on_chain_end() — langchain Function Reference

Architecture documentation for the on_chain_end() function in event_stream.py from the langchain codebase.

Function python Observability Tracers calls 2

Entity Profile

Observability→ Tracers→ on_chain_end() — langchain Function Reference

Dependency Diagram

graph TD
  d38cbd4d_fc35_d53c_9d4f_e6a10db4ea23["on_chain_end()"]
  33d093c4_1ed0_fc6a_17c6_762d4c5cfa04["_AstreamEventsCallbackHandler"]
  d38cbd4d_fc35_d53c_9d4f_e6a10db4ea23 -->|defined in| 33d093c4_1ed0_fc6a_17c6_762d4c5cfa04
  87f79bee_f9c5_8262_1829_62f633c4f870["_send()"]
  d38cbd4d_fc35_d53c_9d4f_e6a10db4ea23 -->|calls| 87f79bee_f9c5_8262_1829_62f633c4f870
  9aed8e4f_9d4c_016f_aa43_c5908015cf8d["_get_parent_ids()"]
  d38cbd4d_fc35_d53c_9d4f_e6a10db4ea23 -->|calls| 9aed8e4f_9d4c_016f_aa43_c5908015cf8d
  style d38cbd4d_fc35_d53c_9d4f_e6a10db4ea23 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/langchain_core/tracers/event_stream.py lines 598–630

    async def on_chain_end(
        self,
        outputs: dict[str, Any],
        *,
        run_id: UUID,
        inputs: dict[str, Any] | None = None,
        **kwargs: Any,
    ) -> None:
        """End a trace for a chain run."""
        run_info = self.run_map.pop(run_id)
        run_type = run_info["run_type"]

        event = f"on_{run_type}_end"

        inputs = inputs or run_info.get("inputs") or {}

        data: EventData = {
            "output": outputs,
            "input": inputs,
        }

        self._send(
            {
                "event": event,
                "data": data,
                "run_id": str(run_id),
                "name": run_info["name"],
                "tags": run_info["tags"],
                "metadata": run_info["metadata"],
                "parent_ids": self._get_parent_ids(run_id),
            },
            run_type,
        )