CODEWITHSUNDEEP
pythonmultithreadingthread-sleep
Vadim Volodin
Vadim Volodin

Reputation: 407

Python threading interrupt sleep

Is there a way in python to interrupt a thread when it's sleeping? (As we can do in java)

I am looking for something like that.

  import threading
  from time import sleep

  def f():
      print('started')
  try:
      sleep(100)
      print('finished')
  except SleepInterruptedException:
      print('interrupted')

t = threading.Thread(target=f)
t.start()

if input() == 'stop':
    t.interrupt()

The thread is sleeping for 100 seconds and if I type 'stop', it interrupts

Upvotes: 18

Views: 27280

Answers (3)

Multihunter
Multihunter

Reputation: 5918

If you, for whatever reason, needed to use the time.sleep function and happened to expect the time.sleep function to throw an exception and you simply wanted to test what happened with large sleep values without having to wait for the whole timeout...

Firstly, sleeping threads are lightweight and there's no problem just letting them run in daemon mode with threading.Thread(target=f, daemon=True) (so that they exit when the program does). You can check the result of the thread without waiting for the whole execution with t.join(0.5).

But if you absolutely need to halt the execution of the function, you could use multiprocessing.Process, and call .terminate() on the spawned process. This does not give the process time to clean up (e.g. except and finally blocks aren't run), so use it with care.

Upvotes: 1

He Shiming
He Shiming

Reputation: 5819

The correct approach is to use threading.Event. For example:

import threading

e = threading.Event()
e.wait(timeout=100)   # instead of time.sleep(100)

In the other thread, you need to have access to e. You can interrupt the sleep by issuing:

e.set()

This will immediately interrupt the sleep. You can check the return value of e.wait to determine whether it's timed out or interrupted. For more information refer to the documentation: https://docs.python.org/3/library/threading.html#event-objects .

Upvotes: 37

Eirik M
Eirik M

Reputation: 816

How about using condition objects: https://docs.python.org/2/library/threading.html#condition-objects

Instead of sleep() you use wait(timeout). To "interrupt" you call notify().

Upvotes: 6

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