【问题描述】

       今天在使用Python多进程管道（multiprocessing.Pipe）的时候报了如下的错误：

Traceback (most recent call last):
  File "script/train_taobao.py", line 302, in <module>
    train(model_type=Model_Type, Memory_Size=Memory_Size, Mem_Induction=Mem_Induction, Util_Reg=Util_Reg)
  File "script/train_taobao.py", line 194, in train
    if _stop.is_set() and train_data_pool.empty():
  File "D:\anaconda\lib\multiprocessing\queues.py", line 120, in empty
    return not self._poll()
  File "D:\anaconda\lib\multiprocessing\connection.py", line 255, in poll
    self._check_closed()
  File "D:\anaconda\lib\multiprocessing\connection.py", line 136, in _check_closed
    raise OSError("handle is closed")
OSError: handle is closed

(base) D:\PythonProjects\project_nlp\mimn>Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "D:\anaconda\lib\multiprocessing\spawn.py", line 105, in spawn_main
    exitcode = _main(fd)
  File "D:\anaconda\lib\multiprocessing\spawn.py", line 115, in _main
    self = reduction.pickle.load(from_parent)
EOFError: Ran out of input

【相关原因分析】

       下面来说一下Python多进程管道的几种常见报错。

       1、如果管道发送端关闭了，接收端依然还去接收的话，接收端会在接收完管道中残存的数据之后，报如下错误：

raise EOFError

       2、如果管道中没有数据了，接收端还去接收的话，程序会卡死不动。

       3、如果管道发送端关闭了，发送端依然还去发送的话，就会报如下的错误：

OSError: handle is closed

       也就是咱们上文中报的错。

       4、如果接收端关闭了，发送端依然发送的话，会报如下的错误：

BrokenPipeError: [WinError 232] 管道正在被关闭。