Now I just import sessionmaker in dao classes and do what I need to:

class BaseDAO:
    model = None

    @classmethod
    async def find_all(cls, **filter_by):
        async with async_session() as session:
            query = select(cls.model).filter_by(**filter_by)
            result = await session.execute(query)
            return result.scalars().all()

I know that there are two other ways:

1. pass session in endpoint via Depends(get_db):

def get_db() -> Generator:  # pragma: no cover
    """
    Returns a generator that yields a database session

    Yields:
        Session: A database session object.

    Raises:
        Exception: If an error occurs while getting the database session.
    """

    log.debug("getting database session")
    db = get_local_session(SQLALCHEMY_DATABASE_URL, False)()
    try:
        yield db
    finally:  # pragma: no cover
        log.debug("closing database session")
        db.close()  # pragma: no cover

@router.post("/register")
def register(user_register: UserRegister, db: Session = Depends(get_db)):

2. The most unclear one. But I was told that it is the best way:
   a. By pointing the dependency to an abstract base class rather than a concrete class. This may be a good idea from a code structuring point of view, but can be difficult to describe when we depend on third party classes

class MyProto(abc.ABC):
    ...

@router.get
def my_view_funcion(param: MyProto = Depends()): 
    ...

app = FastApi()
app.dependency_overrides[MyProto] = some_session_factory

b. Pointing a dependency to a stub function that doesn’t actually do anything. This can also be used to mark dependencies of the same type, but which should have different meanings.

def get_session_stub():
    raise NotImplementedError  # это реально тело этой функции
    
@router.get
def my_view_funcion(param: Session = Depends(get_session_stub)): 
    ...

app = FastApi()
app.dependency_overrides[get_session_stub] = some_session_factory

It would be great if you could explain to me the last strategy. If it’s good, of course 🙂