timed function

#!/usr/bin/env python
# -*- coding: utf-8 -*-
'''For running command line executables with a timeout'''

import subprocess
import threading
import shlex
import sys
import traceback


class TimedProc(object):
    '''
    Create a TimedProc object, calls subprocess.
    '''
    def __init__(self, cmd):

        self.command = cmd
        cmdargs = shlex.split(cmd)
        self.process = subprocess.Popen(cmdargs, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        self.stdout = ""
        self.stderr = ""

    def wait(self, timeout=None):
        '''
        wait for subprocess to terminate and return subprocess' return code.
        If timeout is reached, throw TimedProcTimeoutError
        '''
        def receive():
            (self.stdout, self.stderr) = self.process.communicate()

        if timeout:
            if not isinstance(timeout, (int, float)):
                raise Exception('Error: timeout must be a number')
            rt = threading.Thread(target=receive)
            rt.start()
            rt.join(timeout)
            if rt.isAlive():
                # Subprocess cleanup (best effort)
                self.process.kill()

                def terminate():
                    if rt.isAlive():
                        self.process.terminate()
                # quit after 1 seconds
                threading.Timer(1, terminate).start()
                raise Exception(
                    '%s : Timed out after %s seconds' % (
                        self.command,
                        str(timeout),
                    )
                )
        else:
            receive()
        return self.process.returncode


def run_cmd(cmd, timeout=5):
    if cmd is None:
        return (-1, '', 'command should not be empty')
    tci = TimedProc(cmd)
    try:
        ret = tci.wait(timeout)
        if ret == 0:
            return (0, tci.stdout, '')
        else:
            sys.stderr.write(tci.stderr)
            return (-1, '', tci.stderr)
    except Exception, e:
        return (-2, '', traceback.format_exc(e))


if __name__ == '__main__':
    rc, stdout, stderr = run_cmd('sleep 7')
    if rc == 0:
        print(stdout)
    else:
        print(stderr)