gh-104090: Update Resource Tracker to return exit code based on resource leaked found or not #106807

bityob · 2023-07-16T11:55:32Z

Add tests to catch the resource leak bug in collectedDurations and verified that it fails without the fix

Show output

$ ./python -m unittest test.test_concurrent_futures.FailingInitializerResourcesTest
.
/home/user/cpython/Lib/multiprocessing/resource_tracker.py:228: UserWarning: resource_tracker: There appear to be 3 leaked semaphore objects to clean up at shutdown
  warnings.warn('resource_tracker: There appear to be %d '
FTraceback (most recent call last):
  File "/home/user/cpython/Lib/multiprocessing/util.py", line 300, in _run_finalizers
    finalizer()
  File "/home/user/cpython/Lib/multiprocessing/util.py", line 224, in __call__
    res = self._callback(*self._args, **self._kwargs)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup
    sem_unlink(name)
FileNotFoundError: [Errno 2] No such file or directory
.
.
.
======================================================================
FAIL: test_forkserver (test.test_concurrent_futures.FailingInitializerResourcesTest.test_forkserver)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/user/cpython/Lib/test/test_concurrent_futures.py", line 318, in test_forkserver
    self._test(ProcessPoolForkserverFailingInitializerTest)
  File "/home/user/cpython/Lib/test/test_concurrent_futures.py", line 312, in _test
    self.assertEqual(_resource_tracker._exitcode, 0)
AssertionError: 256 != 0

======================================================================
FAIL: test_spawn (test.test_concurrent_futures.FailingInitializerResourcesTest.test_spawn)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/user/cpython/Lib/test/test_concurrent_futures.py", line 315, in test_spawn
    self._test(ProcessPoolSpawnFailingInitializerTest)
  File "/home/user/cpython/Lib/test/test_concurrent_futures.py", line 312, in _test
    self.assertEqual(_resource_tracker._exitcode, 0)
AssertionError: 256 != 0

----------------------------------------------------------------------
Ran 2 tests in 0.727s

FAILED (failures=2)
0.33s

Add returning exit code from resource_tracker.py based on the cleanup result, so we can check what was the result
Add tests for Resource Tracker exit code based on leaked/no leaked resources

Issue: Leaked semaphore objects in test_concurrent_futures #104090

…r not and added tests for that

bedevere-bot · 2023-07-16T11:55:36Z

Most changes to Python require a NEWS entry.

Please add it using the blurb_it web app or the blurb command-line tool.

Lib/multiprocessing/resource_tracker.py

Lib/test/_test_multiprocessing.py

…_concurrent_futures-v2

pitrou · 2023-07-17T16:24:42Z

Lib/test/_test_multiprocessing.py

+
+        # Reset exit code value
+        _resource_tracker._exitcode = None
+        exit_code_assert = self.assertNotEqual


This is a bit confusing. Also, it will match any non-zero exit code which might not be desired (other problems may return some code not in {0, 1}). How about simply expected_exit_code = 0 if delete_queue else 1?

Hey,
I fixed the test and fixed the code too.
Since I saved the exit status (which was 256 when the exit code was 1),
so now the code saves the exit code and verifies it to 0/1
Thanks

Lib/test/_test_multiprocessing.py

pitrou · 2023-07-17T16:27:53Z

Lib/test/test_concurrent_futures.py

+        runner = unittest.TextTestRunner()
+        result = runner.run(test_class('test_initializer'))
+
+        self.assertEqual(result.testsRun, 1)
+        self.assertEqual(result.failures, [])
+        self.assertEqual(result.errors, [])


Uhm, why not do the simple thing and add these checks somewhere in FailingInitializerMixin?
It should also avoid running those tests twice (which I assume this does).

The result object exists when we run the test using Test Runner, which is not the case on FailingInitializerMixin.
This is used for safety, ensuring the inner test passed before we check the resource tracker

Yes, but this is needlessly complex (and might interfere with other test options/customizations). Let's do the check at the end of said tests.

@pitrou I don't understand how you want those checks to be since we can check it only after a test run with the returned result, which is not the case in regular tests. Anyway, I'm removing those checks since it's not mandatory and just for safety

I honestly don't understand what the difficulty would be. You can make the resource tracker stop at the end of the test, or at the end of the testcase (in a teardown method for example).

… to convert from status code to exit code

…_concurrent_futures-v2

Lib/test/_test_multiprocessing.py

pitrou · 2023-07-18T10:00:41Z

Lib/test/_test_multiprocessing.py

+        Test the exit code of the resource tracker based on if there were left leaked resources when we stop the process.
+        If not leaked resources were found, exit code should be 0, otherwise 1


Thanks for the comment. Nit, but can you please ensure the line length remains reasonable (say < 80 characters) ? This can otherwise be annoying when reading/reviewing code.

Yes, I'll fix it. I'm used to 120 chars line length...

Misc/NEWS.d/next/Core and Builtins/2023-07-16-15-02-47.gh-issue-104090.oMjNa9.rst

Lib/multiprocessing/resource_tracker.py

Lib/test/_test_multiprocessing.py

…collect

…_concurrent_futures-v2

sunmy2019 · 2023-07-19T08:02:27Z

We should get #106795 merged first to pass the test.

pitrou · 2023-07-19T08:11:55Z

Lib/test/test_concurrent_futures.py

+        runner = unittest.TextTestRunner()
+        runner.run(test_class('test_initializer'))


Again, can you please instead put these checks directly in FailingInitializerMixin?
For example, add a tearDown method:

def tearDown(self): super().tearDown() # shutdown executor if self.mp_context and self.mp_context.get_start_method() in ("spawn", "forkserver"): # Stop resource tracker manually now, so we can verify there are # not leaked resources by checking the process exit code from multiprocessing.resource_tracker import _resource_tracker _resource_tracker._stop() self.assertEqual(_resource_tracker._exitcode, 0)

@pitrou Checking

Doesn't work

$ ./python -m unittest test.test_concurrent_futures.ProcessPoolForkserverFailingInitializerTest -v test_initializer (test.test_concurrent_futures.ProcessPoolForkserverFailingInitializerTest.test_initializer) ... /home/user/cpython/Lib/multiprocessing/resource_tracker.py:236: UserWarning: resource_tracker: There appear to be 3 leaked semaphore objects to clean up at shutdown warnings.warn('resource_tracker: There appear to be %d ' FAIL Traceback (most recent call last): File "/home/user/cpython/Lib/multiprocessing/util.py", line 300, in _run_finalizers finalizer() File "/home/user/cpython/Lib/multiprocessing/util.py", line 224, in __call__ res = self._callback(*self._args, **self._kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/user/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup sem_unlink(name) FileNotFoundError: [Errno 2] No such file or directory Traceback (most recent call last): File "/home/user/cpython/Lib/multiprocessing/util.py", line 300, in _run_finalizers finalizer() File "/home/user/cpython/Lib/multiprocessing/util.py", line 224, in __call__ res = self._callback(*self._args, **self._kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/user/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup sem_unlink(name) FileNotFoundError: [Errno 2] No such file or directory Traceback (most recent call last): File "/home/user/cpython/Lib/multiprocessing/util.py", line 300, in _run_finalizers finalizer() File "/home/user/cpython/Lib/multiprocessing/util.py", line 224, in __call__ res = self._callback(*self._args, **self._kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/user/cpython/Lib/multiprocessing/synchronize.py", line 87, in _cleanup sem_unlink(name) FileNotFoundError: [Errno 2] No such file or directory ====================================================================== FAIL: test_initializer (test.test_concurrent_futures.ProcessPoolForkserverFailingInitializerTest.test_initializer) ---------------------------------------------------------------------- Traceback (most recent call last): File "/home/user/cpython/Lib/test/test_concurrent_futures.py", line 298, in tearDown self.assertEqual(_resource_tracker._exitcode, 0) AssertionError: 1 != 0 ---------------------------------------------------------------------- Ran 1 test in 0.269s FAILED (failures=1)

Hmm, too bad :-(

…_concurrent_futures-v2

…_futures-v2' of github.com:bityob/cpython into pythongh-104090-fix-leaked-semaphors-on-test_concurrent_futures-v2

…_concurrent_futures-v2

bityob · 2023-08-03T20:45:42Z

@pitrou
Hey,
Can you review again?
Thanks

pitrou · 2023-08-31T13:20:38Z

@bityob Sorry for the delay. There were some recent changes in git main that are causing conflicts. Could you merge from main and fix the conflicts? Thank you!

…est_concurrent_futures.py) to new location (Lib/test/test_concurrent_futures/test_init.py)

…_futures-v2' of github.com:bityob/cpython into pythongh-104090-fix-leaked-semaphors-on-test_concurrent_futures-v2

bityob · 2023-08-31T17:39:19Z

@bityob Sorry for the delay. There were some recent changes in git main that are causing conflicts. Could you merge from main and fix the conflicts? Thank you!

Hey @pitrou, Thank you!

I merged the main branch and resolved all conflicts.

Please review again

…_concurrent_futures-v2

pitrou

Thanks @bityob for the update. LGTM now, let's wait for CI.

pitrou · 2023-09-19T11:14:01Z

Unfortunately there are CI failures which look related. Can you take a look?

bityob · 2023-09-21T13:04:45Z

Unfortunately there are CI failures which look related. Can you take a look?

Yes, thanks. I'll check

Updated Resource Tracker to return exit code based on leaking found o…

70a35a2

…r not and added tests for that

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Leaked semaphore objects in test_concurrent_futures #104090

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bityob mentioned this pull request Jul 16, 2023

gh-104090: Fix unittest collectedDurations resources leak #106795

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bityob added 2 commits July 17, 2023 18:48

Use subTest for the parametrize the same tests with different values

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bityob added 4 commits July 18, 2023 12:03

Updated tests based on PR comments, and fix the resource_tracker code…

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… to convert from status code to exit code

Clean test

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Added comment for test and simplified the logic

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bityob and others added 4 commits July 18, 2023 13:38

Fix tests and News based on PR comments

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Added reseting the exit code when the process should run again

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Added more clearing queue methods beside del (closing and calling gc.…

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bityob added 3 commits August 31, 2023 20:32

Merge main

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pitrou changed the title ~~gh-104090: Updated Resource Tracker to return exit code based on resource leaked found or not~~ gh-104090: Update Resource Tracker to return exit code based on resource leaked found or not Sep 19, 2023

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gh-104090: Update Resource Tracker to return exit code based on resource leaked found or not #106807

gh-104090: Update Resource Tracker to return exit code based on resource leaked found or not #106807

bityob commented Jul 16, 2023 •

edited by pitrou

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bityob commented Sep 21, 2023

		Test the exit code of the resource tracker based on if there were left leaked resources when we stop the process.
		If not leaked resources were found, exit code should be 0, otherwise 1

		runner = unittest.TextTestRunner()
		runner.run(test_class('test_initializer'))

gh-104090: Update Resource Tracker to return exit code based on resource leaked found or not #106807

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gh-104090: Update Resource Tracker to return exit code based on resource leaked found or not #106807

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bityob commented Jul 16, 2023 • edited by pitrou

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bityob commented Jul 16, 2023 •

edited by pitrou