一个Python多进程错误

Question

我这里有一个多进程的示例，但遇到了一些问题。研究了一晚上，我还是没能找到原因。有没有人能帮我一下？

我想要一个父进程充当生产者，当有任务到来时，父进程可以派生一些子进程来处理这些任务。父进程会监控这些子进程，如果有哪个子进程异常退出，父进程可以重新启动它。


#!/usr/bin/env python
# -*- coding: utf-8 -*-

from multiprocessing import Process, Queue from Queue import Empty import sys, signal, os, random, time import traceback

child_process = []
child_process_num = 4
queue = Queue(0)

def work(queue):
    signal.signal(signal.SIGINT, signal.SIG_DFL)
    signal.signal(signal.SIGTERM, signal.SIG_DFL)
    signal.signal(signal.SIGCHLD, signal.SIG_DFL)

    time.sleep(10) #demo sleep 

def kill_child_processes(signum, frame):
    #terminate all children
    pass

def restart_child_process(signum, frame):
    global child_process

    for i in xrange(len(child_process)):
        child = child_process[i]

        try:
            if child.is_alive():
                continue
        except OSError, e:
            pass

        child.join() #join this process to make sure there is no zombie process

        new_child = Process(target=work, args=(queue,))
        new_child.start()
        child_process[i] = new_child #restart one new process

        child = None
        return

if __name__ == '__main__':
    reload(sys)
    sys.setdefaultencoding("utf-8")

    for i in xrange(child_process_num):
        child = Process(target=work, args=(queue,))
        child.start()
        child_process.append(child)

    signal.signal(signal.SIGINT, kill_child_processes)
    signal.signal(signal.SIGTERM, kill_child_processes) #hook the SIGTERM
    signal.signal(signal.SIGCHLD, restart_child_process)
    signal.signal(signal.SIGPIPE, signal.SIG_DFL)

当这个程序运行时，会出现如下错误：

Error in atexit._run_exitfuncs:
Error in sys.exitfunc:
Traceback (most recent call last):
  File "/usr/local/python/lib/python2.6/atexit.py", line 30, in _run_exitfuncs
    traceback.print_exc()
  File "/usr/local/python/lib/python2.6/traceback.py", line 227, in print_exc
    print_exception(etype, value, tb, limit, file)
  File "/usr/local/python/lib/python2.6/traceback.py", line 124, in print_exception
    _print(file, 'Traceback (most recent call last):')
  File "/usr/local/python/lib/python2.6/traceback.py", line 12, in _print
    def _print(file, str='', terminator='\n'):
  File "test.py", line 42, in restart_child_process
    new_child.start()
  File "/usr/local/python/lib/python2.6/multiprocessing/process.py", line 99, in start
    _cleanup()
  File "/usr/local/python/lib/python2.6/multiprocessing/process.py", line 53, in _cleanup
    if p._popen.poll() is not None:
  File "/usr/local/python/lib/python2.6/multiprocessing/forking.py", line 106, in poll
    pid, sts = os.waitpid(self.pid, flag)
OSError: [Errno 10] No child processes

如果我给某个子进程发送信号：kill –SIGINT {child_pid}，我会得到：

[root@mail1 mail]# kill -SIGINT 32545
[root@mail1 mail]# Error in atexit._run_exitfuncs:
Traceback (most recent call last):
  File "/usr/local/python/lib/python2.6/atexit.py", line 24, in _run_exitfuncs
    func(*targs, **kargs)
  File "/usr/local/python/lib/python2.6/multiprocessing/util.py", line 269, in _exit_function
    p.join()
  File "/usr/local/python/lib/python2.6/multiprocessing/process.py", line 119, in join
    res = self._popen.wait(timeout)
  File "/usr/local/python/lib/python2.6/multiprocessing/forking.py", line 117, in wait
    return self.poll(0)
  File "/usr/local/python/lib/python2.6/multiprocessing/forking.py", line 106, in poll
    pid, sts = os.waitpid(self.pid, flag)
OSError: [Errno 4] Interrupted system call Error in sys.exitfunc:
Traceback (most recent call last):
  File "/usr/local/python/lib/python2.6/atexit.py", line 24, in _run_exitfuncs
    func(*targs, **kargs)
  File "/usr/local/python/lib/python2.6/multiprocessing/util.py", line 269, in _exit_function
    p.join()
  File "/usr/local/python/lib/python2.6/multiprocessing/process.py", line 119, in join
    res = self._popen.wait(timeout)
  File "/usr/local/python/lib/python2.6/multiprocessing/forking.py", line 117, in wait
    return self.poll(0)
  File "/usr/local/python/lib/python2.6/multiprocessing/forking.py", line 106, in poll
    pid, sts = os.waitpid(self.pid, flag)
OSError: [Errno 4] Interrupted system call

异常处理进程管理信号处理子进程多进程任务调度生产者消费者模型

一个Python多进程错误

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