Rename TaskFuture.abort to request_stop, execute subprocess tasks with pebble, add abort and kill by woutdenolf · Pull Request #501 · ewoks-kit/ewoksorange

woutdenolf · 2026-10-14T03:35:53Z

PR summary

Add abort (interrupts the task like Ctrl-C, with cleanup) and kill (terminates the worker process). Both work only with a process pool, which now uses pebble. They come on top of cancel and request_stop.
Calling cancel, request_stop, abort or kill on a task that is still queued prevents it from starting.
- The call returns immediately. The future completes (and raises) once a worker dequeues the task, except:
  - cancel on the thread and sync backends also cancels the future, which completes right away.
  - kill also cancels the pebble future, which completes right away.
- cancel, request_stop and abort do not cancel the pebble future: cancelling it kills the worker if one just picked up the task, which would turn them into a kill.
Process pool: replace the inter-process communication with two queues, controller→runner and runner→controller.

Try-out cancel vs. stop vs. abort vs. kill with

python scripts/ewoks_executor_demo.py --task-duration 5

Click Submit x5 (Process parallel) followed by cancel, stop, abort or kill

# Submit x5 (Process parallel) + cancel
[   4.458s] [P PARALLEL] Submitted -> 140536643910208
[   4.469s] [P PARALLEL] Submitted -> 140536643993728
[   4.481s] [P PARALLEL] Submitted -> 140536643995120
[   4.492s] [P PARALLEL] Submitted -> 140536643996608
[   4.502s] [P PARALLEL] Submitted -> 140536643998240
[   4.502s] [P PARALLEL] ▶ Started -> 140536643910208
[   4.503s] [P PARALLEL] ▶ Started -> 140536643993728
[   4.503s] [P PARALLEL] ▶ Started -> 140536643995120
[   4.503s] [P PARALLEL] ▶ Started -> 140536643996608
[   5.680s] Cancel (queued only): accepted by 1/5 tasks
[   9.486s] [P PARALLEL] ✅ 140536643910208 -> {'result': 2}
[   9.536s] [P PARALLEL] ■ Finished -> 140536643910208
[   9.539s] [P PARALLEL] ✅ 140536643993728 -> {'result': 4}
[   9.540s] [P PARALLEL] ■ Finished -> 140536643993728
[   9.541s] [P PARALLEL] ✅ 140536643995120 -> {'result': 6}
[   9.541s] [P PARALLEL] ■ Finished -> 140536643995120
[   9.543s] [P PARALLEL] ✅ 140536643996608 -> {'result': 8}
[   9.544s] [P PARALLEL] ■ Finished -> 140536643996608
[   9.544s] [P PARALLEL] 🚫 Cancelled -> 140536643998240
[   9.646s] [P PARALLEL] ■ Finished -> 140536643998240

# Submit x5 (Process parallel) + stop
[  12.566s] [P PARALLEL] Submitted -> 140536643997520
[  12.580s] [P PARALLEL] Submitted -> 140536644000592
[  12.597s] [P PARALLEL] Submitted -> 140536644002080
[  12.611s] [P PARALLEL] Submitted -> 140536644003568
[  12.622s] [P PARALLEL] Submitted -> 140536644005008
[  12.623s] [P PARALLEL] ▶ Started -> 140536643997520
[  12.625s] [P PARALLEL] ▶ Started -> 140536644000592
[  12.626s] [P PARALLEL] ▶ Started -> 140536644002080
[  12.626s] [P PARALLEL] ▶ Started -> 140536644003568
[  14.051s] Request stop: accepted by 5/5 tasks
[  14.078s] [P PARALLEL] ⏹ Stop requested -> 140536644002080
[  14.105s] [P PARALLEL] ❌ 140536644002080 -> Execution failed for ewoks task (id: None, task: '__main__.SumTask'): Stopped on request
[  14.106s] [P PARALLEL] ■ Finished -> 140536644002080
[  14.108s] [P PARALLEL] ⏹ Stop requested -> 140536644003568
[  14.109s] [P PARALLEL] ❌ 140536644003568 -> Execution failed for ewoks task (id: None, task: '__main__.SumTask'): Stopped on request
[  14.109s] [P PARALLEL] ■ Finished -> 140536644003568
[  14.110s] [P PARALLEL] ⏹ Stop requested -> 140536643997520
[  14.110s] [P PARALLEL] ❌ 140536643997520 -> Execution failed for ewoks task (id: None, task: '__main__.SumTask'): Stopped on request
[  14.110s] [P PARALLEL] ■ Finished -> 140536643997520
[  14.111s] [P PARALLEL] ⏹ Stop requested -> 140536644005008
[  14.111s] [P PARALLEL] ❌ 140536644005008 -> Task SumTask was stopped before it started
[  14.111s] [P PARALLEL] ■ Finished -> 140536644005008
[  14.114s] [P PARALLEL] ⏹ Stop requested -> 140536644000592
[  14.114s] [P PARALLEL] ❌ 140536644000592 -> Execution failed for ewoks task (id: None, task: '__main__.SumTask'): Stopped on request
[  14.114s] [P PARALLEL] ■ Finished -> 140536644000592

# Submit x5 (Process parallel) + abort
[  18.367s] [P PARALLEL] Submitted -> 140536644177840
[  18.379s] [P PARALLEL] Submitted -> 140536644179616
[  18.401s] [P PARALLEL] Submitted -> 140536644181152
[  18.411s] [P PARALLEL] Submitted -> 140536644182736
[  18.423s] [P PARALLEL] Submitted -> 140536644184320
[  18.424s] [P PARALLEL] ▶ Started -> 140536644177840
[  18.425s] [P PARALLEL] ▶ Started -> 140536644179616
[  18.425s] [P PARALLEL] ▶ Started -> 140536644181152
[  18.425s] [P PARALLEL] ▶ Started -> 140536644182736
[  20.026s] Abort (process only): accepted by 5/5 tasks
[  20.030s] [P PARALLEL] ⛔ Aborted -> 140536644179616
[  20.031s] [P PARALLEL] ❌ 140536644179616 -> Task SumTask was aborted
[  20.032s] [P PARALLEL] ■ Finished -> 140536644179616
[  20.041s] [P PARALLEL] ⛔ Aborted -> 140536644182736
[  20.042s] [P PARALLEL] ❌ 140536644182736 -> Task SumTask was aborted
[  20.044s] [P PARALLEL] ■ Finished -> 140536644182736
[  20.045s] [P PARALLEL] ⛔ Aborted -> 140536644177840
[  20.045s] [P PARALLEL] ❌ 140536644177840 -> Task SumTask was aborted
[  20.049s] [P PARALLEL] ■ Finished -> 140536644177840
[  20.052s] [P PARALLEL] ⛔ Aborted -> 140536644181152
[  20.052s] [P PARALLEL] ❌ 140536644181152 -> Task SumTask was aborted
[  20.053s] [P PARALLEL] ■ Finished -> 140536644181152
[  20.054s] [P PARALLEL] ⛔ Aborted -> 140536644184320
[  20.054s] [P PARALLEL] ❌ 140536644184320 -> Task SumTask was aborted before it started
[  20.055s] [P PARALLEL] ■ Finished -> 140536644184320

# Submit x5 (Process parallel) + kill
[  23.359s] [P PARALLEL] Submitted -> 140536644181488
[  23.377s] [P PARALLEL] Submitted -> 140536644185376
[  23.390s] [P PARALLEL] Submitted -> 140536644006208
[  23.413s] [P PARALLEL] Submitted -> 140536644183696
[  23.425s] [P PARALLEL] Submitted -> 140536644181056
[  23.426s] [P PARALLEL] ▶ Started -> 140536644181488
[  23.427s] [P PARALLEL] ▶ Started -> 140536644185376
[  23.427s] [P PARALLEL] ▶ Started -> 140536644006208
[  23.429s] [P PARALLEL] ▶ Started -> 140536644183696
[  25.652s] Kill (process only): accepted by 5/5 tasks
[  25.653s] [P PARALLEL] 💀 Killed -> 140536644181488
[  25.654s] [P PARALLEL] ❌ 140536644181488 -> The task was killed
[  25.654s] [P PARALLEL] ■ Finished -> 140536644181488
[  25.655s] [P PARALLEL] 💀 Killed -> 140536644185376
[  25.655s] [P PARALLEL] ❌ 140536644185376 -> The task was killed
[  25.656s] [P PARALLEL] ■ Finished -> 140536644185376
[  25.656s] [P PARALLEL] 💀 Killed -> 140536644006208
[  25.657s] [P PARALLEL] ❌ 140536644006208 -> The task was killed
[  25.657s] [P PARALLEL] ■ Finished -> 140536644006208
[  25.658s] [P PARALLEL] 💀 Killed -> 140536644183696
[  25.658s] [P PARALLEL] ❌ 140536644183696 -> The task was killed
[  25.659s] [P PARALLEL] ■ Finished -> 140536644183696
[  25.659s] [P PARALLEL] 💀 Killed -> 140536644181056
[  25.660s] [P PARALLEL] ❌ 140536644181056 -> The task was killed before it started
[  25.660s] [P PARALLEL] ■ Finished -> 140536644181056

AI Disclosure

AI tools claude used for generate the code

Details

🤖 Generated with Claude Code

Subprocess execution

Execute subprocess tasks with pebble.ProcessPool (new dependency) instead of ProcessPoolExecutor: a killed worker no longer breaks the pool.
- EwoksExecutor raises TypeError for a concurrent.futures.ProcessPoolExecutor.
- Orange-Spectroscopy uses pebble for the same reason: Peak Fit kills a running fit in a pebble.ProcessPool worker.
The worker installs its SIGINT handler only while the task executes. Elsewhere, pebble's workers ignore SIGINT.
While the task executes, its progress goes through a sender thread in the worker (at most 100 pending values), so an abort never interrupts a queue call.
- The progress an aborted task did not send yet is dropped.

Stopping a running task

Rename TaskFuture.abort/aborted → request_stop/stop_requested, and the aborted signal → stopRequested (not released yet).
- Cooperative: the task decides whether and how to stop.
- The stopRequested signal is emitted with the completion.
Add TaskFuture.abort(): interrupt like Ctrl-C. The task can clean up and the worker survives. Subprocess only.
Add TaskFuture.kill(): terminate the worker. No cleanup, the pool replaces the worker. Subprocess only.
Separate aborted and killed signals, and TaskFuture.aborted()/killed().

Queued and finished tasks

A queued task (waiting for a free worker) never starts after cancel(), request_stop(), abort() or kill() (abort() and kill(): process pool only). Its result() raises:
- CancelledError after cancel()
- TaskStoppedError after request_stop()
- TaskAbortedError after abort() or kill()
A task that is prevented from starting never emits aboutToStart or started.
Several calls on the same queued task: only the first counts, the others return False.
On a finished task all four do nothing and return False.

Signal order

The completion signals are emitted after the start and progress signals, also after kill() from the GUI thread.
- Except when a slot connected with Qt.DirectConnection delays the relay thread or calls kill().
Every submitted execution ends with finished: a cancelled task emits cancelled and finished (the widget no longer stays pending).
A failed submit() no longer leaves the executor busy.
- When it fails after the pool accepted the task, the task never starts and the execution ends with cancelled and finished.

Documentation

concurrency.rst: a contract for widget authors and corrected diagrams for maintainers.
New glossary.

Windows crash at exit

Fix a random crash (access violation in PyQt's exit cleanup) after the test session on Windows: the ewoksorange_qtapp teardown deletes the remaining Python-owned Qt objects.

Tests and demo

Tests cover cancel, stop, abort and kill on queued, running and finished tasks.
Executor demo script: cancel, request stop, abort and kill buttons.

codecov · 2026-10-14T03:39:27Z

Codecov Report

❌ Patch coverage is 78.00454% with 97 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...rc/ewoksorange/gui/concurrency/_runners/process.py	25.00%	60 Missing ⚠️
src/ewoksorange/gui/concurrency/_messages.py	61.66%	23 Missing ⚠️
...c/ewoksorange/gui/concurrency/_runners/abstract.py	82.05%	7 Missing ⚠️
...woksorange/gui/concurrency/_controllers/process.py	96.49%	2 Missing ⚠️
src/ewoksorange/gui/concurrency/executor.py	97.05%	2 Missing ⚠️
src/ewoksorange/gui/concurrency/future.py	95.00%	2 Missing ⚠️
src/ewoksorange/gui/owwidgets/base.py	85.71%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!

woutdenolf · 2026-10-14T15:14:08Z

+            return self._denial
+
+
 class TaskController(ABC):


Review tip: start by reading the docstrings of these changed class methods.

…op_requested Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

…ture.kill, and never start a queued task that is stopped, aborted or killed Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

…cts to avoid a crash at exit on Windows Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

…nd every execution with finished, and release a failed submission Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

…ng tasks

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

payno · 2026-10-19T08:01:54Z

I have trouble reviewing the PR to be honest (I am a human 🤣 ). Even with the tip.

This is too massive for me. I tried twice and even if a lot of it is tests I fail to review.
I understand the idea of moving to pebble but there is a lot of details I can't really properly follow because the changes touch several areas at once.

the first commit already reworks several things. Could we split this PR into several smaller ones (that can be on top of each others) - AI can probably do it ?

Here is a suggestion:

One with qt test fixes stuff (8b5f185, 62a026d)
One with renaiming: 329efdf
One for adding the startGate and the two queues (controller→runner and runner→controller.).
Moving to pebble (and potentially the kill)

woutdenolf changed the title ~~Use Task.request_stop and Task.stop_requested~~ Use the ewokscore stop API and rename abort to stop Oct 14, 2026

woutdenolf changed the title ~~Use the ewokscore stop API and rename abort to stop~~ Use the ewokscore stop API, rename abort to request_stop and add a real abort Oct 14, 2026

woutdenolf force-pushed the use_task_request_stop branch 3 times, most recently from bd36fbe to b30ecf5 Compare October 14, 2026 04:49

woutdenolf marked this pull request as draft October 14, 2026 05:24

woutdenolf changed the title ~~Use the ewokscore stop API, rename abort to request_stop and add a real abort~~ Use the ewokscore stop API, execute subprocess tasks with pebble, add abort and kill Oct 14, 2026

woutdenolf force-pushed the use_task_request_stop branch 6 times, most recently from 625bc0f to 3d4fbd7 Compare October 14, 2026 06:10

woutdenolf mentioned this pull request Oct 14, 2026

Adapt to Task.cancel now being deprecated. #490

Merged

1 task done

woutdenolf force-pushed the use_task_request_stop branch 2 times, most recently from f91d853 to f720b36 Compare October 14, 2026 15:06

woutdenolf changed the title ~~Use the ewokscore stop API, execute subprocess tasks with pebble, add abort and kill~~ Rename TaskFuture.abort to request_stop, execute subprocess tasks with pebble, add abort and kill Oct 14, 2026

woutdenolf commented Oct 14, 2026

View reviewed changes

Rename TaskFuture.abort and TaskFuture.aborted to request_stop and st…

329efdf

…op_requested Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

woutdenolf force-pushed the use_task_request_stop branch 10 times, most recently from 5f7266e to 3ef0155 Compare October 15, 2026 06:23

woutdenolf force-pushed the use_task_request_stop branch 2 times, most recently from 94942ee to 67f93e0 Compare October 15, 2026 06:29

woutdenolf and others added 2 commits October 15, 2026 08:33

Execute subprocess tasks with pebble, add TaskFuture.abort and TaskFu…

8b2379c

…ture.kill, and never start a queued task that is stopped, aborted or killed Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

ewoksorange_qtapp teardown: delete the remaining Python-owned Qt obje…

62a026d

…cts to avoid a crash at exit on Windows Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

woutdenolf force-pushed the use_task_request_stop branch 3 times, most recently from e271965 to 62bd8ba Compare October 15, 2026 07:16

EwoksExecutor: emit the completion signals after the start signals, e…

1ff4d61

…nd every execution with finished, and release a failed submission Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

woutdenolf force-pushed the use_task_request_stop branch from 62bd8ba to 151dcea Compare October 15, 2026 07:24

Doc: executor contract, corrected backend diagrams and a glossary

91ae215

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

woutdenolf force-pushed the use_task_request_stop branch from 151dcea to 91ae215 Compare October 15, 2026 07:26

test_owwidget_drop: do not depend on the duration of a task

8b5f185

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

woutdenolf force-pushed the use_task_request_stop branch 6 times, most recently from 58007eb to 08c86f3 Compare October 15, 2026 13:05

woutdenolf added 2 commits October 15, 2026 15:23

Executor demo: label the task actions as applying to queued and runni…

25e4480

…ng tasks

OWEwoksBaseWidget._create_pool_executor: also allow a pebble.ProcessPool

47f8682

woutdenolf force-pushed the use_task_request_stop branch from 08c86f3 to 7d07c0e Compare October 15, 2026 13:23

woutdenolf marked this pull request as ready for review October 15, 2026 13:57

woutdenolf requested a review from a team October 15, 2026 13:57

woutdenolf and others added 2 commits October 15, 2026 17:40

Process backend: name the endpoints controller and runner

2fbd8aa

Process backend: fix abort, kill and progress races

4ba8ca5

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

woutdenolf force-pushed the use_task_request_stop branch from 7d07c0e to 4ba8ca5 Compare October 15, 2026 15:40

woutdenolf added this to the v6.0.0 milestone Oct 19, 2026

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Rename TaskFuture.abort to request_stop, execute subprocess tasks with pebble, add abort and kill - #501

Rename TaskFuture.abort to request_stop, execute subprocess tasks with pebble, add abort and kill#501
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PR summary

AI Disclosure

Details

Subprocess execution

Stopping a running task

Queued and finished tasks

Signal order

Documentation

Windows crash at exit

Tests and demo

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