Message Persistence
Info
To learn about how to load previous messages and agent states, check out the Loading Message History and Loading Agent State pages.
To persist LangGraph messages to a database, you can use either AsyncPostgresSaver or AsyncSqliteSaver. Set up the asynchronous memory by configuring the graph within a lifespan function, as follows:
from fastapi import FastAPI
from contextlib import asynccontextmanager
from langgraph.checkpoint.postgres.aio import AsyncPostgresSaver
from copilotkit import LangGraphAGUIAgent
from ag_ui_langgraph import add_langgraph_fastapi_endpoint
graph = None
@asynccontextmanager
async def lifespan(app: FastAPI):
async with AsyncPostgresSaver.from_conn_string(
"postgresql://postgres:postgres@127.0.0.1:5432/postgres"
) as checkpointer:
# NOTE: you need to call .setup() the first time you're using your checkpointer
await checkpointer.setup()
# Create an async graph
graph = workflow.compile(checkpointer=checkpointer)
yield
# Create SDK with the graph
app = FastAPI(lifespan=lifespan)
add_langgraph_fastapi_endpoint(
app=app,
agent=LangGraphAGUIAgent(
name="research_agent",
description="Research agent.",
graph=graph,
),
path="/agents/research_agent"
)
To learn more about persistence in LangGraph, check out the LangGraph documentation.