fix(client): skip string serialization in attribute values (#1297)

* fix(client): skip string serialization in attribute values

* push

Author: hassiebp

langfuse/_client/attributes.py

@@ -152,7 +152,10 @@ def create_generation_attributes(
 
 
 def _serialize(obj: Any) -> Optional[str]:
-    return json.dumps(obj, cls=EventSerializer) if obj is not None else None
+    if obj is None or isinstance(obj, str):
+        return obj
+
+    return json.dumps(obj, cls=EventSerializer)
 
 
 def _flatten_and_serialize_metadata(

tests/test_decorators.py

@@ -905,7 +905,7 @@ async def level_1_function(*args, **kwargs):
     assert generation.usage.output is not None
     assert generation.usage.total is not None
     print(generation)
-    assert generation.output == "2"
+    assert generation.output == 2
 
 
 def test_generator_as_function_input():

tests/test_openai.py

@@ -119,7 +119,7 @@ def test_openai_chat_completion_stream(openai):
     assert generation.data[0].usage.input is not None
     assert generation.data[0].usage.output is not None
     assert generation.data[0].usage.total is not None
-    assert generation.data[0].output == "2"
+    assert generation.data[0].output == 2
     assert generation.data[0].completion_start_time is not None
 
     # Completion start time for time-to-first-token
@@ -179,7 +179,7 @@ def test_openai_chat_completion_stream_with_next_iteration(openai):
     assert generation.data[0].usage.input is not None
     assert generation.data[0].usage.output is not None
     assert generation.data[0].usage.total is not None
-    assert generation.data[0].output == "2"
+    assert generation.data[0].output == 2
     assert generation.data[0].completion_start_time is not None
 
     # Completion start time for time-to-first-token