Python subprocess timeout?

Question

Hello is there any argument or options to setup kinda subprocess.Popen(['..'], ..., timeout=20)?

Sultan

Answer 1

subprocess.Popen doesn't block so you can do something like this:

p = subprocess.Popen(['...'])
time.sleep(20)
if p.poll() is None:
  p.kill()
  print 'timed out'
else:
  print p.communicate()

Answer 2

Unfortunately, there isn't such a solution. I managed to do this using a threaded timer that would launch along with the process that would kill it after the timeout but I did run into some stale file descriptor issues because of zombie processes or some such.

Answer 3

No there is no time out. I guess, what you are looking for is to kill the sub process after some time. Since you are able to signal the subprocess, you should be able to kill it too.

generic approach to sending a signal to subprocess:

proc = subprocess.Popen([command])
time.sleep(1)
print 'signaling child'
sys.stdout.flush()
os.kill(proc.pid, signal.SIGUSR1)

You could use this mechanism to terminate after a time out period.

Answer 4

You could do

from twisted.internet import reactor, protocol, error, defer

class DyingProcessProtocol(protocol.ProcessProtocol):
    def __init__(self, timeout):
        self.timeout = timeout

    def connectionMade(self):
        @defer.inlineCallbacks
        def killIfAlive():
            try:
                yield self.transport.signalProcess('KILL')
            except error.ProcessExitedAlready:
                pass

        d = reactor.callLater(self.timeout, killIfAlive)

reactor.spawnProcess(DyingProcessProtocol(20), ...)

using Twisted's asynchronous process API.