Update rag_retrieval.py

rag_retrieval.py

@@ -275,4 +275,6 @@ def log_trace(session_id: str, user_text: str, rewrite: str, retrieved, answer,
     }
 
     with trace_path.open("a", encoding="utf-8") as f:
-        f.write(json.dumps(record) + "\n")
+        f.write(json.dumps(record) + "\n")
+
+    return record["trace_id"]