Question

I have a thread which calls Popen to get a string back from a command line utility. This command line function does not return until some very, very laggy network data arrives. Sometimes it could take minutes, other times under a second.

If the user wants, they can can cancel waiting for this data. In this case, what is the right way to stop the thread?

class CommThread( threading.Thread ):

    def __init__(self):
        self.stdout = None
        self.stderr = None
        self.command = None
        threading.Thread.__init__(self)

    def run(self):
        if self.command is not None:
            p = Popen( self.command.split(), shell=False, stdout=PIPE, stderr=PIPE)
            self.stdout, self.stderr = p.communicate()

Answer 1

Use Popen.terminate() here’s the document http://docs.python.org/library/subprocess.html

you code should be like this:

def run(self):
    if self.command is not None:
        self.process = Popen( self.command.split(), shell=False, stdout=PIPE, stderr=PIPE)

def stop(self):
    if self.process is not None:
        self.process.terminate()

you can call CommThread.stop() in other code blocks