Source code for langchain_core.tracers.root_listeners

from typing import Callable, Optional, Union
from uuid import UUID

from langchain_core.runnables.config import (
    RunnableConfig,
    call_func_with_variable_args,
)
from langchain_core.tracers.base import BaseTracer
from langchain_core.tracers.schemas import Run

Listener = Union[Callable[[Run], None], Callable[[Run, RunnableConfig], None]]


[docs]class RootListenersTracer(BaseTracer): """Tracer that calls listeners on run start, end, and error."""
[docs] def __init__( self, *, config: RunnableConfig, on_start: Optional[Listener], on_end: Optional[Listener], on_error: Optional[Listener], ) -> None: super().__init__() self.config = config self._arg_on_start = on_start self._arg_on_end = on_end self._arg_on_error = on_error self.root_id: Optional[UUID] = None
def _persist_run(self, run: Run) -> None: # This is a legacy method only called once for an entire run tree # therefore not useful here pass def _on_run_create(self, run: Run) -> None: if self.root_id is not None: return self.root_id = run.id if self._arg_on_start is not None: call_func_with_variable_args(self._arg_on_start, run, self.config) def _on_run_update(self, run: Run) -> None: if run.id != self.root_id: return if run.error is None: if self._arg_on_end is not None: call_func_with_variable_args(self._arg_on_end, run, self.config) else: if self._arg_on_error is not None: call_func_with_variable_args(self._arg_on_error, run, self.config)