close ws channel if can't accept

freqtrade/rpc/api_server/ws/channel.py

@@ -125,9 +125,14 @@ class WebSocketChannel:
 
     async def accept(self):
         """
-        Accept the underlying websocket connection
+        Accept the underlying websocket connection,
+        if the connection has been closed before we can
+        accept, just close the channel.
         """
-        return await self._websocket.accept()
+        try:
+            return await self._websocket.accept()
+        except RuntimeError:
+            await self.close()
 
     async def close(self):
         """
@@ -172,17 +177,18 @@ class WebSocketChannel:
         :param **kwargs: Any extra kwargs to pass to gather
         """
 
-        # Wrap the coros into tasks if they aren't already
-        self._channel_tasks = [
-            task if isinstance(task, asyncio.Task) else asyncio.create_task(task)
-            for task in tasks
-        ]
+        if not self.is_closed():
+            # Wrap the coros into tasks if they aren't already
+            self._channel_tasks = [
+                task if isinstance(task, asyncio.Task) else asyncio.create_task(task)
+                for task in tasks
+            ]
 
-        try:
-            return await asyncio.gather(*self._channel_tasks, **kwargs)
-        except Exception:
-            # If an exception occurred, cancel the rest of the tasks
-            await self.cancel_channel_tasks()
+            try:
+                return await asyncio.gather(*self._channel_tasks, **kwargs)
+            except Exception:
+                # If an exception occurred, cancel the rest of the tasks
+                await self.cancel_channel_tasks()
 
     async def cancel_channel_tasks(self):
         """
@@ -191,19 +197,19 @@ class WebSocketChannel:
         for task in self._channel_tasks:
             task.cancel()
 
-        # Wait for tasks to finish cancelling
-        try:
-            await task
-        except (
-            asyncio.CancelledError,
-            asyncio.TimeoutError,
-            WebSocketDisconnect,
-            ConnectionClosed,
-            RuntimeError
-        ):
-            pass
-        except Exception as e:
-            logger.info(f"Encountered unknown exception: {e}", exc_info=e)
+            # Wait for tasks to finish cancelling
+            try:
+                await task
+            except (
+                asyncio.CancelledError,
+                asyncio.TimeoutError,
+                WebSocketDisconnect,
+                ConnectionClosed,
+                RuntimeError
+            ):
+                pass
+            except Exception as e:
+                logger.info(f"Encountered unknown exception: {e}", exc_info=e)
 
         self._channel_tasks = []