle.py", line 748, in save_global
    (obj, module, name))
pickle.PicklingError: Can't pickle <type 'thread.lock'>: it's not found as thread.lock
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "C:\Python27\lib\multiprocessing\forking.py", line 381, in main
    self = load(from_parent)
  File "C:\Python27\lib\pickle.py", line 1378, in load
    return Unpickler(file).load()
  File "C:\Python27\lib\pickle.py", line 858, in load
    dispatch[key](self)
  File "C:\Python27\lib\pickle.py", line 880, in load_eof
    raise EOFError
EOFError

Answer 1

pickler错误来自multiprocessing.Process试图在内部挑选自己的子进程。我非常确定你的一个实例变量没有正确地为子进程挑选。你的问题中哪一个不清楚

    # Store class vars
    self.send_queue     = send_queue
    self.reply_queue    = reply_queue
    self.control_pipe   = control_pipe
    self._recv_timeout  = recv_timeout
    self._buffer_size   = buffer_size

[来自OP的评论后编辑]：

问题在于send_queue和reply_queue是Queue.Queue而不是multiprocessing.Queue。在分叉子工作器时，Process尝试将自身和任何实例变量序列化为子项。但是Queue.Queue是不可序列化的本地对象，因此是错误。

此问题的另一个问题是来自multiprocessing.Queue的{{1}} re-uses the exceptions而没有重新导出这些内容。这is actually documented虽然有些隐藏在杂乱的下方：

注意： Queue使用通常的multiprocessing和Queue.Empty例外来表示超时。它们在Queue.Full命名空间中不可用，因此您需要从multiprocessing导入它们。

为什么不这个泡菜？

1 个答案: