Method on_chain_start

libs/core/langchain_core/tracers/base.py:172–199

Start a trace for a chain run.

(
        self,
        serialized: Dict[str, Any],
        inputs: Dict[str, Any],
        *,
        run_id: UUID,
        tags: Optional[List[str]] = None,
        parent_run_id: Optional[UUID] = None,
        metadata: Optional[Dict[str, Any]] = None,
        run_type: Optional[str] = None,
        name: Optional[str] = None,
        **kwargs: Any,
    )

        return llm_run

    def on_chain_start(
        self,
        serialized: Dict[str, Any],
        inputs: Dict[str, Any],
        *,
        run_id: UUID,
        tags: Optional[List[str]] = None,
        parent_run_id: Optional[UUID] = None,
        metadata: Optional[Dict[str, Any]] = None,
        run_type: Optional[str] = None,
        name: Optional[str] = None,
        **kwargs: Any,
    ) -> Run:
        """Start a trace for a chain run."""
        chain_run = self._create_chain_run(
            serialized=serialized,
            inputs=inputs,
            run_id=run_id,
            tags=tags,
            parent_run_id=parent_run_id,
            metadata=metadata,
            run_type=run_type,
            name=name,
            **kwargs,
        )
        self._start_trace(chain_run)
        self._on_chain_start(chain_run)
        return chain_run

    def on_chain_end(
        self,