Fast Api Multi Folder

[pierresigwalt]

So, I have followed the FastApi Example, everything works when everything is in one file. However I am having hard time when trying to put some order in the organisation (Circular dependency) and can't see how to avoid this (I kind of follow litestart organisation because I like the approach):

My Current Setup is the following:

app/
├── main.py
├── domain
│ ├── dependencies.py
├── server
│ ├── dependencies.py

• main.py

idp_app = FastAPI(
    swagger_ui_parameters={
        "syntaxHighlight.theme": "obsidian"
    },
    lifespan=lifespan,
    title=openapi_info["title"],
    version=openapi_info["version"],
    description=openapi_info["description"],
    contact=openapi_info["contact"],
    license_info=openapi_info["license_info"],
)

for router in app_routers:
    idp_app.include_router(router)


alchemy = StarletteAdvancedAlchemy(config=db_config, app=idp_app)

• domain/dependencies.py

async def provide_user_service(
    db_session: Annotated[AsyncSession, Depends(provide_db_session)],
) -> AsyncGenerator[UserService, None]:
    """This provides the default Authors repository."""
    async with UserService.new(
        session=db_session,
    ) as service:
        yield service

• server/dependencies.py

async def provide_db_session(request: Request) -> AsyncSession:
    """Provide a DB session."""
    return alchemy.get_session(request)

However as main.py alchemy variable need the app (FastApi) I can't really move it out from the main.py from my knowledge off course, bringing the issue of the dependency.

So the question is:
How can I create alchemy->provide_db_session outside of the main.py and be able to include the app to StarletteAdvancedAlchemy

Many thank for the help, hopefully it's clear.

[nvanmeurs]

@pierresigwalt Did you ever figure it out?

[Priestch]

I think you can initialize the alchemy object with the default app, which is None by default in a individual module, then import and call it's init_app in main.py, the import alchemy statement in other modules should work.

advanced-alchemy/advanced_alchemy/extensions/starlette.py

Lines 112 to 132 in 9549268

	def init_app(self, app: Starlette) -> None:
	"""Initializes the Starlette application with SQLAlchemy engine and sessionmaker.
	Sets up middleware and shutdown handlers for managing the database engine.
	Args:
	app (starlette.applications.Starlette): The Starlette application instance.
	"""
	engine = self.config.get_engine()
	self.engine_key = self._make_unique_state_key(app, f"sqla_engine_{engine.name}")
	self.sessionmaker_key = self._make_unique_state_key(app, f"sqla_sessionmaker_{engine.name}")
	self.session_key = f"sqla_session_{self.sessionmaker_key}"
	setattr(app.state, self.engine_key, engine)
	setattr(app.state, self.sessionmaker_key, self.config.create_session_maker())
	app.add_middleware(BaseHTTPMiddleware, dispatch=self.middleware_dispatch)
	app.add_event_handler("shutdown", self.on_shutdown) # pyright: ignore[reportUnknownMemberType]
	self._app = app