MomentoChatMessageHistory#

class langchain_community.chat_message_histories.momento.MomentoChatMessageHistory(session_id: str, cache_client: momento.CacheClient, cache_name: str, *, key_prefix: str = 'message_store:', ttl: timedelta | None = None, ensure_cache_exists: bool = True)[source]#

Chat message history cache that uses Momento as a backend.

See https://gomomento.com/

Instantiate a chat message history cache that uses Momento as a backend.

Note: to instantiate the cache client passed to MomentoChatMessageHistory, you must have a Momento account at https://gomomento.com/.

Parameters:

session_id (str) – The session ID to use for this chat session.
cache_client (CacheClient) – The Momento cache client.
cache_name (str) – The name of the cache to use to store the messages.
key_prefix (str, optional) – The prefix to apply to the cache key. Defaults to “message_store:”.
ttl (Optional[timedelta], optional) – The TTL to use for the messages. Defaults to None, ie the default TTL of the cache will be used.
ensure_cache_exists (bool, optional) – Create the cache if it doesn’t exist. Defaults to True.

Raises:

ImportError – Momento python package is not installed.
TypeError – cache_client is not of type momento.CacheClientObject

Attributes

messages

Retrieve the messages from Momento.

Methods

`__init__`(session_id, cache_client, cache_name, *)	Instantiate a chat message history cache that uses Momento as a backend.
`aadd_messages`(messages)	Async add a list of messages.
`aclear`()	Async remove all messages from the store
`add_ai_message`(message)	Convenience method for adding an AI message string to the store.
`add_message`(message)	Store a message in the cache.
`add_messages`(messages)	Add a list of messages.
`add_user_message`(message)	Convenience method for adding a human message string to the store.
`aget_messages`()	Async version of getting messages.
`clear`()	Remove the session's messages from the cache.
`from_client_params`(session_id, cache_name, ...)	Construct cache from CacheClient parameters.

__init__(session_id: str, cache_client: momento.CacheClient, cache_name: str, *, key_prefix: str = 'message_store:', ttl: timedelta | None = None, ensure_cache_exists: bool = True)[source]#

Instantiate a chat message history cache that uses Momento as a backend.

Note: to instantiate the cache client passed to MomentoChatMessageHistory, you must have a Momento account at https://gomomento.com/.

Parameters:

session_id (str) – The session ID to use for this chat session.
cache_client (CacheClient) – The Momento cache client.
cache_name (str) – The name of the cache to use to store the messages.
key_prefix (str, optional) – The prefix to apply to the cache key. Defaults to “message_store:”.
ttl (Optional[timedelta], optional) – The TTL to use for the messages. Defaults to None, ie the default TTL of the cache will be used.
ensure_cache_exists (bool, optional) – Create the cache if it doesn’t exist. Defaults to True.

Raises:

ImportError – Momento python package is not installed.
TypeError – cache_client is not of type momento.CacheClientObject

async aadd_messages(messages: Sequence[BaseMessage]) → None#

Async add a list of messages.

Parameters:: messages (Sequence[BaseMessage]) – A sequence of BaseMessage objects to store.
Return type:: None

async aclear() → None#

Async remove all messages from the store

Return type:: None

add_ai_message(message: AIMessage | str) → None#

Convenience method for adding an AI message string to the store.

Please note that this is a convenience method. Code should favor the bulk add_messages interface instead to save on round-trips to the underlying persistence layer.

This method may be deprecated in a future release.

Parameters:: message (AIMessage | str) – The AI message to add.
Return type:: None

add_message(message: BaseMessage) → None[source]#

Store a message in the cache.

Parameters:

message (BaseMessage) – The message object to store.

Raises:

SdkException – Momento service or network error.
Exception – Unexpected response.

Return type:

None

add_messages(messages: Sequence[BaseMessage]) → None#

Add a list of messages.

Implementations should over-ride this method to handle bulk addition of messages in an efficient manner to avoid unnecessary round-trips to the underlying store.

Parameters:: messages (Sequence[BaseMessage]) – A sequence of BaseMessage objects to store.
Return type:: None

add_user_message(message: HumanMessage | str) → None#

Convenience method for adding a human message string to the store.

Please note that this is a convenience method. Code should favor the bulk add_messages interface instead to save on round-trips to the underlying persistence layer.

This method may be deprecated in a future release.

Parameters:: message (HumanMessage | str) – The human message to add to the store.
Return type:: None

async aget_messages() → List[BaseMessage]#

Async version of getting messages.

Can over-ride this method to provide an efficient async implementation.

In general, fetching messages may involve IO to the underlying persistence layer.

Return type:: List[BaseMessage]

clear() → None[source]#

Remove the session’s messages from the cache.

Raises:

SdkException – Momento service or network error.
Exception – Unexpected response.

Return type:

None

classmethod from_client_params(session_id: str, cache_name: str, ttl: timedelta, *, configuration: momento.config.Configuration | None = None, api_key: str | None = None, auth_token: str | None = None, **kwargs: Any) → MomentoChatMessageHistory[source]#

Construct cache from CacheClient parameters.

Parameters:

session_id (str) –
cache_name (str) –
ttl (timedelta) –
configuration (Optional[momento.config.Configuration]) –
api_key (Optional[str]) –
auth_token (Optional[str]) –
kwargs (Any) –

Return type:

MomentoChatMessageHistory

Examples using MomentoChatMessageHistory