Enhancement: Add feature to manually retry failed task by yashpapa6969 · Pull Request #1417 · mher/flower

yashpapa6969 · 2024-12-26T07:57:25Z

Change Log

API Update: Introduced the TaskReapply endpoint to reapply tasks with original arguments.
Error Handling: Ensures JSON-serializable arguments and robust error logging.
Backend Utilities: Added helper functions (parse_args, parse_kwargs, make_json_serializable) for argument parsing and serialization.

iloveitaly · 2025-01-21T22:30:26Z

@mher anything I can do to help get this merged?

flower/utils/tasks.py

…d security

flower/utils/tasks.py

sc68cal

My concerns have been addressed, thank you for this contribution!

yashpapa6969 · 2025-02-02T17:03:05Z

@sc68cal how can i get this merged?

sc68cal · 2025-02-02T19:03:08Z

@sc68cal how can i get this merged?

I am not the maintainer, the maintainer needs to approve and merge

marcus-campos

Awesome!

Ragnarow · 2025-02-05T17:48:39Z

Thanks for the feature, @mher could we get this merged?

matias-martini · 2025-02-14T17:40:03Z

Hi! Thanks for adding this awesome feature @yashpapa6969 ! I tested it locally and noticed a small issue: I think we need to add a route for the new controller in flower/urls.py:

    (r"/api/task/reapply/(.+)", tasks.TaskReapply),

Otherwise the Retry button will fail with 404

yashpapa6969 · 2025-02-14T17:50:27Z

@matias-martini thank you updated

matias-martini · 2025-02-14T17:57:20Z

@yashpapa6969 Thanks for the updates! 🙌

Would you mind adding a test for the new API endpoint? It'll help ensure we cover the most common cases.

Ragnarow · 2025-03-18T22:27:48Z

@yashpapa6969 Thanks for the effort, can we have the tests to merge this?

the-rich-piana · 2025-08-05T16:05:12Z

Any update on this?

alexandercarruthers · 2025-08-18T11:16:24Z

Would be great to see this feature merged !

auvipy

this will also need unit tests to avoid regression

mihai-burduselu-ptt · 2025-09-09T15:14:12Z

@yashpapa6969, thank you so much for the effort! Could you help us with the tests for it so we can review and merge?

bondbenz · 2026-01-07T11:06:11Z

hello, any updates on this? thanks

Copilot

Pull request overview

This PR adds a new feature to manually retry failed tasks through the Flower UI and API. It introduces a /api/task/reapply/{taskid} endpoint that retrieves a failed task's original arguments and reapplies it as a new task.

Key Changes:

Added TaskReapply API endpoint to reapply tasks with their original arguments
Implemented utility functions (parse_args, parse_kwargs, make_json_serializable) to handle argument parsing and JSON serialization
Added a "Retry" button in the UI for tasks in FAILURE state

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 14 comments.

Show a summary per file

File	Description
flower/api/tasks.py	Implements the new TaskReapply endpoint handler with error handling and task reapplication logic
flower/utils/tasks.py	Adds helper functions for parsing task arguments from various formats (JSON, Python literals) and ensuring JSON serializability
flower/urls.py	Registers the new /api/task/reapply endpoint route
flower/templates/task.html	Adds a "Retry" button for failed tasks in the task detail page
flower/static/js/flower.js	Implements client-side logic to handle retry button clicks and API communication
tests/unit/api/test_tasks.py	Adds comprehensive test coverage for the TaskReapply endpoint covering success, error cases, and edge cases

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Copilot · 2026-01-07T12:16:57Z

flower/utils/tasks.py

+        if args.startswith('(') and args.endswith(')'):
+            return ast.literal_eval(args)


Security concern: Using ast.literal_eval on user-provided input (task.args) could be dangerous. While ast.literal_eval is safer than eval, it still executes Python code parsing. If an attacker can control the stored task.args value, they might craft malicious input. Consider restricting to JSON-only parsing or implementing additional validation before using ast.literal_eval.

Copilot · 2026-01-07T12:16:57Z

flower/utils/tasks.py

+    except (json.JSONDecodeError, SyntaxError):
+        # Fallback for stringified tuples or ellipsis
+        if args == '...':
+            return [...]


Returning a list containing an Ellipsis object is problematic. The Ellipsis object (...) is typically used as a placeholder but returning it wrapped in a list can cause issues downstream. Consider returning an empty list or raising a ValueError to indicate that '...' is not a valid argument format.

Suggested change

return [...]

return []

Copilot · 2026-01-07T12:16:57Z

flower/static/js/flower.js

+            type: 'POST',
+            url: url_prefix() + '/api/task/reapply/' + taskId,
+            success: function (response) {
+                show_alert(`Task ${taskId} has been retried (new task ID: ${response['task-id']})`, 'success');


Missing error handling for empty or undefined response. The success callback accesses response['task-id'] without verifying that the response object exists or contains the 'task-id' key. If the API returns an unexpected response structure, this could cause a runtime error.

Suggested change

show_alert(`Task ${taskId} has been retried (new task ID: ${response['task-id']})`, 'success');

var newTaskId = response && typeof response === 'object' ? response['task-id'] : undefined;

if (newTaskId) {

show_alert(`Task ${taskId} has been retried (new task ID: ${newTaskId})`, 'success');

} else {

show_alert(`Task ${taskId} has been retried.`, 'success');

}

Copilot · 2026-01-07T12:16:57Z

flower/api/tasks.py

+        :param taskid: ID of the task to reapply.
+        """
+        # Get original task info
+        task = tasks.get_task_by_id(self.application.events, taskid)


Missing input validation: The taskid parameter from the URL is used directly without validation. Consider validating that taskid matches expected UUID format to prevent potential injection issues or unnecessary processing of invalid task IDs.

Copilot · 2026-01-07T12:16:58Z

flower/api/tasks.py

+        Get task info and reapply the task with the same arguments.
+
+        :param taskid: ID of the task to reapply.


Missing API documentation: The TaskReapply endpoint lacks comprehensive API documentation that other endpoints in this file have (such as TaskInfo). Consider adding proper docstring documentation including HTTP method, example request/response, parameters description, and status codes.

Suggested change

Get task info and reapply the task with the same arguments.

:param taskid: ID of the task to reapply.

Reapply a previously executed task using the same arguments.

This endpoint retrieves an existing task by its ID, extracts its original

positional and keyword arguments, and submits a new task with the same

name and arguments. A new task ID is returned for the re-applied task.

**Example request**:

.. sourcecode:: http

POST /api/task/reapply/7b3b9f52-1af3-4e0c-8a8a-5a5f9c2f8c64 HTTP/1.1

Host: localhost

Accept: application/json

Cookie: user=...

**Example response**:

.. sourcecode:: http

HTTP/1.1 200 OK

Content-Type: application/json

{

"task-id": "c1a2b3d4-5678-90ab-cdef-1234567890ab",

"state": "PENDING"

}

:param str taskid: ID of the original task to reapply.

:statuscode 200: task successfully reapplied; returns new task ID and state (if backend configured)

:statuscode 400: invalid task arguments or original task has no name

:statuscode 401: unauthorized request

:statuscode 404: unknown task ID or unknown task name

:statuscode 500: internal error while reapplying the task

Copilot · 2026-01-07T12:16:59Z

tests/unit/api/test_tasks.py

+            r = self.post('/api/task/reapply/123', body='')
+
+        self.assertEqual(200, r.code)
+        task.apply_async.assert_called_once_with(args=[None], kwargs={})


The test expects args=[None] when '...' is parsed, but according to the parse_args implementation on line 89 of flower/utils/tasks.py, it returns [Ellipsis] (a list containing the Ellipsis object), not [None]. This test will fail unless make_json_serializable is called, which converts Ellipsis to None. The test should verify the actual behavior or mock make_json_serializable.

Suggested change

task.apply_async.assert_called_once_with(args=[None], kwargs={})

task.apply_async.assert_called_once_with(args=[Ellipsis], kwargs={})

flower/api/tasks.py

Copilot · 2026-01-07T12:17:00Z

flower/api/tasks.py

+        except Exception as exc:
+            logger.error("Error reapplying task with args=%s, kwargs=%s: %s", args, kwargs, str(exc))
+            raise HTTPError(500, f"Error reapplying task: {str(exc)}") from exc


Using broad exception handling with 'Exception' can mask unexpected errors and make debugging difficult. The try block contains multiple operations (make_json_serializable, apply_async, response creation) and catching all exceptions makes it unclear what specific failure occurred. Consider using more specific exception types or separating error handling for different operations.

flower/utils/tasks.py

Copilot · 2026-01-07T12:17:00Z

flower/utils/tasks.py

+    if isinstance(obj, list):
+        return [make_json_serializable(item) for item in obj]
+    elif isinstance(obj, dict):
+        return {key: make_json_serializable(value) for key, value in obj.items()}


The function has incomplete handling of non-serializable types. While it handles Ellipsis, list, and dict, it doesn't handle other common non-serializable types like tuples, sets, datetime objects, or custom objects. Tuples should be converted to lists for JSON serialization, and other types may need special handling or should raise an error to alert callers of serialization issues.

Suggested change

if isinstance(obj, list):

return [make_json_serializable(item) for item in obj]

elif isinstance(obj, dict):

return {key: make_json_serializable(value) for key, value in obj.items()}

if isinstance(obj, (list, tuple, set)):

# Convert tuples and sets to lists, and recurse into all sequence elements

return [make_json_serializable(item) for item in obj]

elif isinstance(obj, dict):

return {key: make_json_serializable(value) for key, value in obj.items()}

elif isinstance(obj, (datetime.datetime, datetime.date, datetime.time)):

# Represent datetime-like objects as ISO 8601 strings

return obj.isoformat()

auvipy

please cross check the review comments carefully

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

yashpapa6969 · 2026-01-07T13:09:18Z

okay

Enhancement: Addfeature to manually retry failed task

81c2836

iloveitaly mentioned this pull request Jan 21, 2025

[FEATURE] Option to retry a failed task #1348

Open

sc68cal reviewed Jan 22, 2025

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flower/utils/tasks.py Outdated Show resolved Hide resolved

Replace eval with ast.literal_eval in parse_args function for improve…

cf3b790

…d security

yashpapa6969 requested a review from sc68cal January 25, 2025 16:31

sc68cal reviewed Jan 26, 2025

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flower/utils/tasks.py Outdated Show resolved Hide resolved

Security: refactored code

012e958

yashpapa6969 requested a review from sc68cal January 26, 2025 14:04

sc68cal approved these changes Jan 28, 2025

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marcus-campos approved these changes Feb 3, 2025

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fix adding route for the controller TaskReapply

bc0b8e3

symbiotech approved these changes Feb 21, 2025

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alexandercarruthers approved these changes Aug 18, 2025

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auvipy requested changes Aug 18, 2025

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mdamire approved these changes Sep 22, 2025

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alex-goswag approved these changes Sep 23, 2025

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kelvin5290 approved these changes Dec 22, 2025

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yashpapa6969 and others added 2 commits December 22, 2025 12:39

Merge branch 'mher:master' into master

6966ae8

Add unit tests for task reapplication functionality

323474e

yashpapa6969 requested a review from auvipy December 22, 2025 07:43

auvipy requested a review from Copilot January 7, 2026 12:11

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auvipy requested changes Jan 7, 2026

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auvipy and others added 2 commits January 7, 2026 18:27

Update flower/utils/tasks.py

a550f13

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Update flower/api/tasks.py

598c274

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

		if args.startswith('(') and args.endswith(')'):
		return ast.literal_eval(args)

-                show_alert(`Task ${taskId} has been retried (new task ID: ${response['task-id']})`, 'success');
+                var newTaskId = response && typeof response === 'object' ? response['task-id'] : undefined;
+                if (newTaskId) {
+                    show_alert(`Task ${taskId} has been retried (new task ID: ${newTaskId})`, 'success');
+                } else {
+                    show_alert(`Task ${taskId} has been retried.`, 'success');
+                }

		Get task info and reapply the task with the same arguments.

		:param taskid: ID of the task to reapply.

-        Get task info and reapply the task with the same arguments.
-        :param taskid: ID of the task to reapply.
+        Reapply a previously executed task using the same arguments.
+        This endpoint retrieves an existing task by its ID, extracts its original
+        positional and keyword arguments, and submits a new task with the same
+        name and arguments. A new task ID is returned for the re-applied task.
+        **Example request**:
+        .. sourcecode:: http
+           POST /api/task/reapply/7b3b9f52-1af3-4e0c-8a8a-5a5f9c2f8c64 HTTP/1.1
+           Host: localhost
+           Accept: application/json
+           Cookie: user=...
+        **Example response**:
+        .. sourcecode:: http
+           HTTP/1.1 200 OK
+           Content-Type: application/json
+           {
+             "task-id": "c1a2b3d4-5678-90ab-cdef-1234567890ab",
+             "state": "PENDING"
+           }
+        :param str taskid: ID of the original task to reapply.
+        :statuscode 200: task successfully reapplied; returns new task ID and state (if backend configured)
+        :statuscode 400: invalid task arguments or original task has no name
+        :statuscode 401: unauthorized request
+        :statuscode 404: unknown task ID or unknown task name
+        :statuscode 500: internal error while reapplying the task

	task.apply_async.assert_called_once_with(args=[None], kwargs={})
	task.apply_async.assert_called_once_with(args=[Ellipsis], kwargs={})

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yashpapa6969 commented Dec 26, 2024

Change Log

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mihai-burduselu-ptt commented Sep 9, 2025 •

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