DeclarativeContainer of DeclarativeContainers

As documentation shows “Bundles” and “Use cases” mini applications, we can prepare quite great containers with super clean dependencies. Declarative containers is my choice of keeping everything in place, that’s why I would like to see declarative containers even more usable.

Building whole application with its bundles and dependencies happens in functions. I would love to move that code to somewhat declarative containers too.

By doodling around a few hours I couldn’t figure it out how to archive this by Callables or Factories. So lets introduce some kind of providers.SubContainer.

Below there is naive example of bundle containers and application container which orchestrate whole project in declarative way.

# bundles/users/containers.py
from dependency_injector import containers, providers

from bundles.users.repositories import PGRepository
from bundles.users.commands import UserCommands


class PGAdapters(containers.DeclarativeContainer):
    user_repository = providers.Factory(PGRepositry)

class InMemoryAdapters(containers.DeclarativeContainer):
    user_repository = providers.Factory(InMemoryRepositry)

class Users(containers.DeclarativeContainer):
    adapters = providers.DependenciesContainer()

    commands = providers.Factory(
        UserCommands,
        user_repository=adapters.user_repository,
    )

# containers.py
from dependency_injector import containers, providers

from bundles import users, photos
from main import main


class Env1Adapters(containers.DeclarativeContainer):
    config = providers.Configuration('config')

    users_adapters = providers.SubContainer(users.PGAdapters)
    photos_adapters = providers.SubContainer(
        photos.S3Adapters,
        config=config,
    )

class Env2Adapters(containers.DeclarativeContainer):
    users_adapters = providers.SubContainer(users.InMemoryAdapters)
    photos_adapters = providers.SubContainer(photos.TmpDirAdapters)

class FooBarAdapters(containers.DeclarativeContainer):
    users_adapters = providers.SubContainer(users.FooAdapters)
    photos_adapters = providers.SubContainer(photos.BarAdapters)

class Application(containers.DeclarativeContainer):
    adapters = providers.DependenciesContainer()
    config = providers.Configuration('config')

    users = proviers.SubContainer(
        users.UserContainer,
        adapters=adapters.users_adapters,
    )
    photos = proviers.SubContainer(
        photos.PhotosContainer,
        adapters=adapters.photos_adapters,
    )

    main = providers.Callable(
        main,
        users=users,
        photos=photos,
    )

# run.py
from containers import Env1Adapters, Application

if __name__ == '__main__':
    config = {}

    adapters = Env1Adapters(config=config)  # or any other method to point adapters set
    application = Application(adapters=adapters, config=config)
    application.main()

[approxit]

Great news, and works as a charm! Happy to have it implemented, even if your previous “work around” surprisingly obvious. 😃

[rmk135]

UPDATE: There is a new provider for the mentioned case. It’s called the Container. The example can be found in tests - https://github.com/ets-labs/python-dependency-injector/blob/520945483f9b073bbe28aa3194bbb54a14cbdd86/tests/unit/providers/test_container_py2_py3.py#L40