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Cassandra

Apache Cassandra® is a NoSQL, row-oriented, highly scalable and highly available database, well suited for storing large amounts of data.

Cassandra is a good choice for storing chat message history because it is easy to scale and can handle a large number of writes.

This notebook goes over how to use Cassandra to store chat message history.

Setting up​

To run this notebook you need either a running Cassandra cluster or a DataStax Astra DB instance running in the cloud (you can get one for free at datastax.com). Check cassio.org for more information.

%pip install --upgrade --quiet  "cassio>=0.1.0 langchain-community"

Set up the database connection parameters and secrets​

import getpass

database_mode = (input("\n(C)assandra or (A)stra DB? ")).upper()

keyspace_name = input("\nKeyspace name? ")

if database_mode == "A":
    ASTRA_DB_APPLICATION_TOKEN = getpass.getpass('\nAstra DB Token ("AstraCS:...") ')
    #
    ASTRA_DB_SECURE_BUNDLE_PATH = input("Full path to your Secure Connect Bundle? ")
elif database_mode == "C":
    CASSANDRA_CONTACT_POINTS = input(
        "Contact points? (comma-separated, empty for localhost) "
    ).strip()

Depending on whether local or cloud-based Astra DB, create the corresponding database connection "Session" object.

from cassandra.auth import PlainTextAuthProvider
from cassandra.cluster import Cluster

if database_mode == "C":
    if CASSANDRA_CONTACT_POINTS:
        cluster = Cluster(
            [cp.strip() for cp in CASSANDRA_CONTACT_POINTS.split(",") if cp.strip()]
        )
    else:
        cluster = Cluster()
    session = cluster.connect()
elif database_mode == "A":
    ASTRA_DB_CLIENT_ID = "token"
    cluster = Cluster(
        cloud={
            "secure_connect_bundle": ASTRA_DB_SECURE_BUNDLE_PATH,
        },
        auth_provider=PlainTextAuthProvider(
            ASTRA_DB_CLIENT_ID,
            ASTRA_DB_APPLICATION_TOKEN,
        ),
    )
    session = cluster.connect()
else:
    raise NotImplementedError

Example​

from langchain_community.chat_message_histories import (
    CassandraChatMessageHistory,
)

message_history = CassandraChatMessageHistory(
    session_id="test-session",
    session=session,
    keyspace=keyspace_name,
)

message_history.add_user_message("hi!")

message_history.add_ai_message("whats up?")
message_history.messages

Attribution statement​

Apache Cassandra, Cassandra and Apache are either registered trademarks or trademarks of the Apache Software Foundation in the United States and/or other countries.

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