Merge pull request #3581 from BerriAI/litellm_log_metadata_langfuse_traces

[Feat] - log metadata on traces + allow users to log metadata when `existing_trace_id` exists

docs/my-website/docs/observability/langfuse_integration.md

@@ -136,6 +136,7 @@ response = completion(
       "existing_trace_id": "trace-id22",
       "trace_metadata": {"key": "updated_trace_value"},            # The new value to use for the langfuse Trace Metadata
       "update_trace_keys": ["input", "output", "trace_metadata"],  # Updates the trace input & output to be this generations input & output also updates the Trace Metadata to match the passed in value
+      "debug_langfuse": True,                                      # Will log the exact metadata sent to litellm for the trace/generation as `metadata_passed_to_litellm` 
   },
 )
 

litellm/integrations/langfuse.py

@@ -323,6 +323,7 @@ class LangFuseLogger:
             trace_id = clean_metadata.pop("trace_id", None)
             existing_trace_id = clean_metadata.pop("existing_trace_id", None)
             update_trace_keys = clean_metadata.pop("update_trace_keys", [])
+            debug = clean_metadata.pop("debug_langfuse", None)
 
             if trace_name is None and existing_trace_id is None:
                 # just log `litellm-{call_type}` as the trace name
@@ -376,6 +377,13 @@ class LangFuseLogger:
                 else:
                     trace_params["output"] = output
 
+            if debug == True or (isinstance(debug, str) and debug.lower() == "true"):
+                if "metadata" in trace_params:
+                    # log the raw_metadata in the trace
+                    trace_params["metadata"]["metadata_passed_to_litellm"] = metadata
+                else:
+                    trace_params["metadata"] = {"metadata_passed_to_litellm": metadata}
+
             cost = kwargs.get("response_cost", None)
             print_verbose(f"trace: {cost}")
 
@@ -426,7 +434,6 @@ class LangFuseLogger:
                     "url": url,
                     "headers": clean_headers,
                 }
-
             trace = self.Langfuse.trace(**trace_params)
 
             generation_id = None

litellm/tests/test_alangfuse.py

@@ -339,6 +339,13 @@ async def test_langfuse_logging_metadata(langfuse_client):
         for generation_id, generation in zip(generation_ids, generations):
             assert generation.id == generation_id
             assert generation.trace_id == trace_id
+            print(
+                "common keys in trace",
+                set(generation.metadata.keys()).intersection(
+                    expected_filtered_metadata_keys
+                ),
+            )
+
             assert set(generation.metadata.keys()).isdisjoint(
                 expected_filtered_metadata_keys
             )