Fixed a race condition in FastAPIWebsocketClient that occurred when attempting to send a message while the client was disconnecting.

CHANGELOG.md

@@ -97,6 +97,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- Fixed a race condition in `FastAPIWebsocketClient` that occurred when attempting to
+  send a message while the client was disconnecting.
+
 - Fixed an issue in `GoogleLLMService` where interruptions did not work when an
   interruption strategy was used.
 

src/pipecat/transports/network/fastapi_websocket.py

@@ -132,8 +132,11 @@ class FastAPIWebsocketClient:
                 f"{self} exception sending data: {e.__class__.__name__} ({e}), application_state: {self._websocket.application_state}"
             )
             # For some reason the websocket is disconnected, and we are not able to send data
-            # So let's properly handle it and disconnect the transport
-            if self._websocket.application_state == WebSocketState.DISCONNECTED:
+            # So let's properly handle it and disconnect the transport if it is not already disconnecting
+            if (
+                self._websocket.application_state == WebSocketState.DISCONNECTED
+                and not self.is_closing
+            ):
                 logger.warning("Closing already disconnected websocket!")
                 self._closing = True
                 await self.trigger_client_disconnected()
@@ -146,8 +149,12 @@ class FastAPIWebsocketClient:
 
         if self.is_connected and not self.is_closing:
             self._closing = True
-            await self._websocket.close()
-            await self.trigger_client_disconnected()
+            try:
+                await self._websocket.close()
+            except Exception as e:
+                logger.error(f"{self} exception while closing the websocket: {e}")
+            finally:
+                await self.trigger_client_disconnected()
 
     async def trigger_client_disconnected(self):
         """Trigger the client disconnected callback."""