Momento Cache

Momento Cache is the world's first truly serverless caching service. It provides instant elasticity, scale-to-zero capability, and blazing-fast performance.

This notebook goes over how to use Momento Cache to store chat message history using the MomentoChatMessageHistory class. See the Momento docs for more detail on how to get set up with Momento.

Note that, by default we will create a cache if one with the given name doesn't already exist.

You'll need to get a Momento API key to use this class. This can either be passed in to a momento.CacheClient if you'd like to instantiate that directly, as a named parameter api_key to MomentoChatMessageHistory.from_client_params, or can just be set as an environment variable MOMENTO_API_KEY.

from datetime import timedelta

from langchain_community.chat_message_histories import MomentoChatMessageHistory

session_id = "foo"
cache_name = "langchain"
ttl = timedelta(days=1)
history = MomentoChatMessageHistory.from_client_params(
    session_id,
    cache_name,
    ttl,
)

history.add_user_message("hi!")

history.add_ai_message("whats up?")

API Reference:

• MomentoChatMessageHistory

history.messages

[HumanMessage(content='hi!', additional_kwargs={}, example=False),
 AIMessage(content='whats up?', additional_kwargs={}, example=False)]