Add sqlite store implementation

[VMinB12]

Currently, there is a store implementation for in memory and postgres, but not yet one for sqlite. In memory is easy to use, but it lacks persistence. Postgres has persistence, but requires a separately running service. It would be really great to have the ease of use of sqlite to have a persistent store implementation. Is that something you are looking to implement?

Specifically, we currently have:

from langgraph.store.postgres import PostgresStore
from langgraph.store.memory import InMemoryStore

and this is a feature request for

from langgraph.store.sqlite import SQLiteStore

[rambip]

I agree that it would be very useful. In particular, right now I try to use sqlite manually and I get this error:

SQLite objects created in a thread can only be used in that same thread. The object was created in thread id 140669698430784 and this is thread id 140669008488128.

This is even more irritating because langchain does support sqlite with vectore store extension: https://python.langchain.com/docs/integrations/vectorstores/sqlitevec/

[larruda]

http://python.langchain.com/api_reference/community/storage/langchain_community.storage.sql.SQLStore.html

[MaoJianwei]

agree, I also need it.

[lucasarruda-ciandt]

It's already there!! Just made it work.
look for class SqliteStore at langgraph/store/sqlite/base.py