Using process poll() while using gevent

[Bobby R.]

Hello,

I am using a module that requires gevent but as a consequence my existing code that uses subprocess poll() method no longer works. I understand that it is set to False because of gevent.

In short I'm running a subprocess (external command) within a thread that uses process.poll() to check for the existence of that process. Unfortunately it spits out this but still works.

  File "./app.py", line 67, in target

    self.output, self.error = self.process.communicate()

  File "/usr/lib/python2.7/subprocess.py", line 799, in communicate

    return self._communicate(input)

  File "/usr/lib/python2.7/subprocess.py", line 1401, in _communicate

    stdout, stderr = self._communicate_with_poll(input)

  File "/usr/lib/python2.7/subprocess.py", line 1431, in _communicate_with_poll

    poller = select.poll()

AttributeError: 'module' object has no attribute 'poll'

I am unclear on monkey patching and what it does in general but if I add the code below:

from gevent import monkey; monkey.patch_all(subprocess=True)

I no longer see the aforementioned error but poll() no longer works. Is there a way to use both gevent and subprocess poll() within my code?

Or is there another method to poll for whether my subprocess is still running with my thread?

Thanks

[Jason Madden]

You may find the discussion in issue 446 to be relevant (and in particular this comment summarizes the fixes). In short, in a fully and properly monkey-patched system, subprocess.Popen.poll works as expected; the trick is just to monkey patch in the correct order at the correct time.

You may also try upgrading to gevent 1.1b1 which fixes the problem in a different way; see the changelog for details.