Resource Factory for Short-Lived Session Objects

Hi @rmk135

You did a great job with this library! Thank you very much for that!

Yet, I’m having a hard time with a very common approach when using Resource: A database session should be created for each instance of get_user.

def create_db_session(db: Database):
  session = db.create_session()
    yield session
  db.close_session(session)

class APIContainer:
  database_session = providers.Resource(create_db_session)
  
class UseCaseContainer:
  api = providers.DependenciesContainer()

  get_user = providers.Factory(
    use_cases.GetUser, 
    database_session=api.database_session # `database_session` must be created for every instance of `get_user`
  ) 

But when running the application, it only creates ONE database session for the whole lifetime of the application, not N (the number of API calls).

How is it possible to create a database session for each get_user instance?

[m-vellinga]

Running into the same situation. Would love to have a database session that is essentially tied to a request/response cycle and all the dependancies that use it during that request/response cycle and closes up afterwards. It first sight the “Closing” marker does what we want but that only seems to work in combination with “Provide” when directly referencing the “Resource” not on dependancies that have the resource as a sub dependancy.

You would also need an idempotent shutdown for that on the Resource whenever you Provide multiple dependancies wrapped in a Closing that all reference that single Resource.

[rmk135]

Ok, I see what you’re looking for. I don’t think there is anything out-of-the box to make it work that way. This is an interesting problem. I would like to address it in the framework one day.