python: run a process with timeout and capture stdout, stderr and exit status

Question

Possible Duplicate:
subprocess with timeout

What is the easiest way to do the following in Python:

Run an external process
Capture stdout in a string, stderr, and exit status
Set a timeout.

I would like something like this:

import proc

try:
    status, stdout, stderr = proc.run(["ls", "-l"], timeout=10)
except proc.Timeout:
    print "failed"

Just so we know where you're starting from, have you considered the `subprocess` module? http://docs.python.org/library/subprocess.html — Greg Hewgill, Oct 12 '09 at 19:11
subprocess' Popen.communicate with timeout, similar question: http://stackoverflow.com/questions/1191374/subprocess-with-timeout — Mark, Oct 12 '09 at 19:15

flybywire · Accepted Answer · 2009-10-12T22:40:22.007

13

I hate doing the work by myself. Just copy this into your proc.py module.

import subprocess
import time
import sys

class Timeout(Exception):
    pass

def run(command, timeout=10):
    proc = subprocess.Popen(command, bufsize=0, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    poll_seconds = .250
    deadline = time.time()+timeout
    while time.time() < deadline and proc.poll() == None:
        time.sleep(poll_seconds)

    if proc.poll() == None:
        if float(sys.version[:3]) >= 2.6:
            proc.terminate()
        raise Timeout()

    stdout, stderr = proc.communicate()
    return stdout, stderr, proc.returncode

if __name__=="__main__":
    print run(["ls", "-l"])
    print run(["find", "/"], timeout=3) #should timeout

edited Oct 12 '09 at 22:40

answered Oct 12 '09 at 19:52

flybywire

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This version might timeout due to pipe buffer overflow (when stdout or stderr ~64K). – jfs Oct 12 '09 at 22:19
1

If the command times out, you won't get any output generated up to the timeout. – Mike Mazur Oct 13 '09 at 01:57
print run(["ping www.redicecn.com"], timeout=10),the script threw out Timeout exception, but the ping process was still running. – redice Sep 06 '12 at 12:33

score 12 · Answer 2 · answered Oct 12 '09 at 23:33

12

Note on linux with coreutils >= 7.0 you can prepend timeout to the command like:

timeout 1 sleep 1000

answered Oct 12 '09 at 23:33

pixelbeat

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python: run a process with timeout and capture stdout, stderr and exit status

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