docs/langchain/libs/community/langchain_community/callbacks/manager.py

from __future__ import annotations

import logging
from contextlib import contextmanager
from contextvars import ContextVar
from typing import (
    Generator,
    Optional,
)

from langchain_core.tracers.context import register_configure_hook

from langchain_community.callbacks.bedrock_anthropic_callback import (
    BedrockAnthropicTokenUsageCallbackHandler,
)
from langchain_community.callbacks.openai_info import OpenAICallbackHandler
from langchain_community.callbacks.tracers.comet import CometTracer
from langchain_community.callbacks.tracers.wandb import WandbTracer

logger = logging.getLogger(__name__)

openai_callback_var: ContextVar[Optional[OpenAICallbackHandler]] = ContextVar(
    "openai_callback", default=None
)
bedrock_anthropic_callback_var: (ContextVar)[
    Optional[BedrockAnthropicTokenUsageCallbackHandler]
] = ContextVar("bedrock_anthropic_callback", default=None)
wandb_tracing_callback_var: ContextVar[Optional[WandbTracer]] = ContextVar(
    "tracing_wandb_callback", default=None
)
comet_tracing_callback_var: ContextVar[Optional[CometTracer]] = ContextVar(
    "tracing_comet_callback", default=None
)

register_configure_hook(openai_callback_var, True)
register_configure_hook(bedrock_anthropic_callback_var, True)
register_configure_hook(
    wandb_tracing_callback_var, True, WandbTracer, "LANGCHAIN_WANDB_TRACING"
)
register_configure_hook(
    comet_tracing_callback_var, True, CometTracer, "LANGCHAIN_COMET_TRACING"
)


@contextmanager
def get_openai_callback() -> Generator[OpenAICallbackHandler, None, None]:
    """Get the OpenAI callback handler in a context manager.
    which conveniently exposes token and cost information.

    Returns:
        OpenAICallbackHandler: The OpenAI callback handler.

    Example:
        >>> with get_openai_callback() as cb:
        ...     # Use the OpenAI callback handler
    """
    cb = OpenAICallbackHandler()
    openai_callback_var.set(cb)
    yield cb
    openai_callback_var.set(None)


@contextmanager
def get_bedrock_anthropic_callback() -> (
    Generator[BedrockAnthropicTokenUsageCallbackHandler, None, None]
):
    """Get the Bedrock anthropic callback handler in a context manager.
    which conveniently exposes token and cost information.

    Returns:
        BedrockAnthropicTokenUsageCallbackHandler:
            The Bedrock anthropic callback handler.

    Example:
        >>> with get_bedrock_anthropic_callback() as cb:
        ...     # Use the Bedrock anthropic callback handler
    """
    cb = BedrockAnthropicTokenUsageCallbackHandler()
    bedrock_anthropic_callback_var.set(cb)
    yield cb
    bedrock_anthropic_callback_var.set(None)


@contextmanager
def wandb_tracing_enabled(
    session_name: str = "default",
) -> Generator[None, None, None]:
    """Get the WandbTracer in a context manager.

    Args:
        session_name (str, optional): The name of the session.
            Defaults to "default".

    Returns:
        None

    Example:
        >>> with wandb_tracing_enabled() as session:
        ...     # Use the WandbTracer session
    """
    cb = WandbTracer()
    wandb_tracing_callback_var.set(cb)
    yield None
    wandb_tracing_callback_var.set(None)