Source code for langchain_community.chat_message_histories.astradb

"""Astra DB - based chat message history, based on astrapy."""
from __future__ import annotations

import json
import time
from typing import TYPE_CHECKING, List, Optional, Sequence

from langchain_community.utilities.astradb import (
    SetupMode,
    _AstraDBCollectionEnvironment,
)

if TYPE_CHECKING:
    from astrapy.db import AstraDB, AsyncAstraDB

from langchain_core._api.deprecation import deprecated
from langchain_core.chat_history import BaseChatMessageHistory
from langchain_core.messages import (
    BaseMessage,
    message_to_dict,
    messages_from_dict,
)

DEFAULT_COLLECTION_NAME = "langchain_message_store"


[docs]@deprecated( since="0.0.25", removal="0.3.0", alternative_import="langchain_astradb.AstraDBChatMessageHistory", ) class AstraDBChatMessageHistory(BaseChatMessageHistory):
[docs] def __init__( self, *, session_id: str, collection_name: str = DEFAULT_COLLECTION_NAME, token: Optional[str] = None, api_endpoint: Optional[str] = None, astra_db_client: Optional[AstraDB] = None, async_astra_db_client: Optional[AsyncAstraDB] = None, namespace: Optional[str] = None, setup_mode: SetupMode = SetupMode.SYNC, pre_delete_collection: bool = False, ) -> None: """Chat message history that stores history in Astra DB. Args: session_id: arbitrary key that is used to store the messages of a single chat session. collection_name: name of the Astra DB collection to create/use. token: API token for Astra DB usage. api_endpoint: full URL to the API endpoint, such as "https://<DB-ID>-us-east1.apps.astra.datastax.com". astra_db_client: *alternative to token+api_endpoint*, you can pass an already-created 'astrapy.db.AstraDB' instance. async_astra_db_client: *alternative to token+api_endpoint*, you can pass an already-created 'astrapy.db.AsyncAstraDB' instance. namespace: namespace (aka keyspace) where the collection is created. Defaults to the database's "default namespace". setup_mode: mode used to create the Astra DB collection (SYNC, ASYNC or OFF). pre_delete_collection: whether to delete the collection before creating it. If False and the collection already exists, the collection will be used as is. """ self.astra_env = _AstraDBCollectionEnvironment( collection_name=collection_name, token=token, api_endpoint=api_endpoint, astra_db_client=astra_db_client, async_astra_db_client=async_astra_db_client, namespace=namespace, setup_mode=setup_mode, pre_delete_collection=pre_delete_collection, ) self.collection = self.astra_env.collection self.async_collection = self.astra_env.async_collection self.session_id = session_id self.collection_name = collection_name
@property def messages(self) -> List[BaseMessage]: """Retrieve all session messages from DB""" self.astra_env.ensure_db_setup() message_blobs = [ doc["body_blob"] for doc in sorted( self.collection.paginated_find( filter={ "session_id": self.session_id, }, projection={ "timestamp": 1, "body_blob": 1, }, ), key=lambda _doc: _doc["timestamp"], ) ] items = [json.loads(message_blob) for message_blob in message_blobs] messages = messages_from_dict(items) return messages @messages.setter def messages(self, messages: List[BaseMessage]) -> None: raise NotImplementedError("Use add_messages instead")
[docs] async def aget_messages(self) -> List[BaseMessage]: await self.astra_env.aensure_db_setup() docs = self.async_collection.paginated_find( filter={ "session_id": self.session_id, }, projection={ "timestamp": 1, "body_blob": 1, }, ) sorted_docs = sorted( [doc async for doc in docs], key=lambda _doc: _doc["timestamp"], ) message_blobs = [doc["body_blob"] for doc in sorted_docs] items = [json.loads(message_blob) for message_blob in message_blobs] messages = messages_from_dict(items) return messages
[docs] def add_messages(self, messages: Sequence[BaseMessage]) -> None: self.astra_env.ensure_db_setup() docs = [ { "timestamp": time.time(), "session_id": self.session_id, "body_blob": json.dumps(message_to_dict(message)), } for message in messages ] self.collection.chunked_insert_many(docs)
[docs] async def aadd_messages(self, messages: Sequence[BaseMessage]) -> None: await self.astra_env.aensure_db_setup() docs = [ { "timestamp": time.time(), "session_id": self.session_id, "body_blob": json.dumps(message_to_dict(message)), } for message in messages ] await self.async_collection.chunked_insert_many(docs)
[docs] def clear(self) -> None: self.astra_env.ensure_db_setup() self.collection.delete_many(filter={"session_id": self.session_id})
[docs] async def aclear(self) -> None: await self.astra_env.aensure_db_setup() await self.async_collection.delete_many(filter={"session_id": self.session_id})