fix: do not use get_event_loop in GunicornWebWorker - 3.13 (#12057)

Author: Tasssadar

CHANGES/11701.bugfix.rst

@@ -0,0 +1,3 @@
+Fixed ``RuntimeError: An event loop is running`` error when using ``aiohttp.GunicornWebWorker``
+or ``aiohttp.GunicornUVLoopWebWorker`` on Python >=3.14.
+-- by :user:`Tasssadar`.

aiohttp/worker.py

@@ -36,7 +36,6 @@
 
 
 class GunicornWebWorker(base.Worker):  # type: ignore[misc,no-any-unimported]
-
     DEFAULT_AIOHTTP_LOG_FORMAT = AccessLogger.LOG_FORMAT
     DEFAULT_GUNICORN_LOG_FORMAT = GunicornAccessLogFormat.default
 
@@ -49,7 +48,11 @@ def __init__(self, *args: Any, **kw: Any) -> None:  # pragma: no cover
 
     def init_process(self) -> None:
         # create new event_loop after fork
-        asyncio.get_event_loop().close()
+        try:
+            asyncio.get_event_loop().close()
+        except RuntimeError:
+            # No loop was running
+            pass
 
         self.loop = asyncio.new_event_loop()
         asyncio.set_event_loop(self.loop)
@@ -245,7 +248,11 @@ def init_process(self) -> None:
 
         # Close any existing event loop before setting a
         # new policy.
-        asyncio.get_event_loop().close()
+        try:
+            asyncio.get_event_loop().close()
+        except RuntimeError:
+            # No loop was running
+            pass
 
         # Setup uvloop policy, so that every
         # asyncio.get_event_loop() will create an instance

tests/test_worker.py

@@ -46,7 +46,8 @@ class AsyncioWorker(BaseTestWorker, base_worker.GunicornWebWorker):  # type: ign
 if uvloop is not None:
 
     class UvloopWorker(
-        BaseTestWorker, base_worker.GunicornUVLoopWebWorker  # type: ignore
+        BaseTestWorker,
+        base_worker.GunicornUVLoopWebWorker,  # type: ignore
     ):
         pass
 
@@ -75,6 +76,22 @@ def test_init_process(worker: base_worker.GunicornWebWorker) -> None:
         assert m_asyncio.set_event_loop.called
 
 
+def test_init_process_no_loop(worker: base_worker.GunicornWebWorker) -> None:
+    with mock.patch("aiohttp.worker.asyncio") as m_asyncio:
+        m_asyncio.get_event_loop.side_effect = RuntimeError(
+            "There is no current event loop in thread 'MainThread'"
+        )
+        try:
+            worker.init_process()
+        except TypeError:
+            pass
+
+        assert m_asyncio.get_event_loop.called
+        assert not m_asyncio.get_event_loop.return_value.close.called
+        assert m_asyncio.new_event_loop.called
+        assert m_asyncio.set_event_loop.called
+
+
 def test_run(
     worker: base_worker.GunicornWebWorker, loop: asyncio.AbstractEventLoop
 ) -> None: