启动第二个进程时出现Python多处理错误

Question

Today i'm started in multiprocessing, and of course has some problems.

I create two processes:

import multiprocessing as mp

# twitter parser
twitterProc = mp.Process ( target=TwitterProcess )
twitterProc.start()

# rss parser
RssProc = mp.Process ( target=RssProcess )
RssProc.start()

When code start RssProc it work other 1-2 seconds, start fist process (twitterProc) and it work normally, then starts second process and after 1-2 seconds it stopped with such error list:

Connected to pydev debugger (build 172.3757.67)
Traceback (most recent call last):
Error in atexit._run_exitfuncs:  File "_pydevd_bundle/pydevd_cython.pyx", line 735, in _pydevd_bundle.pydevd_cython.PyDBFrame.trace_dispatch (_pydevd_bundle/pydevd_cython.c:15637)

Traceback (most recent call last):
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/atexit.py", line 24, in _run_exitfuncs
func(*targs, **kargs)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/util.py", line 325, in _exit_function
p.join()
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/process.py", line 145, in join
self.do_wait_suspend(thread, frame, event, arg)
File "_pydevd_bundle/pydevd_cython.pyx", line 252, in _pydevd_bundle.pydevd_cython.PyDBFrame.do_wait_suspend (_pydevd_bundle/pydevd_cython.c:5643)
self._args[0].do_wait_suspend(*args, **kwargs)
File "/Applications/PyCharm.app/Contents/helpers/pydev/pydevd.py", line 767, in do_wait_suspend
res = self._popen.wait(timeout)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/forking.py", line 154, in wait
return self.poll(0)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/forking.py", line 135, in poll pid, sts = os.waitpid(self.pid, flag)
KeyboardInterrupt
time.sleep(0.01)
KeyboardInterrupt
Process Process-RSS:
Traceback (most recent call last):
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/process.py", line 258, in _bootstrap
Error in sys.exitfunc:
Traceback (most recent call last):
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/atexit.py", line 24, in _run_exitfuncs
func(*targs, **kargs)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/util.py", line 325, in _exit_function
self.run()
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/process.py", line 114, in run
p.join()
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/process.py", line 145, in join
self._target(*self._args, **self._kwargs)
File "/Users/Stas/PycharmProjects/untitled/streambot.py", line 674, in __init__
res = self._popen.wait(timeout)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/forking.py", line 154, in wait
return self.poll(0)
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/multiprocessing/forking.py", line 135, in poll
pid, sts = os.waitpid(self.pid, flag)
KeyboardInterrupt
for source in config.feedList:
File "/Users/Stas/PycharmProjects/untitled/streambot.py", line 674, in __init__
for source in config.feedList:
File "_pydevd_bundle/pydevd_cython.pyx", line 970, in _pydevd_bundle.pydevd_cython.SafeCallWrapper.__call__ (_pydevd_bundle/pydevd_cython.c:19428)
ret = (<object>method_obj)(*args)
File "_pydevd_bundle/pydevd_cython.pyx", line 501, in _pydevd_bundle.pydevd_cython.PyDBFrame.trace_dispatch (_pydevd_bundle/pydevd_cython.c:18762)
cpdef trace_dispatch(self, frame, str event, arg):
File "_pydevd_bundle/pydevd_cython.pyx", line 744, in _pydevd_bundle.pydevd_cython.PyDBFrame.trace_dispatch (_pydevd_bundle/pydevd_cython.c:15791)
raise
File "_pydevd_bundle/pydevd_cython.pyx", line 735, in _pydevd_bundle.pydevd_cython.PyDBFrame.trace_dispatch (_pydevd_bundle/pydevd_cython.c:15637)
self.do_wait_suspend(thread, frame, event, arg)
File "_pydevd_bundle/pydevd_cython.pyx", line 252, in _pydevd_bundle.pydevd_cython.PyDBFrame.do_wait_suspend (_pydevd_bundle/pydevd_cython.c:5643)
self._args[0].do_wait_suspend(*args, **kwargs)
File "/Applications/PyCharm.app/Contents/helpers/pydev/pydevd.py", line 767, in do_wait_suspend
time.sleep(0.01)
KeyboardInterrupt

Process finished with exit code 0

What is that and how to solve it?

Answer 1

I think best way is to use join method after creation of the Process. join informs the main thread to wait until the process completes it's work

twitterProc.join() and RssProc.join() at the end of your script