I did read that portion of the doc, then I change it to communicate and it still hangs. So I reverted back to "wait" while launching one thread to see if I could isolate the problem, but it still hangs regardless of using "wait" or "communicate".
-----Original Message----- From: ch...@rebertia.com [mailto:ch...@rebertia.com] On Behalf Of Chris Rebert Sent: Tuesday, August 09, 2011 11:53 PM To: Danny Wong (dannwong) Cc: python-list@python.org Subject: Re: subprocess.Popen and thread module > On Tue, Aug 9, 2011 at 11:38 PM, Danny Wong (dannwong) > <dannw...@cisco.com> wrote: >> Hi All, >> I'm trying to execute some external commands from multiple database. >> I'm using threads and subprocess.Popen ( from docs, all the popen* >> functions are deprecated and I was told to use subprocess.Popen) to >> execute the external commands in parallel, but the commands seems to >> hang. > > What's your Popen() call look like? On Tue, Aug 9, 2011 at 11:48 PM, Danny Wong (dannwong) <dannw...@cisco.com> wrote: > try: > cmd_output = subprocess.Popen(['scm', 'load', '--force', '-r', > nickname, '-d', directory, project], stdout=subprocess.PIPE, > stderr=subprocess.PIPE) > status = cmd_output.wait() Er, did you read the warning about Popen.wait() in the docs? (emphasis added): """ Popen.wait() Wait for child process to terminate. Set and return returncode attribute. Warning: ***This will deadlock*** when using stdout=PIPE and/or stderr=PIPE and the child process generates enough output to a pipe such that it blocks waiting for the OS pipe buffer to accept more data. Use communicate() to avoid that. """ – http://docs.python.org/library/subprocess.html#subprocess.Popen.wait Cheers, Chris -- http://mail.python.org/mailman/listinfo/python-list
