python subprocess with timeout

gistfile1.py

  def timeout_command(command, timeout):
    """call shell-command and either return its output or kill it
    if it doesn't normally exit within timeout seconds and return None"""
    import subprocess, datetime, os, time, signal
    start = datetime.datetime.now()
    process = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    while process.poll() is None:
      time.sleep(0.1)
      now = datetime.datetime.now()
      if (now - start).seconds> timeout:
        os.kill(process.pid, signal.SIGKILL)
        os.waitpid(-1, os.WNOHANG)
        return None
    return process.stdout.read()