BaseFakeCallbackHandler Class — langchain Architecture

Source Code

libs/langchain/tests/unit_tests/callbacks/fake_callback_handler.py lines 13–43

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
    ignore_retriever_: bool = False
    ignore_chat_model_: bool = False

    # to allow for similar callback handlers that are not technically equal
    fake_id: str | None = None

    # 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
    chat_model_starts: int = 0
    retriever_starts: int = 0
    retriever_ends: int = 0
    retriever_errors: int = 0
    retries: int = 0