Pause/Resume functions for timer

I need to use a timer which can be paused and resumed. As far as I know there is only one timer in Python which is contained in the threading package, but I cannot pause or resume it, only cancel it.

This is a standard code to use the timer in Python:

from threading import Timer
import time

def timeout():
     print "Game over"

t = Timer(20 * 60, timeout)
t.start()

So what should I do to realize pause/resume functions with this timer?

import threading, time

class ResumableTimer:
    def __init__(self, timeout, callback):
        self.timeout = timeout
        self.callback = callback
        self.timer = threading.Timer(timeout, callback)
        self.startTime = time.time()

    def start(self):
        self.timer.start()

    def pause(self):
        self.timer.cancel()
        self.pauseTime = time.time()

    def resume(self):
        self.timer = threading.Timer(
            self.timeout - (self.pauseTime - self.startTime),
            self.callback)

        self.timer.start()

Your homework:

• Inheritance?
• Exceptions? Checks?
• Something better than a resumable timer

final class release

from threading import Timer
import time


class RenewableTimer:

    def __init__(self, timeout, callback):
        self.timer = Timer(timeout, callback)

        self.start_time = None
        self.cancel_time = None

        # Used for creating a new timer upon renewal
        self.timeout = timeout
        self.callback = callback

    def cancel(self):
        self.timer.cancel()

    def start(self):
        # NOTE: erroneously calling this after pausing causes errors where
        # start_time is updated, and then you get a RuntimeError
        # for trying to restart a thread
        self.start_time = time.time()
        self.timer.start()

    def pause(self):
        self.cancel_time = time.time()
        self.timer.cancel()
        return self.get_remaining_time()

    def resume(self):
        self.timeout = self.get_remaining_time()
        self.timer = Timer(self.timeout, self.callback)
        self.start_time = time.time()
        self.timer.start()

    def get_remaining_time(self):
        if self.start_time is None or self.cancel_time is None:
            return self.timeout
        return self.timeout - (self.cancel_time - self.start_time)