import json
import logging
from time import time
from typing import TYPE_CHECKING, List, Optional, Sequence
from langchain_core.chat_history import BaseChatMessageHistory
from langchain_core.messages import BaseMessage, message_to_dict, messages_from_dict
from langchain_elasticsearch._utilities import with_user_agent_header
from langchain_elasticsearch.client import create_elasticsearch_client
if TYPE_CHECKING:
from elasticsearch import Elasticsearch
logger = logging.getLogger(__name__)
class ElasticsearchChatMessageHistory(BaseChatMessageHistory):
"""Chat message history that stores history in Elasticsearch.
Args:
es_url: URL of the Elasticsearch instance to connect to.
es_cloud_id: Cloud ID of the Elasticsearch instance to connect to.
es_user: Username to use when connecting to Elasticsearch.
es_password: Password to use when connecting to Elasticsearch.
es_api_key: API key to use when connecting to Elasticsearch.
es_connection: Optional pre-existing Elasticsearch connection.
esnsure_ascii: Used to escape ASCII symbols in json.dumps. Defaults to True.
index: Name of the index to use.
session_id: Arbitrary key that is used to store the messages
of a single chat session.
For synchronous applications, use the `ElasticsearchChatMessageHistory` class.
For asyhchronous applications, use the `AsyncElasticsearchChatMessageHistory` class.
"""
[docs]
def __init__(
self,
index: str,
session_id: str,
*,
es_connection: Optional["Elasticsearch"] = None,
es_url: Optional[str] = None,
es_cloud_id: Optional[str] = None,
es_user: Optional[str] = None,
es_api_key: Optional[str] = None,
es_password: Optional[str] = None,
esnsure_ascii: Optional[bool] = True,
):
self.index: str = index
self.session_id: str = session_id
self.ensure_ascii = esnsure_ascii
# Initialize Elasticsearch client from passed client arg or connection info
if es_connection is not None:
self.client = es_connection
elif es_url is not None or es_cloud_id is not None:
try:
self.client = create_elasticsearch_client(
url=es_url,
username=es_user,
password=es_password,
cloud_id=es_cloud_id,
api_key=es_api_key,
)
except Exception as err:
logger.error(f"Error connecting to Elasticsearch: {err}")
raise err
else:
raise ValueError(
"""Either provide a pre-existing Elasticsearch connection, \
or valid credentials for creating a new connection."""
)
self.client = with_user_agent_header(self.client, "langchain-py-ms")
self.created = False
[docs]
def create_if_missing(self) -> None:
if not self.created:
if self.client.indices.exists(index=self.index):
logger.debug(
(
f"Chat history index {self.index} already exists, "
"skipping creation."
)
)
else:
logger.debug(f"Creating index {self.index} for storing chat history.")
self.client.indices.create(
index=self.index,
mappings={
"properties": {
"session_id": {"type": "keyword"},
"created_at": {"type": "date"},
"history": {"type": "text"},
}
},
)
self.created = True
[docs]
def get_messages(self) -> List[BaseMessage]: # type: ignore[override]
"""Retrieve the messages from Elasticsearch"""
try:
from elasticsearch import ApiError
self.create_if_missing()
result = self.client.search(
index=self.index,
query={"term": {"session_id": self.session_id}},
sort="created_at:asc",
)
except ApiError as err:
logger.error(f"Could not retrieve messages from Elasticsearch: {err}")
raise err
if result and len(result["hits"]["hits"]) > 0:
items = [
json.loads(document["_source"]["history"])
for document in result["hits"]["hits"]
]
else:
items = []
return messages_from_dict(items)
[docs]
def add_message(self, message: BaseMessage) -> None:
"""Add messages to the chat session in Elasticsearch"""
try:
from elasticsearch import ApiError
self.create_if_missing()
self.client.index(
index=self.index,
document={
"session_id": self.session_id,
"created_at": round(time() * 1000),
"history": json.dumps(
message_to_dict(message),
ensure_ascii=bool(self.ensure_ascii),
),
},
refresh=True,
)
except ApiError as err:
logger.error(f"Could not add message to Elasticsearch: {err}")
raise err
[docs]
def add_messages(self, messages: Sequence[BaseMessage]) -> None:
for message in messages:
self.add_message(message)
[docs]
def clear(self) -> None:
"""Clear session memory in Elasticsearch"""
try:
from elasticsearch import ApiError
self.create_if_missing()
self.client.delete_by_query(
index=self.index,
query={"term": {"session_id": self.session_id}},
refresh=True,
)
except ApiError as err:
logger.error(f"Could not clear session memory in Elasticsearch: {err}")
raise err
