langchain verbose callback example

verbose-callback.py

# from langchain.callbacks.stdout import StdOutCallbackHandler
from langchain.callbacks.base import BaseCallbackHandler
from typing import Any, Dict, List, Optional, Union

class VerboseCallbackHandler(BaseCallbackHandler):
    """Callback Handler that prints to std out."""

    def __init__(self, color: Optional[str] = None):
        print(color)

    def on_llm_start(
        self, serialized: Dict[str, Any], prompts: List[str], **kwargs: Any
    ) -> None:
        print(serialized)

    def on_llm_end(self, response, **kwargs: Any) -> None:
        print(response)

    def on_llm_new_token(self, token: str, **kwargs: Any) -> None:
        print(token)

    def on_llm_error(
        self, error: Union[Exception, KeyboardInterrupt], **kwargs: Any
    ) -> None:
        print(error)

    def on_chain_start(
        self, serialized: Dict[str, Any], inputs: Dict[str, Any], **kwargs: Any
    ) -> None:
        # class_name = serialized["name"]
        print(serialized)

    def on_chain_end(self, outputs: Dict[str, Any], **kwargs: Any) -> None:
        print(outputs)

    def on_chain_error(
        self, error: Union[Exception, KeyboardInterrupt], **kwargs: Any
    ) -> None:
        print(error)

    def on_tool_start(
        self,
        serialized: Dict[str, Any],
        input_str: str,
        **kwargs: Any,
    ) -> None:
        print(serialized)

    def on_agent_action(
        self, action, color: Optional[str] = None, **kwargs: Any
    ) -> Any:
        """Run on agent action."""
        print(action)

    def on_tool_end(
        self,
        output: str,
        color: Optional[str] = None,
        observation_prefix: Optional[str] = None,
        llm_prefix: Optional[str] = None,
        **kwargs: Any,
    ) -> None:
        """If not the final action, print out observation."""
        if observation_prefix:
            print(f"\n{observation_prefix}")
        print(output)
        if llm_prefix:
            print(f"\n{llm_prefix}")

    def on_tool_error(
        self, error: Union[Exception, KeyboardInterrupt], **kwargs: Any
    ) -> None:
        print(error)

    def on_text(
        self,
        text: Optional[str] = None,
        color: Optional[str] = None,
        end: str = "",
        **kwargs: Optional[str],
    ) -> None:
        print(text)

    def on_agent_finish(
        self, finish, color: Optional[str] = None, **kwargs: Any
    ) -> None:
        print(finish)