https://github.com/python/cpython/commit/951c7dba79a654d22d50205c181d86a207be181b commit: 951c7dba79a654d22d50205c181d86a207be181b branch: 3.13 author: Miss Islington (bot) <[email protected]> committer: Yhg1s <[email protected]> date: 2024-09-24T11:11:31-07:00 summary:
[3.13] gh-108951: Document how to terminate an asyncio.TaskGroup (GH-123837) (#123956) gh-108951: Document how to terminate an asyncio.TaskGroup (GH-123837) We don't want to add another API, since the recipe is straightforward and rarely needed. The advantage is that we could backport this to the earliest Python version that has taskgroups (3.11, alas in security mode already, so we'll just do 3.12 and 3.13). (cherry picked from commit ef05801ba0cbf090034df17e2a0420fb42c2d538) Co-authored-by: Bénédikt Tran <[email protected]> files: M Doc/library/asyncio-task.rst diff --git a/Doc/library/asyncio-task.rst b/Doc/library/asyncio-task.rst index abf1726b34f539..4716a3f9c8ac79 100644 --- a/Doc/library/asyncio-task.rst +++ b/Doc/library/asyncio-task.rst @@ -414,6 +414,53 @@ reported by :meth:`asyncio.Task.cancelling`. Improved handling of simultaneous internal and external cancellations and correct preservation of cancellation counts. +Terminating a Task Group +------------------------ + +While terminating a task group is not natively supported by the standard +library, termination can be achieved by adding an exception-raising task +to the task group and ignoring the raised exception: + +.. code-block:: python + + import asyncio + from asyncio import TaskGroup + + class TerminateTaskGroup(Exception): + """Exception raised to terminate a task group.""" + + async def force_terminate_task_group(): + """Used to force termination of a task group.""" + raise TerminateTaskGroup() + + async def job(task_id, sleep_time): + print(f'Task {task_id}: start') + await asyncio.sleep(sleep_time) + print(f'Task {task_id}: done') + + async def main(): + try: + async with TaskGroup() as group: + # spawn some tasks + group.create_task(job(1, 0.5)) + group.create_task(job(2, 1.5)) + # sleep for 1 second + await asyncio.sleep(1) + # add an exception-raising task to force the group to terminate + group.create_task(force_terminate_task_group()) + except* TerminateTaskGroup: + pass + + asyncio.run(main()) + +Expected output: + +.. code-block:: text + + Task 1: start + Task 2: start + Task 1: done + Sleeping ======== _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3/lists/python-checkins.python.org/ Member address: [email protected]
