Adding Context Manger to threading.Timer

Feature or enhancement

Proposal:

Proposing to add context management to threading.Timer.

I had an issue where I didn’t want to ask the user to be patient unless they had already been waiting a while. Timer works nicely for this:

t = Timer(1, print, ("Trust me, I'm on it...",))
t.start()
time.sleep(2)
t.cancel()

Enclosing calls of start and cancel call out for context management for the obvious reasons. Sub-classing and adding it was trivial:

class Timer(Timer):
    def __enter__(self):
        self.start()

    def __exit__(self, exc_type, exc_val, exc_tb):
        self.cancel()

The first example now looks like this:

with Timer(1, print, ("Trust me, I'm on it...",)):
    time.sleep(2)

Users of the threading module will probably already be familiar with the context management features of a lock. Chaining the two together is a great way to provide feedback IF it’s needed, gotta reduce that alarm fatigue!

hold_message = Timer(10, print, ("Please hold, your call is important to us...",))

with some_lock, hold_message:
    ...

Looking to exact those changes on the core library

Has this already been discussed elsewhere?

I have already discussed this feature proposal on Discourse

Links to previous discussion of this feature:

https://discuss.python.org/t/adding-context-manger-to-threading-timer/64083

Linked PRs

• gh-125501

Start with the threading.Timer entry point and review the linked Discourse discussion and PR gh-125501. Done means Timer supports the proposed context-management usage, starting on entry and cancelling on exit, with the behavior covered as appropriate by the existing threading tests.