Source code for langchain_core.callbacks.base

"""Base callback handler that can be used to handle callbacks in langchain."""
from __future__ import annotations

from typing import TYPE_CHECKING, Any, Dict, List, Optional, Sequence, TypeVar, Union
from uuid import UUID

from tenacity import RetryCallState

if TYPE_CHECKING:
    from langchain_core.agents import AgentAction, AgentFinish
    from langchain_core.documents import Document
    from langchain_core.messages import BaseMessage
    from langchain_core.outputs import ChatGenerationChunk, GenerationChunk, LLMResult


class RetrieverManagerMixin:
    """Mixin for Retriever callbacks."""

    def on_retriever_error(
        self,
        error: BaseException,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        **kwargs: Any,
    ) -> Any:
        """Run when Retriever errors."""

    def on_retriever_end(
        self,
        documents: Sequence[Document],
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        **kwargs: Any,
    ) -> Any:
        """Run when Retriever ends running."""


class LLMManagerMixin:
    """Mixin for LLM callbacks."""

    def on_llm_new_token(
        self,
        token: str,
        *,
        chunk: Optional[Union[GenerationChunk, ChatGenerationChunk]] = None,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        **kwargs: Any,
    ) -> Any:
        """Run on new LLM token. Only available when streaming is enabled.

        Args:
            token (str): The new token.
            chunk (GenerationChunk | ChatGenerationChunk): The new generated chunk,
            containing content and other information.
        """

    def on_llm_end(
        self,
        response: LLMResult,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        **kwargs: Any,
    ) -> Any:
        """Run when LLM ends running."""

    def on_llm_error(
        self,
        error: BaseException,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        **kwargs: Any,
    ) -> Any:
        """Run when LLM errors.
        Args:
            error (BaseException): The error that occurred.
            kwargs (Any): Additional keyword arguments.
                - response (LLMResult): The response which was generated before
                    the error occurred.
        """


class ChainManagerMixin:
    """Mixin for chain callbacks."""

    def on_chain_end(
        self,
        outputs: Dict[str, Any],
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        **kwargs: Any,
    ) -> Any:
        """Run when chain ends running."""

    def on_chain_error(
        self,
        error: BaseException,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        **kwargs: Any,
    ) -> Any:
        """Run when chain errors."""

    def on_agent_action(
        self,
        action: AgentAction,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        **kwargs: Any,
    ) -> Any:
        """Run on agent action."""

    def on_agent_finish(
        self,
        finish: AgentFinish,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        **kwargs: Any,
    ) -> Any:
        """Run on agent end."""


class ToolManagerMixin:
    """Mixin for tool callbacks."""

    def on_tool_end(
        self,
        output: Any,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        **kwargs: Any,
    ) -> Any:
        """Run when tool ends running."""

    def on_tool_error(
        self,
        error: BaseException,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        **kwargs: Any,
    ) -> Any:
        """Run when tool errors."""


class CallbackManagerMixin:
    """Mixin for callback manager."""

    def on_llm_start(
        self,
        serialized: Dict[str, Any],
        prompts: List[str],
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        metadata: Optional[Dict[str, Any]] = None,
        **kwargs: Any,
    ) -> Any:
        """Run when LLM starts running.

        **ATTENTION**: This method is called for non-chat models (regular LLMs). If
            you're implementing a handler for a chat model,
            you should use on_chat_model_start instead.
        """

    def on_chat_model_start(
        self,
        serialized: Dict[str, Any],
        messages: List[List[BaseMessage]],
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        metadata: Optional[Dict[str, Any]] = None,
        **kwargs: Any,
    ) -> Any:
        """Run when a chat model starts running.

        **ATTENTION**: This method is called for chat models. If you're implementing
            a handler for a non-chat model, you should use on_llm_start instead.
        """
        # NotImplementedError is thrown intentionally
        # Callback handler will fall back to on_llm_start if this is exception is thrown
        raise NotImplementedError(
            f"{self.__class__.__name__} does not implement `on_chat_model_start`"
        )

    def on_retriever_start(
        self,
        serialized: Dict[str, Any],
        query: str,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        metadata: Optional[Dict[str, Any]] = None,
        **kwargs: Any,
    ) -> Any:
        """Run when Retriever starts running."""

    def on_chain_start(
        self,
        serialized: Dict[str, Any],
        inputs: Dict[str, Any],
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        metadata: Optional[Dict[str, Any]] = None,
        **kwargs: Any,
    ) -> Any:
        """Run when chain starts running."""

    def on_tool_start(
        self,
        serialized: Dict[str, Any],
        input_str: str,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        metadata: Optional[Dict[str, Any]] = None,
        inputs: Optional[Dict[str, Any]] = None,
        **kwargs: Any,
    ) -> Any:
        """Run when tool starts running."""


class RunManagerMixin:
    """Mixin for run manager."""

    def on_text(
        self,
        text: str,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        **kwargs: Any,
    ) -> Any:
        """Run on arbitrary text."""

    def on_retry(
        self,
        retry_state: RetryCallState,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        **kwargs: Any,
    ) -> Any:
        """Run on a retry event."""


class BaseCallbackHandler(
    LLMManagerMixin,
    ChainManagerMixin,
    ToolManagerMixin,
    RetrieverManagerMixin,
    CallbackManagerMixin,
    RunManagerMixin,
):
    """Base callback handler that handles callbacks from LangChain."""

    raise_error: bool = False

    run_inline: bool = False

    @property
    def ignore_llm(self) -> bool:
        """Whether to ignore LLM callbacks."""
        return False

    @property
    def ignore_retry(self) -> bool:
        """Whether to ignore retry callbacks."""
        return False

    @property
    def ignore_chain(self) -> bool:
        """Whether to ignore chain callbacks."""
        return False

    @property
    def ignore_agent(self) -> bool:
        """Whether to ignore agent callbacks."""
        return False

    @property
    def ignore_retriever(self) -> bool:
        """Whether to ignore retriever callbacks."""
        return False

    @property
    def ignore_chat_model(self) -> bool:
        """Whether to ignore chat model callbacks."""
        return False


class AsyncCallbackHandler(BaseCallbackHandler):
    """Async callback handler that handles callbacks from LangChain."""

    async def on_llm_start(
        self,
        serialized: Dict[str, Any],
        prompts: List[str],
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        metadata: Optional[Dict[str, Any]] = None,
        **kwargs: Any,
    ) -> None:
        """Run when LLM starts running.

        **ATTENTION**: This method is called for non-chat models (regular LLMs). If
            you're implementing a handler for a chat model,
            you should use on_chat_model_start instead.
        """

    async def on_chat_model_start(
        self,
        serialized: Dict[str, Any],
        messages: List[List[BaseMessage]],
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        metadata: Optional[Dict[str, Any]] = None,
        **kwargs: Any,
    ) -> Any:
        """Run when a chat model starts running.

        **ATTENTION**: This method is called for chat models. If you're implementing
            a handler for a non-chat model, you should use on_llm_start instead.
        """
        # NotImplementedError is thrown intentionally
        # Callback handler will fall back to on_llm_start if this is exception is thrown
        raise NotImplementedError(
            f"{self.__class__.__name__} does not implement `on_chat_model_start`"
        )

    async def on_llm_new_token(
        self,
        token: str,
        *,
        chunk: Optional[Union[GenerationChunk, ChatGenerationChunk]] = None,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        **kwargs: Any,
    ) -> None:
        """Run on new LLM token. Only available when streaming is enabled."""

    async def on_llm_end(
        self,
        response: LLMResult,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        **kwargs: Any,
    ) -> None:
        """Run when LLM ends running."""

    async def on_llm_error(
        self,
        error: BaseException,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        **kwargs: Any,
    ) -> None:
        """Run when LLM errors.

        Args:
            error: The error that occurred.
            kwargs (Any): Additional keyword arguments.
                - response (LLMResult): The response which was generated before
                    the error occurred.
        """

    async def on_chain_start(
        self,
        serialized: Dict[str, Any],
        inputs: Dict[str, Any],
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        metadata: Optional[Dict[str, Any]] = None,
        **kwargs: Any,
    ) -> None:
        """Run when chain starts running."""

    async def on_chain_end(
        self,
        outputs: Dict[str, Any],
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        **kwargs: Any,
    ) -> None:
        """Run when chain ends running."""

    async def on_chain_error(
        self,
        error: BaseException,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        **kwargs: Any,
    ) -> None:
        """Run when chain errors."""

    async def on_tool_start(
        self,
        serialized: Dict[str, Any],
        input_str: str,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        metadata: Optional[Dict[str, Any]] = None,
        inputs: Optional[Dict[str, Any]] = None,
        **kwargs: Any,
    ) -> None:
        """Run when tool starts running."""

    async def on_tool_end(
        self,
        output: Any,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        **kwargs: Any,
    ) -> None:
        """Run when tool ends running."""

    async def on_tool_error(
        self,
        error: BaseException,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        **kwargs: Any,
    ) -> None:
        """Run when tool errors."""

    async def on_text(
        self,
        text: str,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        **kwargs: Any,
    ) -> None:
        """Run on arbitrary text."""

    async def on_retry(
        self,
        retry_state: RetryCallState,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        **kwargs: Any,
    ) -> Any:
        """Run on a retry event."""

    async def on_agent_action(
        self,
        action: AgentAction,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        **kwargs: Any,
    ) -> None:
        """Run on agent action."""

    async def on_agent_finish(
        self,
        finish: AgentFinish,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        **kwargs: Any,
    ) -> None:
        """Run on agent end."""

    async def on_retriever_start(
        self,
        serialized: Dict[str, Any],
        query: str,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        metadata: Optional[Dict[str, Any]] = None,
        **kwargs: Any,
    ) -> None:
        """Run on retriever start."""

    async def on_retriever_end(
        self,
        documents: Sequence[Document],
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        **kwargs: Any,
    ) -> None:
        """Run on retriever end."""

    async def on_retriever_error(
        self,
        error: BaseException,
        *,
        run_id: UUID,
        parent_run_id: Optional[UUID] = None,
        tags: Optional[List[str]] = None,
        **kwargs: Any,
    ) -> None:
        """Run on retriever error."""


T = TypeVar("T", bound="BaseCallbackManager")


class BaseCallbackManager(CallbackManagerMixin):
    """Base callback manager that handles callbacks from LangChain."""

    def __init__(
        self,
        handlers: List[BaseCallbackHandler],
        inheritable_handlers: Optional[List[BaseCallbackHandler]] = None,
        parent_run_id: Optional[UUID] = None,
        *,
        tags: Optional[List[str]] = None,
        inheritable_tags: Optional[List[str]] = None,
        metadata: Optional[Dict[str, Any]] = None,
        inheritable_metadata: Optional[Dict[str, Any]] = None,
    ) -> None:
        """Initialize callback manager."""
        self.handlers: List[BaseCallbackHandler] = handlers
        self.inheritable_handlers: List[BaseCallbackHandler] = (
            inheritable_handlers or []
        )
        self.parent_run_id: Optional[UUID] = parent_run_id
        self.tags = tags or []
        self.inheritable_tags = inheritable_tags or []
        self.metadata = metadata or {}
        self.inheritable_metadata = inheritable_metadata or {}

    def copy(self: T) -> T:
        """Copy the callback manager."""
        return self.__class__(
            handlers=self.handlers,
            inheritable_handlers=self.inheritable_handlers,
            parent_run_id=self.parent_run_id,
            tags=self.tags,
            inheritable_tags=self.inheritable_tags,
            metadata=self.metadata,
            inheritable_metadata=self.inheritable_metadata,
        )

    @property
    def is_async(self) -> bool:
        """Whether the callback manager is async."""
        return False

    def add_handler(self, handler: BaseCallbackHandler, inherit: bool = True) -> None:
        """Add a handler to the callback manager."""
        if handler not in self.handlers:
            self.handlers.append(handler)
        if inherit and handler not in self.inheritable_handlers:
            self.inheritable_handlers.append(handler)

    def remove_handler(self, handler: BaseCallbackHandler) -> None:
        """Remove a handler from the callback manager."""
        self.handlers.remove(handler)
        self.inheritable_handlers.remove(handler)

    def set_handlers(
        self, handlers: List[BaseCallbackHandler], inherit: bool = True
    ) -> None:
        """Set handlers as the only handlers on the callback manager."""
        self.handlers = []
        self.inheritable_handlers = []
        for handler in handlers:
            self.add_handler(handler, inherit=inherit)

    def set_handler(self, handler: BaseCallbackHandler, inherit: bool = True) -> None:
        """Set handler as the only handler on the callback manager."""
        self.set_handlers([handler], inherit=inherit)

    def add_tags(self, tags: List[str], inherit: bool = True) -> None:
        for tag in tags:
            if tag in self.tags:
                self.remove_tags([tag])
        self.tags.extend(tags)
        if inherit:
            self.inheritable_tags.extend(tags)

    def remove_tags(self, tags: List[str]) -> None:
        for tag in tags:
            self.tags.remove(tag)
            self.inheritable_tags.remove(tag)

    def add_metadata(self, metadata: Dict[str, Any], inherit: bool = True) -> None:
        self.metadata.update(metadata)
        if inherit:
            self.inheritable_metadata.update(metadata)

    def remove_metadata(self, keys: List[str]) -> None:
        for key in keys:
            self.metadata.pop(key)
            self.inheritable_metadata.pop(key)


Callbacks = Optional[Union[List[BaseCallbackHandler], BaseCallbackManager]]