debug: find reason of 500 error during promisc

Signed-off-by: Denys Fedoryshchenko <denys.f@collabora.com>

Author: nuclearcat

api/main.py

@@ -1412,7 +1412,13 @@ async def listen(sub_id: int, user: User = Depends(get_current_user)):
     """Listen messages from a subscribed Pub/Sub channel"""
     metrics.add('http_requests_total', 1)
     try:
-        return await pubsub.listen(sub_id, user.username)
+        result = await pubsub.listen(sub_id, user.username)
+        # Debug: print result type and check for bytes
+        print(f"[DEBUG listen] result type: {type(result)}")
+        if result:
+            for k, v in result.items():
+                print(f"[DEBUG listen] {k}: {type(v)} = {repr(v)[:100]}")
+        return result
     except KeyError as error:
         raise HTTPException(
             status_code=status.HTTP_404_NOT_FOUND,
@@ -1423,6 +1429,10 @@ async def listen(sub_id: int, user: User = Depends(get_current_user)):
             status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
             detail=f"Error while listening to sub id {sub_id}: {str(error)}"
         ) from error
+    except Exception as error:
+        print(f"[DEBUG listen] Unexpected error: {type(error).__name__}: {error}")
+        traceback.print_exc()
+        raise
 
 
 @app.post('/publish/{channel}')