Spaces:
Runtime error
Runtime error
File size: 4,127 Bytes
129cd69 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 |
"""Astra DB - based chat message history, based on astrapy."""
from __future__ import annotations
import json
import time
import typing
from typing import List, Optional
if typing.TYPE_CHECKING:
from astrapy.db import AstraDB as LibAstraDB
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"
class AstraDBChatMessageHistory(BaseChatMessageHistory):
"""Chat message history that stores history in Astra DB.
Args (only keyword-arguments accepted):
session_id: arbitrary key that is used to store the messages
of a single chat session.
collection_name (str): name of the Astra DB collection to create/use.
token (Optional[str]): API token for Astra DB usage.
api_endpoint (Optional[str]): full URL to the API endpoint,
such as "https://<DB-ID>-us-east1.apps.astra.datastax.com".
astra_db_client (Optional[Any]): *alternative to token+api_endpoint*,
you can pass an already-created 'astrapy.db.AstraDB' instance.
namespace (Optional[str]): namespace (aka keyspace) where the
collection is created. Defaults to the database's "default namespace".
"""
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[LibAstraDB] = None, # type 'astrapy.db.AstraDB'
namespace: Optional[str] = None,
) -> None:
"""Create an Astra DB chat message history."""
try:
from astrapy.db import AstraDB as LibAstraDB
except (ImportError, ModuleNotFoundError):
raise ImportError(
"Could not import a recent astrapy python package. "
"Please install it with `pip install --upgrade astrapy`."
)
# Conflicting-arg checks:
if astra_db_client is not None:
if token is not None or api_endpoint is not None:
raise ValueError(
"You cannot pass 'astra_db_client' to AstraDB if passing "
"'token' and 'api_endpoint'."
)
self.session_id = session_id
self.collection_name = collection_name
self.token = token
self.api_endpoint = api_endpoint
self.namespace = namespace
if astra_db_client is not None:
self.astra_db = astra_db_client
else:
self.astra_db = LibAstraDB(
token=self.token,
api_endpoint=self.api_endpoint,
namespace=self.namespace,
)
self.collection = self.astra_db.create_collection(self.collection_name)
@property
def messages(self) -> List[BaseMessage]: # type: ignore
"""Retrieve all session messages from DB"""
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
def add_message(self, message: BaseMessage) -> None:
"""Write a message to the table"""
self.collection.insert_one(
{
"timestamp": time.time(),
"session_id": self.session_id,
"body_blob": json.dumps(message_to_dict(message)),
}
)
def clear(self) -> None:
"""Clear session memory from DB"""
self.collection.delete_many(filter={"session_id": self.session_id})
|