langchain/tests/unit_tests/callbacks/fake_callback_handler.py

"""A fake callback handler for testing purposes."""
from typing import Any

from pydantic import BaseModel

from langchain.callbacks.base import AsyncCallbackHandler, BaseCallbackHandler


class BaseFakeCallbackHandler(BaseModel):
    """Base fake callback handler for testing."""

    starts: int = 0
    ends: int = 0
    errors: int = 0
    text: int = 0
    ignore_llm_: bool = False
    ignore_chain_: bool = False
    ignore_agent_: bool = False

    # add finer-grained counters for easier debugging of failing tests
    chain_starts: int = 0
    chain_ends: int = 0
    llm_starts: int = 0
    llm_ends: int = 0
    llm_streams: int = 0
    tool_starts: int = 0
    tool_ends: int = 0
    agent_actions: int = 0
    agent_ends: int = 0


class BaseFakeCallbackHandlerMixin(BaseFakeCallbackHandler):
    """Base fake callback handler mixin for testing."""

    def on_llm_start_common(self) -> None:
        self.llm_starts += 1
        self.starts += 1

    def on_llm_end_common(self) -> None:
        self.llm_ends += 1
        self.ends += 1

    def on_llm_error_common(self) -> None:
        self.errors += 1

    def on_llm_new_token_common(self) -> None:
        self.llm_streams += 1

    def on_chain_start_common(self) -> None:
        self.chain_starts += 1
        self.starts += 1

    def on_chain_end_common(self) -> None:
        self.chain_ends += 1
        self.ends += 1

    def on_chain_error_common(self) -> None:
        self.errors += 1

    def on_tool_start_common(self) -> None:
        self.tool_starts += 1
        self.starts += 1

    def on_tool_end_common(self) -> None:
        self.tool_ends += 1
        self.ends += 1

    def on_tool_error_common(self) -> None:
        self.errors += 1

    def on_agent_action_common(self) -> None:
        self.agent_actions += 1
        self.starts += 1

    def on_agent_finish_common(self) -> None:
        self.agent_ends += 1
        self.ends += 1

    def on_text_common(self) -> None:
        self.text += 1


class FakeCallbackHandler(BaseCallbackHandler, BaseFakeCallbackHandlerMixin):
    """Fake callback handler for testing."""

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

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

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

    def on_llm_start(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> Any:
        self.on_llm_start_common()

    def on_llm_new_token(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> Any:
        self.on_llm_new_token_common()

    def on_llm_end(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> Any:
        self.on_llm_end_common()

    def on_llm_error(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> Any:
        self.on_llm_error_common()

    def on_chain_start(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> Any:
        self.on_chain_start_common()

    def on_chain_end(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> Any:
        self.on_chain_end_common()

    def on_chain_error(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> Any:
        self.on_chain_error_common()

    def on_tool_start(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> Any:
        self.on_tool_start_common()

    def on_tool_end(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> Any:
        self.on_tool_end_common()

    def on_tool_error(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> Any:
        self.on_tool_error_common()

    def on_agent_action(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> Any:
        self.on_agent_action_common()

    def on_agent_finish(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> Any:
        self.on_agent_finish_common()

    def on_text(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> Any:
        self.on_text_common()

    def __deepcopy__(self, memo: dict) -> "FakeCallbackHandler":
        return self


class FakeAsyncCallbackHandler(AsyncCallbackHandler, BaseFakeCallbackHandlerMixin):
    """Fake async callback handler for testing."""

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

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

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

    async def on_llm_start(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> None:
        self.on_llm_start_common()

    async def on_llm_new_token(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> None:
        self.on_llm_new_token_common()

    async def on_llm_end(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> None:
        self.on_llm_end_common()

    async def on_llm_error(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> None:
        self.on_llm_error_common()

    async def on_chain_start(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> None:
        self.on_chain_start_common()

    async def on_chain_end(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> None:
        self.on_chain_end_common()

    async def on_chain_error(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> None:
        self.on_chain_error_common()

    async def on_tool_start(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> None:
        self.on_tool_start_common()

    async def on_tool_end(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> None:
        self.on_tool_end_common()

    async def on_tool_error(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> None:
        self.on_tool_error_common()

    async def on_agent_action(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> None:
        self.on_agent_action_common()

    async def on_agent_finish(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> None:
        self.on_agent_finish_common()

    async def on_text(
        self,
        *args: Any,
        **kwargs: Any,
    ) -> None:
        self.on_text_common()

    def __deepcopy__(self, memo: dict) -> "FakeAsyncCallbackHandler":
        return self