refac: otel metrics handle 500

backend/open_webui/utils/telemetry/metrics.py

@@ -163,7 +163,16 @@ def setup_metrics(app: FastAPI, resource: Resource) -> None:
     @app.middleware("http")
     async def _metrics_middleware(request: Request, call_next):
         start_time = time.perf_counter()
+
+        status_code = None
+        try:
             response = await call_next(request)
+            status_code = getattr(response, "status_code", 500)
+            return response
+        except Exception:
+            status_code = 500
+            raise
+        finally:
             elapsed_ms = (time.perf_counter() - start_time) * 1000.0
 
             # Route template e.g. "/items/{item_id}" instead of real path.
@@ -173,10 +182,8 @@ def setup_metrics(app: FastAPI, resource: Resource) -> None:
             attrs: Dict[str, str | int] = {
                 "http.method": request.method,
                 "http.route": route_path,
-            "http.status_code": response.status_code,
+                "http.status_code": status_code,
             }
 
             request_counter.add(1, attrs)
             duration_histogram.record(elapsed_ms, attrs)
-
-        return response