Skip to content

Add terminate_workers to ProcessPoolExecutor #128041

Closed
Closed
Add terminate_workers to ProcessPoolExecutor#128041
Labels
stdlibStandard Library Python modules in the Lib/ directorytopic-multiprocessingtype-featureA feature request or enhancement

Description

@csm10495
csm10495
opened on Dec 17, 2024

Feature or enhancement

Proposal:

This is an interpretation of the feature ask in: https://discuss.python.org/t/cancel-running-work-in-processpoolexecutor/58605/1. It would be a way to stop all the workers running in a ProcessPoolExecutor

p = ProcessPoolExecutor()
# use p

# i know i want p to die at this point no matter what
p.terminate_workers()

Previously the way to do this was to use to loop through the ._processes of the ProcessPoolExecutor though, preferably this should be possible without accessing implementation details.

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/cancel-running-work-in-processpoolexecutor/58605/1

Linked PRs

Activity

  1. csm10495
    added
    type-featureA feature request or enhancement
    on Dec 17, 2024
  2. picnixz
    added
    stdlibStandard Library Python modules in the Lib/ directory
    on Dec 17, 2024
  3. csm10495
    added a commit that references this issue on Dec 17, 2024

    pythongh-128041 - Add a terminate_workers method to ProcessPoolExecutor

    47b162a
  4. gpshead
    added a commit that references this issue on Mar 3, 2025

    gh-128041: Add `terminate_workers` and `kill_workers` methods to Proc…

    f97e409
  5. gpshead
    added
    3.14bugs and security fixes
    on Mar 3, 2025

  6. gpshead commented on Mar 3, 2025

    @gpshead
    gpshead
    on Mar 3, 2025
    Member

    thanks for the feature contribution!

  7. gpshead
    closed this as completedon Mar 3, 2025

  8. picnixz commented on Mar 3, 2025

    @picnixz
    picnixz
    on Mar 3, 2025
    Member

    Re-opening because we have some build bots failing (I'm not sure whether the macOS failure is related but the other seems so)

    https://github.com/python/cpython/actions/runs/13631446353/job/38099943353#step:11:686
    https://buildbot.python.org/#/builders/568/builds/8398

  9. picnixz
    reopened this on Mar 3, 2025

  10. csm10495 commented on Mar 3, 2025

    @csm10495
    csm10495
    on Mar 3, 2025
    ContributorAuthor

    Opened #130812 to try to fix the transiency. I can't seem to add the skip-news label, but it should get that.

  11. colesbury
    added 2 commits that reference this issue on Mar 4, 2025

    Revert "pythongh-128041: Add `terminate_workers` and `kill_workers` m…

    cc0921f

    Revert "gh-128041: Add `terminate_workers` and `kill_workers` methods…

    efadc58

  12. colesbury commented on Mar 4, 2025

    @colesbury
    colesbury
    on Mar 4, 2025
    Contributor

    @csm10495 - I reverted #128043 due to CI failures. Please open a new PR with the changes and fixes when you have a chance. I can help with testing if you'd like.

  13. csm10495 commented on Mar 4, 2025

    @csm10495
    csm10495
    on Mar 4, 2025
    ContributorAuthor

    Thanks! @colesbury. I'll dig more to figure out the issue before opening a fresh pr.

  14. picnixz
    removed
    3.14bugs and security fixes
    on Mar 4, 2025

  15. csm10495 commented on Mar 4, 2025

    @csm10495
    csm10495
    on Mar 4, 2025
    ContributorAuthor

    Current issue:

    test_force_shutdown_workers_stops_pool (test.test_concurrent_futures.test_process_pool.ProcessPoolForkserverProcessPoolExecutorTest.test_force_shutdown_workers_stops_pool) ... 0.07s Warning -- reap_children() reaped child process 33328
...

0:00:09 load avg: 2.32 [1/1/1] test.test_concurrent_futures.test_process_pool failed (env changed)

== Tests result: ENV CHANGED ==

1 test altered the execution environment (env changed):
    test.test_concurrent_futures.test_process_pool

Total duration: 9.0 sec
Total tests: run=84 skipped=9
Total test files: run=1/1 env_changed=1
Result: ENV CHANGED

    Interestingly enough it was suggested that commenting out

                self.assertRaises(RuntimeError, executor.submit, time.sleep, 0)

    makes the test pass. It does.. most of the time. It still transiently fails the same way with a leaked child process (though much rarer).

    So I guess the timing changed caused by that line make it more likely to happen, but we're still dealing with a race condition.

  16. csm10495 commented on Mar 4, 2025

    @csm10495
    csm10495
    on Mar 4, 2025
    ContributorAuthor

    I think I figured it out. Will open a PR in a few minutes.

  17. csm10495
    added a commit that references this issue on Mar 4, 2025

    pythongh-128041: Add `terminate_workers` and `kill_workers` methods t…

    ec7599c

  18. csm10495 commented on Mar 4, 2025

    @csm10495
    csm10495
    on Mar 4, 2025
    ContributorAuthor

    Opened a new PR: #130849. I believe the transient issues are resolved.

  19. gpshead commented on Mar 4, 2025

    @gpshead
    gpshead
    on Mar 4, 2025
    Member

    FWIW on the original PR while I suspected we might have flakiness issues... I was way underestimating that apparently. I should've does the buildbot tests before merging. sorry for the churn! :)

  20. picnixz
    added
    topic-multiprocessing
    on Mar 4, 2025
  21. gpshead
    added a commit that references this issue on Mar 5, 2025

    gh-128041: Add `terminate_workers` and `kill_workers` methods to Proc…

    ba05a4e

  22. gpshead commented on Mar 5, 2025

    @gpshead
    gpshead
    on Mar 5, 2025
    Member

    merged again with the improvements. 🤞🏾

  23. gpshead
    closed this as completedon Mar 5, 2025

  24. csm10495 commented on Mar 5, 2025

    @csm10495
    csm10495
    on Mar 5, 2025
    ContributorAuthor

    Tiny related fix: #130900 (docs only)

  25. colesbury
    added a commit that references this issue on Mar 5, 2025

    gh-128041: Fix incorrect bullet placement in "What's new" (GH-130900)

    5e73ece
  26. duaneg
    added 2 commits that reference this issue on Mar 19, 2025

    pythongh-130895: fix multiprocessing.Process join/wait/poll races

    c79293d

    pythongh-130895: fix multiprocessing.Process join/wait/poll races

    a1408a4
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    stdlibStandard Library Python modules in the Lib/ directorytopic-multiprocessingtype-featureA feature request or enhancement

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions