On 5 Mar, 10:33, "Dmitry Teslenko" <[EMAIL PROTECTED]> wrote: > Hello! > Here's my implementation of a function that executes some command and > drains stdout/stderr invoking other functions for every line of > command output: > > def __execute2_drain_pipe(queue, pipe): > for line in pipe: > queue.put(line) > return > > def execute2(command, out_filter = None, err_filter = None): > p = subprocess.Popen(command , shell=True, stdin = subprocess.PIPE, \ > stdout = subprocess.PIPE, stderr = subprocess.PIPE, \ > env = os.environ) > > qo = Queue.Queue() > qe = Queue.Queue() > > to = threading.Thread(target = __execute2_drain_pipe, \ > args = (qo, p.stdout)) > to.start() > time.sleep(0) > te = threading.Thread(target = __execute2_drain_pipe, \ > args = (qe, p.stderr)) > te.start() > > while to.isAlive() or te.isAlive(): > try: > line = qo.get() > if out_filter: > out_filter(line) > qo.task_done() > except Queue.Empty: > pass > > try: > line = qe.get() > if err_filter: > err_filter(line) > qe.task_done() > except Queue.Empty: > pass > > to.join() > te.join() > return p.wait() > > Problem is my implementation is buggy and function hungs when there's > empty stdout/stderr. Can I have your feedback?
The Queue.get method by default is blocking. The documentation is not 100% clear about that (maybe it should report the full python definition of the function parameters, which makes self-evident the default value) but if you do help(Queue.Queue) in a python shell you will see it. Hence, try using a timeout or a non-blocking get (but in case of a non blocking get you should add a delay in the loop, or you will poll the queues at naximum speed and maybe prevent the other threads from accessing them). Ciao ----- FB -- http://mail.python.org/mailman/listinfo/python-list
