feat: log provider errors to console for better insights (open-webui#23379)

* fix: log provider errors that were silently swallowed

* Update main.py

* fix: wrap non-JSON SSE error responses in JSON so middleware handles them

Author: Classic298

backend/open_webui/main.py

@@ -1797,7 +1797,7 @@ async def process_chat(request, form_data, user, metadata, model):
             finally:
                 raise  # re-raise to ensure proper task cancellation handling
         except Exception as e:
-            log.debug(f'Error processing chat payload: {e}')
+            log.error('Error processing chat payload: %s', e)
             if metadata.get('chat_id') and metadata.get('message_id'):
                 # Update the chat message with the error
                 try:

backend/open_webui/routers/openai.py

@@ -1195,6 +1195,25 @@ async def generate_chat_completion(
 
         # Check if response is SSE
         if 'text/event-stream' in r.headers.get('Content-Type', ''):
+            # If the provider returned an error status with SSE content-type,
+            # read the body and return a proper error response instead of
+            # streaming the error back (which hides the error from logs).
+            if r.status >= 400:
+                error_body = await r.text()
+                log.error(
+                    'Provider returned HTTP %d with SSE content-type: %s',
+                    r.status,
+                    error_body[:1000],
+                )
+                try:
+                    error_json = json.loads(error_body)
+                    return JSONResponse(status_code=r.status, content=error_json)
+                except json.JSONDecodeError:
+                    return JSONResponse(
+                        status_code=r.status,
+                        content={"error": {"message": error_body, "code": r.status}},
+                    )
+
             streaming = True
             return StreamingResponse(
                 stream_wrapper(r, content_handler=stream_chunks_handler),

backend/open_webui/utils/middleware.py

@@ -3077,6 +3077,8 @@ async def non_streaming_chat_response_handler(response, ctx):
                 else:
                     error = str(error)
 
+                log.error('Provider returned error (non-streaming): %s', error)
+
                 await Chats.upsert_message_to_chat_by_id_and_message_id(
                     metadata['chat_id'],
                     metadata['message_id'],
@@ -3645,6 +3647,7 @@ async def flush_pending_delta_data(threshold: int = 0):
                                     if not choices:
                                         error = data.get('error', {})
                                         if error:
+                                            log.error('Provider returned error (streaming): %s', error)
                                             try:
                                                 await Chats.upsert_message_to_chat_by_id_and_message_id(
                                                     metadata['chat_id'],