Serving the app via FastAPI

The last step of the tutorial is to demonstrate how lato can be integrated with a web framework of your choice. For now, let’s look at the FastAPI example:

from fastapi import FastAPI
from application import Application, create_app
from queries import GetAllTodos

api = FastAPI()
api.lato_application = create_app()

async def get_application(request: Request) -> Application:
    Retrieve the application instance from the request.

    :param request: The incoming request.
    :return: The Application instance.
    app =
    return app

async def root(app: Annotated[Application, Depends(get_application)]):
    result = await app.execute_async(GetAllTodos())
    return {"todos": result}

FastAPI supports async / await syntax, and we take advantage of it by using await app.execute_async(...) instead of app.execute(...) we used before.

See Concurrency for more details on writing concurrent code in Lato.

This concludes the tutorial.