on_chain_start() — langchain Function Reference

Architecture documentation for the on_chain_start() function in file.py from the langchain codebase.

Function python Observability TelemetryUtilities calls 1

Entity Profile

Observability→ TelemetryUtilities→ on_chain_start() — langchain Function Reference

Dependency Diagram

graph TD
  b49e271b_5ffb_4c0a_2546_acb41b8cc221["on_chain_start()"]
  52737fd4_dd58_4289_8b70_0131f09b23a5["FileCallbackHandler"]
  b49e271b_5ffb_4c0a_2546_acb41b8cc221 -->|defined in| 52737fd4_dd58_4289_8b70_0131f09b23a5
  efeb47b6_76c6_8f45_76b9_d26fbc90c538["_write()"]
  b49e271b_5ffb_4c0a_2546_acb41b8cc221 -->|calls| efeb47b6_76c6_8f45_76b9_d26fbc90c538
  style b49e271b_5ffb_4c0a_2546_acb41b8cc221 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/langchain_core/callbacks/file.py lines 164–180

    def on_chain_start(
        self, serialized: dict[str, Any], inputs: dict[str, Any], **kwargs: Any
    ) -> None:
        """Print that we are entering a chain.

        Args:
            serialized: The serialized chain information.
            inputs: The inputs to the chain.
            **kwargs: Additional keyword arguments that may contain `'name'`.

        """
        name = (
            kwargs.get("name")
            or serialized.get("name", serialized.get("id", ["<unknown>"])[-1])
            or "<unknown>"
        )
        self._write(f"\n\n> Entering new {name} chain...", end="\n")