langchain-python/langchain/load/serializable.py

from abc import ABC
from typing import Any, Dict, List, Literal, TypedDict, Union, cast

from pydantic import BaseModel, PrivateAttr


class BaseSerialized(TypedDict):
    lc: int
    id: List[str]


class SerializedConstructor(BaseSerialized):
    type: Literal["constructor"]
    kwargs: Dict[str, Any]


class SerializedSecret(BaseSerialized):
    type: Literal["secret"]


class SerializedNotImplemented(BaseSerialized):
    type: Literal["not_implemented"]


class Serializable(BaseModel, ABC):
    @property
    def lc_serializable(self) -> bool:
        """
        Return whether or not the class is serializable.
        """
        return False

    @property
    def lc_namespace(self) -> List[str]:
        """
        Return the namespace of the langchain object.
        eg. ["langchain", "llms", "openai"]
        """
        return self.__class__.__module__.split(".")

    @property
    def lc_secrets(self) -> Dict[str, str]:
        """
        Return a map of constructor argument names to secret ids.
        eg. {"openai_api_key": "OPENAI_API_KEY"}
        """
        return dict()

    @property
    def lc_attributes(self) -> Dict:
        """
        Return a list of attribute names that should be included in the
        serialized kwargs. These attributes must be accepted by the
        constructor.
        """
        return {}

    class Config:
        extra = "ignore"

    _lc_kwargs = PrivateAttr(default_factory=dict)

    def __init__(self, **kwargs: Any) -> None:
        super().__init__(**kwargs)
        self._lc_kwargs = kwargs

    def to_json(self) -> Union[SerializedConstructor, SerializedNotImplemented]:
        if not self.lc_serializable:
            return self.to_json_not_implemented()

        secrets = dict()
        # Get latest values for kwargs if there is an attribute with same name
        lc_kwargs = {
            k: getattr(self, k, v)
            for k, v in self._lc_kwargs.items()
            if not (self.__exclude_fields__ or {}).get(k, False)  # type: ignore
        }

        # Merge the lc_secrets and lc_attributes from every class in the MRO
        for cls in [None, *self.__class__.mro()]:
            # Once we get to Serializable, we're done
            if cls is Serializable:
                break

            # Get a reference to self bound to each class in the MRO
            this = cast(Serializable, self if cls is None else super(cls, self))

            secrets.update(this.lc_secrets)
            lc_kwargs.update(this.lc_attributes)

        return {
            "lc": 1,
            "type": "constructor",
            "id": [*self.lc_namespace, self.__class__.__name__],
            "kwargs": lc_kwargs
            if not secrets
            else _replace_secrets(lc_kwargs, secrets),
        }

    def to_json_not_implemented(self) -> SerializedNotImplemented:
        return to_json_not_implemented(self)


def _replace_secrets(
    root: Dict[Any, Any], secrets_map: Dict[str, str]
) -> Dict[Any, Any]:
    result = root.copy()
    for path, secret_id in secrets_map.items():
        [*parts, last] = path.split(".")
        current = result
        for part in parts:
            if part not in current:
                break
            current[part] = current[part].copy()
            current = current[part]
        if last in current:
            current[last] = {
                "lc": 1,
                "type": "secret",
                "id": [secret_id],
            }
    return result


def to_json_not_implemented(obj: object) -> SerializedNotImplemented:
    _id: List[str] = []
    try:
        if hasattr(obj, "__name__"):
            _id = [*obj.__module__.split("."), obj.__name__]
        elif hasattr(obj, "__class__"):
            _id = [*obj.__class__.__module__.split("."), obj.__class__.__name__]
    except Exception:
        pass
    return {
        "lc": 1,
        "type": "not_implemented",
        "id": _id,
    }