_on_retriever_start() — langchain Function Reference

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

Function python Observability Tracers calls 1

Entity Profile

Observability→ Tracers→ _on_retriever_start() — langchain Function Reference

Dependency Diagram

graph TD
  d17d790f_24b9_b1a6_f604_2cfa093ab528["_on_retriever_start()"]
  178590bb_85ff_b79e_979a_46e5c3c5389f["LangChainTracer"]
  d17d790f_24b9_b1a6_f604_2cfa093ab528 -->|defined in| 178590bb_85ff_b79e_979a_46e5c3c5389f
  cf43defe_cb35_deb4_9782_55f973cdf6ca["_persist_run_single()"]
  d17d790f_24b9_b1a6_f604_2cfa093ab528 -->|calls| cf43defe_cb35_deb4_9782_55f973cdf6ca
  style d17d790f_24b9_b1a6_f604_2cfa093ab528 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/langchain_core/tracers/langchain.py lines 360–364

    def _on_retriever_start(self, run: Run) -> None:
        """Process the Retriever Run upon start."""
        if run.parent_run_id is None:
            run.reference_example_id = self.example_id
        self._persist_run_single(run)