_start_trace() — langchain Function Reference

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

Function python Observability Tracers calls 1

Entity Profile

Observability→ Tracers→ _start_trace() — langchain Function Reference

Dependency Diagram

graph TD
  aa357f95_c4f3_1df6_b1f9_f92eda0e6da7["_start_trace()"]
  70348e44_de0f_ccb4_c06a_8453289ed93e["_TracerCore"]
  aa357f95_c4f3_1df6_b1f9_f92eda0e6da7 -->|defined in| 70348e44_de0f_ccb4_c06a_8453289ed93e
  5b191350_603e_2668_1158_5dd3352f7eea["_add_child_run()"]
  aa357f95_c4f3_1df6_b1f9_f92eda0e6da7 -->|calls| 5b191350_603e_2668_1158_5dd3352f7eea
  style aa357f95_c4f3_1df6_b1f9_f92eda0e6da7 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/langchain_core/tracers/core.py lines 108–130

    def _start_trace(self, run: Run) -> Coroutine[Any, Any, None] | None:  # type: ignore[return]
        current_dotted_order = run.start_time.strftime("%Y%m%dT%H%M%S%fZ") + str(run.id)
        if run.parent_run_id:
            if parent := self.order_map.get(run.parent_run_id):
                run.trace_id, run.dotted_order = parent
                run.dotted_order += "." + current_dotted_order
                if parent_run := self.run_map.get(str(run.parent_run_id)):
                    self._add_child_run(parent_run, run)
            else:
                if self.log_missing_parent:
                    logger.debug(
                        "Parent run %s not found for run %s. Treating as a root run.",
                        run.parent_run_id,
                        run.id,
                    )
                run.parent_run_id = None
                run.trace_id = run.id
                run.dotted_order = current_dotted_order
        else:
            run.trace_id = run.id
            run.dotted_order = current_dotted_order
        self.order_map[run.id] = (run.trace_id, run.dotted_order)
        self.run_map[str(run.id)] = run