Limit executor imports to a single thread (#111898)

* Limit executor imports to a single thread

* test for import executor

* test for import executor

* test for import executor

* fixes

* better fix

homeassistant/core.py

@@ -95,6 +95,7 @@ from .util.async_ import (
     run_callback_threadsafe,
     shutdown_run_callback_threadsafe,
 )
+from .util.executor import InterruptibleThreadPoolExecutor
 from .util.json import JsonObjectType
 from .util.read_only_dict import ReadOnlyDict
 from .util.timeout import TimeoutManager
@@ -394,6 +395,9 @@ class HomeAssistant:
         self.timeout: TimeoutManager = TimeoutManager()
         self._stop_future: concurrent.futures.Future[None] | None = None
         self._shutdown_jobs: list[HassJobWithArgs] = []
+        self.import_executor = InterruptibleThreadPoolExecutor(
+            max_workers=1, thread_name_prefix="ImportExecutor"
+        )
 
     @cached_property
     def is_running(self) -> bool:
@@ -678,6 +682,16 @@ class HomeAssistant:
 
         return task
 
+    @callback
+    def async_add_import_executor_job(
+        self, target: Callable[..., _T], *args: Any
+    ) -> asyncio.Future[_T]:
+        """Add an import executor job from within the event loop."""
+        task = self.loop.run_in_executor(self.import_executor, target, *args)
+        self._tasks.add(task)
+        task.add_done_callback(self._tasks.remove)
+        return task
+
     @overload
     @callback
     def async_run_hass_job(
@@ -992,6 +1006,7 @@ class HomeAssistant:
             self._async_log_running_tasks("close")
 
         self.set_state(CoreState.stopped)
+        self.import_executor.shutdown()
 
         if self._stopped is not None:
             self._stopped.set()

homeassistant/loader.py

@@ -853,7 +853,7 @@ class Integration:
         # So we do it before validating config to catch these errors.
         if load_executor:
             try:
-                comp = await self.hass.async_add_executor_job(self.get_component)
+                comp = await self.hass.async_add_import_executor_job(self.get_component)
             except ImportError as ex:
                 load_executor = False
                 _LOGGER.debug("Failed to import %s in executor", domain, exc_info=ex)
@@ -924,7 +924,7 @@ class Integration:
         try:
             if load_executor:
                 try:
-                    platform = await self.hass.async_add_executor_job(
+                    platform = await self.hass.async_add_import_executor_job(
                         self._load_platform, platform_name
                     )
                 except ImportError as ex:

tests/components/zwave_js/test_update.py

@@ -310,7 +310,7 @@ async def test_update_entity_ha_not_running(
     hass_ws_client: WebSocketGenerator,
 ) -> None:
     """Test update occurs only after HA is running."""
-    await hass.async_stop()
+    hass.set_state(CoreState.not_running)
 
     client.async_send_command.return_value = {"updates": []}
 
@@ -632,7 +632,7 @@ async def test_update_entity_delay(
     """Test update occurs on a delay after HA starts."""
     client.async_send_command.reset_mock()
     client.async_send_command.return_value = {"updates": []}
-    await hass.async_stop()
+    hass.set_state(CoreState.not_running)
 
     entry = MockConfigEntry(domain="zwave_js", data={"url": "ws://test.org"})
     entry.add_to_hass(hass)

tests/test_core.py

@@ -2869,3 +2869,19 @@ def test_one_time_listener_repr(hass: HomeAssistant) -> None:
     assert "OneTimeListener" in repr_str
     assert "test_core" in repr_str
     assert "_listener" in repr_str
+
+
+async def test_async_add_import_executor_job(hass: HomeAssistant) -> None:
+    """Test async_add_import_executor_job works and is limited to one thread."""
+    evt = threading.Event()
+    loop = asyncio.get_running_loop()
+
+    def executor_func() -> None:
+        evt.set()
+        return evt
+
+    future = hass.async_add_import_executor_job(executor_func)
+    await loop.run_in_executor(None, evt.wait)
+    assert await future is evt
+
+    assert hass.import_executor._max_workers == 1