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在接收到SIGINT并在Python中使用代理对象后,如何防止BrokenPipeErrors?

broken-pipe sigint proxy python

Géry Ogam · 技术社区 · 7 年前

此Python程序:

import concurrent.futures
import multiprocessing
import time

class A:

    def __init__(self):
        self.event = multiprocessing.Manager().Event()

    def start(self):
        try:
            while True:
                if self.event.is_set():
                    break
                print("processing")
                time.sleep(1)
        except BaseException as e:
            print(type(e).__name__ + " (from pool thread):", e)

    def shutdown(self):
        self.event.set()

if __name__ == "__main__":
    try:
        a = A()
        pool = concurrent.futures.ThreadPoolExecutor(1)
        future = pool.submit(a.start)
        while not future.done():
            concurrent.futures.wait([future], timeout=0.1)
    except BaseException as e:
        print(type(e).__name__ + " (from main thread):", e)
    finally:
        a.shutdown()
        pool.shutdown()

输出:

processing
processing
processing
KeyboardInterrupt (from main thread):
BrokenPipeError (from pool thread): [WinError 232] The pipe is being closed
Traceback (most recent call last):
  File "C:\Program Files\Python37\lib\multiprocessing\managers.py", line 788, in _callmethod
    conn = self._tls.connection
AttributeError: 'ForkAwareLocal' object has no attribute 'connection'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File ".\foo.py", line 34, in <module>
    a.shutdown()
  File ".\foo.py", line 21, in shutdown
    self.event.set()
  File "C:\Program Files\Python37\lib\multiprocessing\managers.py", line 1067, in set
    return self._callmethod('set')
  File "C:\Program Files\Python37\lib\multiprocessing\managers.py", line 792, in _callmethod
    self._connect()
  File "C:\Program Files\Python37\lib\multiprocessing\managers.py", line 779, in _connect
    conn = self._Client(self._token.address, authkey=self._authkey)
  File "C:\Program Files\Python37\lib\multiprocessing\connection.py", line 490, in Client
    c = PipeClient(address)
  File "C:\Program Files\Python37\lib\multiprocessing\connection.py", line 691, in PipeClient
    _winapi.WaitNamedPipe(address, 1000)
FileNotFoundError: [WinError 2] The system cannot find the file specified

当它运行时 SIGINT 三秒钟后发送信号(按 Ctrl键 + C )。

分析 –The SIGINT公司 信号被发送到每个进程的主线程。在这种情况下,有两个流程:主流程和经理的子流程。

在主进程的主线程中:收到 SIGINT公司 信号,默认值 SIGINT公司 信号处理程序引发 KeyboardInterrupt 捕获并打印异常。
在管理器子进程的主线程中:同时,在收到 SIGINT公司 信号,默认值 SIGINT公司 信号处理程序引发 键盘中断 异常,终止子进程。因此,其他进程随后对管理器共享对象的所有使用都会引发 BrokenPipeError 例外
在主进程池的子线程中:在本例中 断开管道错误 在该行引发异常 if self.event.is_set(): 。
在主进程的主线程中:最后,控制流到达行 a.shutdown() ,这提高了 AttributeError 和 FileNotFoundError 例外情况。

如何防止这种情况 断开管道错误 例外

0 回复 | 直到 7 年前

Géry Ogam 7 年前

此问题的解决方案是覆盖默认值 SIGINT 具有将忽略信号的处理程序的信号处理程序,例如 signal.SIG_IGN 标准信号处理器。可以通过调用 signal.signal 经理子流程开始时的功能:

import concurrent.futures
import multiprocessing.managers
import signal
import time

def init():
    signal.signal(signal.SIGINT, signal.SIG_IGN)

class A:

    def __init__(self):
        manager = multiprocessing.managers.SyncManager()
        manager.start(init)
        self.event = manager.Event()

    def start(self):
        try:
            while True:
                if self.event.is_set():
                    break
                print("processing")
                time.sleep(1)
        except BaseException as e:
            print(type(e).__name__ + " (from pool thread):", e)

    def shutdown(self):
        self.event.set()

if __name__ == "__main__":
    try:
        a = A()
        pool = concurrent.futures.ThreadPoolExecutor(1)
        future = pool.submit(a.start)
        while not future.done():
            concurrent.futures.wait([future], timeout=0.1)
    except BaseException as e:
        print(type(e).__name__ + " (from main thread):", e)
    finally:
        a.shutdown()
        pool.shutdown()

笔记此程序还与 concurrent.futures.ProcessPoolExecutor 。