Class BackgroundTask

cherrypy/process/plugins.py:485–524

A subclass of threading.Thread whose run() method repeats. Use this class for most repeating tasks. It uses time.sleep() to wait for each interval, which isn't very responsive; that is, even if you call self.cancel(), you'll have to wait until the sleep() call finishes before the th

class BackgroundTask(threading.Thread):
    """A subclass of threading.Thread whose run() method repeats.

    Use this class for most repeating tasks. It uses time.sleep() to
    wait for each interval, which isn't very responsive; that is, even
    if you call self.cancel(), you'll have to wait until the sleep()
    call finishes before the thread stops. To compensate, it defaults to
    being daemonic, which means it won't delay stopping the whole
    process.
    """

    def __init__(self, interval, function, args=[], kwargs={}, bus=None):
        super(BackgroundTask, self).__init__()
        self.interval = interval
        self.function = function
        self.args = args
        self.kwargs = kwargs
        self.running = False
        self.bus = bus

        # default to daemonic
        self.daemon = True

    def cancel(self):
        self.running = False

    def run(self):
        self.running = True
        while self.running:
            time.sleep(self.interval)
            if not self.running:
                return
            try:
                self.function(*self.args, **self.kwargs)
            except Exception:
                if self.bus:
                    self.bus.log('Error in background task thread function %r.'
                                 % self.function, level=40, traceback=True)
                # Quit on first error to avoid massive logs.
                raise


class Monitor(SimplePlugin):