diff --git a/Doc/library/logging.handlers.rst b/Doc/library/logging.handlers.rst index 5a081f9e7add99..e63c253e123552 100644 --- a/Doc/library/logging.handlers.rst +++ b/Doc/library/logging.handlers.rst @@ -1172,6 +1172,10 @@ possible, while any potentially slow operations (such as sending an email via This starts up a background thread to monitor the queue for LogRecords to process. + .. versionchanged:: next + Raises :exc:`RuntimeError` if called and the listener is already + running. + .. method:: stop() Stops the listener. diff --git a/Lib/logging/handlers.py b/Lib/logging/handlers.py index da9c59c119f3db..d3ea06c731ef89 100644 --- a/Lib/logging/handlers.py +++ b/Lib/logging/handlers.py @@ -1545,6 +1545,9 @@ def start(self): This starts up a background thread to monitor the queue for LogRecords to process. """ + if self._thread is not None: + raise RuntimeError("Listener already started") + self._thread = t = threading.Thread(target=self._monitor) t.daemon = True t.start() diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py index 678c23dad67faa..58e0381c4aa934 100644 --- a/Lib/test/test_logging.py +++ b/Lib/test/test_logging.py @@ -4300,8 +4300,6 @@ def test_formatting(self): self.assertEqual(formatted_msg, log_record.msg) self.assertEqual(formatted_msg, log_record.message) - @unittest.skipUnless(hasattr(logging.handlers, 'QueueListener'), - 'logging.handlers.QueueListener required for this test') def test_queue_listener(self): handler = TestHandler(support.Matcher()) listener = logging.handlers.QueueListener(self.queue, handler) @@ -4336,8 +4334,18 @@ def test_queue_listener(self): self.assertTrue(handler.matches(levelno=logging.CRITICAL, message='6')) handler.close() - @unittest.skipUnless(hasattr(logging.handlers, 'QueueListener'), - 'logging.handlers.QueueListener required for this test') + # doesn't hurt to call stop() more than once. + listener.stop() + self.assertIsNone(listener._thread) + + def test_queue_listener_multi_start(self): + handler = TestHandler(support.Matcher()) + listener = logging.handlers.QueueListener(self.queue, handler) + listener.start() + self.assertRaises(RuntimeError, listener.start) + listener.stop() + self.assertIsNone(listener._thread) + def test_queue_listener_with_StreamHandler(self): # Test that traceback and stack-info only appends once (bpo-34334, bpo-46755). listener = logging.handlers.QueueListener(self.queue, self.root_hdlr) @@ -4352,8 +4360,6 @@ def test_queue_listener_with_StreamHandler(self): self.assertEqual(self.stream.getvalue().strip().count('Traceback'), 1) self.assertEqual(self.stream.getvalue().strip().count('Stack'), 1) - @unittest.skipUnless(hasattr(logging.handlers, 'QueueListener'), - 'logging.handlers.QueueListener required for this test') def test_queue_listener_with_multiple_handlers(self): # Test that queue handler format doesn't affect other handler formats (bpo-35726). self.que_hdlr.setFormatter(self.root_formatter) diff --git a/Misc/NEWS.d/next/Library/2025-04-12-09-30-24.gh-issue-132106.OxUds3.rst b/Misc/NEWS.d/next/Library/2025-04-12-09-30-24.gh-issue-132106.OxUds3.rst new file mode 100644 index 00000000000000..b6d58a29f9b42f --- /dev/null +++ b/Misc/NEWS.d/next/Library/2025-04-12-09-30-24.gh-issue-132106.OxUds3.rst @@ -0,0 +1,2 @@ +:meth:`QueueListener.start ` now +raises a :exc:`RuntimeError` if the listener is already started.