What are the best practices for creating an agent in a FastAPI project?

[telecomshy]

According to the official documentation, the way to create and use a PostgresSaver and an Agent is as follows:

DB_URI = "postgres://postgres:postgres@localhost:5432/postgres?sslmode=disable"
with PostgresSaver.from_conn_string(DB_URI) as checkpointer:
    # call .setup() the first time you're using the checkpointer
    checkpointer.setup()
    agent = create_react_agent(llm, tools, checkpointer=checkpointer)
    ...

However, I cannot do this within a route function because creating a new checkpointer instance on every request prevents retrieving the stored conversation history via the config.

My question is: Can I create the checkpointer within a lifespan function instead? For example:

@contextmanager
def lifespan(_: FastAPI):
    with PostgresSaver.from_conn_string(DB_URI) as checkpointer:
        checkpointer.setup()
        yield {"checkpointer": checkpointer}

In this case, would the entire FastAPI app use only a single connection, and would this connection remain unreleased until the app shuts down?

Based on this article: #1357, I think that using a connection pool is a good approach, but besides that, are there any other alternatives? What are the best practices for creating an agent in a FastAPI project?