context.py — langchain Source File

Source Code

"""Context management for tracers."""

from __future__ import annotations

from contextlib import contextmanager
from contextvars import ContextVar
from typing import (
    TYPE_CHECKING,
    Any,
    Literal,
    cast,
)
from uuid import UUID

from langsmith import run_helpers as ls_rh
from langsmith import utils as ls_utils

from langchain_core.tracers.langchain import LangChainTracer
from langchain_core.tracers.run_collector import RunCollectorCallbackHandler

if TYPE_CHECKING:
    from collections.abc import Generator

    from langsmith import Client as LangSmithClient

    from langchain_core.callbacks.base import BaseCallbackHandler, Callbacks
    from langchain_core.callbacks.manager import AsyncCallbackManager, CallbackManager

# for backwards partial compatibility if this is imported by users but unused
tracing_callback_var: Any = None
tracing_v2_callback_var: ContextVar[LangChainTracer | None] = ContextVar(
    "tracing_callback_v2", default=None
)
run_collector_var: ContextVar[RunCollectorCallbackHandler | None] = ContextVar(
    "run_collector", default=None
)


@contextmanager
def tracing_v2_enabled(
    project_name: str | None = None,
    *,
    example_id: str | UUID | None = None,
    tags: list[str] | None = None,
    client: LangSmithClient | None = None,
) -> Generator[LangChainTracer, None, None]:
    """Instruct LangChain to log all runs in context to LangSmith.

    Args:
        project_name: The name of the project.

            Defaults to `'default'`.
        example_id: The ID of the example.
        tags: The tags to add to the run.
        client: The client of the langsmith.

    Yields:
        The LangChain tracer.

    Example:
// ... (146 more lines)