with_listeners() — langchain Function Reference

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

Function python LangChainCore Runnables calls 1

Entity Profile

LangChainCore→ Runnables→ with_listeners() — langchain Function Reference

Dependency Diagram

graph TD
  6606ea6b_af21_fc53_21ca_cf61d28c7999["with_listeners()"]
  a94c7f6a_b072_1738_b1c2_2565e759189f["RunnableEach"]
  6606ea6b_af21_fc53_21ca_cf61d28c7999 -->|defined in| a94c7f6a_b072_1738_b1c2_2565e759189f
  c95b18f5_8485_9405_07af_f9e9f27e3fc6["with_listeners()"]
  6606ea6b_af21_fc53_21ca_cf61d28c7999 -->|calls| c95b18f5_8485_9405_07af_f9e9f27e3fc6
  style 6606ea6b_af21_fc53_21ca_cf61d28c7999 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/langchain_core/runnables/base.py lines 5459–5494

    def with_listeners(
        self,
        *,
        on_start: Callable[[Run], None]
        | Callable[[Run, RunnableConfig], None]
        | None = None,
        on_end: Callable[[Run], None]
        | Callable[[Run, RunnableConfig], None]
        | None = None,
        on_error: Callable[[Run], None]
        | Callable[[Run, RunnableConfig], None]
        | None = None,
    ) -> RunnableEach[Input, Output]:
        """Bind lifecycle listeners to a `Runnable`, returning a new `Runnable`.

        The `Run` object contains information about the run, including its `id`,
        `type`, `input`, `output`, `error`, `start_time`, `end_time`, and
        any tags or metadata added to the run.

        Args:
            on_start: Called before the `Runnable` starts running, with the `Run`
                object.
            on_end: Called after the `Runnable` finishes running, with the `Run`
                object.
            on_error: Called if the `Runnable` throws an error, with the `Run`
                object.

        Returns:
            A new `Runnable` with the listeners bound.

        """
        return RunnableEach(
            bound=self.bound.with_listeners(
                on_start=on_start, on_end=on_end, on_error=on_error
            )
        )