Use lock in Camera.create_stream (#62757)

Rename create_stream to async_create_stream in Camera
Rename get_image to async_get_image in Stream
Rename get_image to async_get_image in KeyFrameConverter

homeassistant/components/camera/__init__.py

@@ -312,7 +312,7 @@ async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
             camera_prefs = prefs.get(camera.entity_id)
             if not camera_prefs.preload_stream:
                 continue
-            stream = await camera.create_stream()
+            stream = await camera.async_create_stream()
             if not stream:
                 continue
             stream.keepalive = True
@@ -390,6 +390,7 @@ class Camera(Entity):
         self.access_tokens: collections.deque = collections.deque([], 2)
         self._warned_old_signature = False
         self.async_update_token()
+        self._create_stream_lock: asyncio.Lock | None = None
 
     @property
     def entity_picture(self) -> str:
@@ -454,22 +455,25 @@ class Camera(Entity):
             return self.stream.available
         return super().available
 
-    async def create_stream(self) -> Stream | None:
+    async def async_create_stream(self) -> Stream | None:
         """Create a Stream for stream_source."""
         # There is at most one stream (a decode worker) per camera
-        if not self.stream:
-            async with async_timeout.timeout(CAMERA_STREAM_SOURCE_TIMEOUT):
-                source = await self.stream_source()
-            if not source:
-                return None
-            self.stream = create_stream(
-                self.hass,
-                source,
-                options=self.stream_options,
-                stream_label=self.entity_id,
-            )
-            self.stream.set_update_callback(self.async_write_ha_state)
-        return self.stream
+        if not self._create_stream_lock:
+            self._create_stream_lock = asyncio.Lock()
+        async with self._create_stream_lock:
+            if not self.stream:
+                async with async_timeout.timeout(CAMERA_STREAM_SOURCE_TIMEOUT):
+                    source = await self.stream_source()
+                if not source:
+                    return None
+                self.stream = create_stream(
+                    self.hass,
+                    source,
+                    options=self.stream_options,
+                    stream_label=self.entity_id,
+                )
+                self.stream.set_update_callback(self.async_write_ha_state)
+            return self.stream
 
     async def stream_source(self) -> str | None:
         """Return the source of the stream.
@@ -918,7 +922,7 @@ async def async_handle_play_stream_service(
 async def _async_stream_endpoint_url(
     hass: HomeAssistant, camera: Camera, fmt: str
 ) -> str:
-    stream = await camera.create_stream()
+    stream = await camera.async_create_stream()
     if not stream:
         raise HomeAssistantError(
             f"{camera.entity_id} does not support play stream service"
@@ -937,7 +941,7 @@ async def async_handle_record_service(
     camera: Camera, service_call: ServiceCall
 ) -> None:
     """Handle stream recording service calls."""
-    stream = await camera.create_stream()
+    stream = await camera.async_create_stream()
 
     if not stream:
         raise HomeAssistantError(f"{camera.entity_id} does not support record service")

homeassistant/components/stream/__init__.py

@@ -424,11 +424,19 @@ class Stream:
             await hls.recv()
             recorder.prepend(list(hls.get_segments())[-num_segments:])
 
-    async def get_image(
+    async def async_get_image(
         self,
         width: int | None = None,
         height: int | None = None,
     ) -> bytes | None:
-        """Wrap get_image from KeyFrameConverter."""
+        """
+        Fetch an image from the Stream and return it as a jpeg in bytes.
 
-        return await self._keyframe_converter.get_image(width=width, height=height)
+        Calls async_get_image from KeyFrameConverter. async_get_image should only be
+        called directly from the main loop and not from an executor thread as it uses
+        hass.add_executor_job underneath the hood.
+        """
+
+        return await self._keyframe_converter.async_get_image(
+            width=width, height=height
+        )

homeassistant/components/stream/core.py

@@ -362,16 +362,16 @@ class StreamView(HomeAssistantView):
 
 class KeyFrameConverter:
     """
-    Generate and hold the keyframe as a jpeg.
+    Enables generating and getting an image from the last keyframe seen in the stream.
 
     An overview of the thread and state interaction:
         the worker thread sets a packet
-        at any time, main loop can run a get_image call
+        get_image is called from the main asyncio loop
+        get_image schedules _generate_image in an executor thread
         _generate_image will try to create an image from the packet
-            Running _generate_image will clear the packet, so there will only
-                be one attempt per packet
-            If successful, _image will be updated and returned by get_image
-            If unsuccessful, get_image will return the previous image
+        _generate_image will clear the packet, so there will only be one attempt per packet
+    If successful, self._image will be updated and returned by get_image
+    If unsuccessful, get_image will return the previous image
     """
 
     def __init__(self, hass: HomeAssistant) -> None:
@@ -430,7 +430,7 @@ class KeyFrameConverter:
             bgr_array = frame.to_ndarray(format="bgr24")
             self._image = bytes(self._turbojpeg.encode(bgr_array))
 
-    async def get_image(
+    async def async_get_image(
         self,
         width: int | None = None,
         height: int | None = None,

tests/components/stream/test_worker.py

@@ -892,6 +892,6 @@ async def test_get_image(hass, record_worker_sync):
 
     await record_worker_sync.join()
 
-    assert await stream.get_image() == EMPTY_8_6_JPEG
+    assert await stream.async_get_image() == EMPTY_8_6_JPEG
 
     stream.stop()