Update bundles example (#292)

* Fix dependency provider stub issue with required init arg

* Refactor bundles example app

* Rename bundles package

* Rename bundles example container

* Rename bundles mini app to decoupled packages

* Move decoupled packages example to main examples

* Fix a typo

* Add meta

docs/examples-other/bundles_miniapp.rst

@@ -1,74 +0,0 @@
-Bundles mini application example
---------------------------------
-
-.. currentmodule:: dependency_injector.containers
-
-"Bundles" is an example mini application that is intended to demonstrate the
-power of dependency injection for creation of re-usable application components
-("bundles") with 100% transparency of their dependencies.
-
-Example application
-~~~~~~~~~~~~~~~~~~~
-
-"Bundles" mini application has next structure:
-
-.. code-block:: bash
-
-    bundles/
-        bundles/               <-- Bundles package
-            photos/            <-- Photos bundle
-                __init__.py    <-- Photos bundle dependency injection container
-                entities.py
-                repositories.py
-            users/             <-- Users bundle
-                __init__.py    <-- Users bundle dependency injection container
-                entities.py
-                repositories.py
-        run.py                 <-- Entrypoint
-
-
-IoC containers
-~~~~~~~~~~~~~~
-
-Next two listings show :py:class:`DeclarativeContainer`'s for "users" and 
-"photos" bundles.
-
-Listing of ``bundles/users/__init__.py``:
-
-.. literalinclude:: ../../examples/miniapps/bundles/bundles/users/__init__.py
-   :language: python
-
-.. note::
-
-    - ``Users`` container has dependency on database.
-
-Listing of ``bundles/photos/__init__.py``:
-
-.. literalinclude:: ../../examples/miniapps/bundles/bundles/photos/__init__.py
-   :language: python
-
-.. note::
-
-    - ``Photos`` container has dependencies on database and file storage.
-
-Run application
-~~~~~~~~~~~~~~~
-
-Finally, both "bundles" are initialized by providing needed dependencies.
-Initialization of dependencies happens right in the runtime, not earlier.
-Generally, it means, that any part of any bundle could be overridden on the
-fly.
-
-Listing of ``run.py``:
-
-.. literalinclude:: ../../examples/miniapps/bundles/run.py
-   :language: python
-
-Links
-~~~~~
-
-+ `Dependency Injector <https://github.com/ets-labs/python-dependency-injector/>`_
-+ `Full example sources <https://github.com/ets-labs/python-dependency-injector/tree/master/examples/miniapps/bundles>`_
-
-
-.. disqus::

docs/examples-other/index.rst

@@ -8,14 +8,11 @@ Other examples
                  of inversion of control principle and powered by 
                  "Dependency Injector" framework.
 
-Current section of documentation is designed to provide several example mini 
+This sections contains assorted ``Dependency Injector`` examples.
-applications that are built according to the inversion of control principle 
-and powered by *Dependency Injector* framework.
 
 ..  toctree::
     :maxdepth: 2
 
-    bundles_miniapp
     use_cases_miniapp
     password_hashing_miniapp
     chained_factories

docs/examples/decoupled-packages.rst

@@ -0,0 +1,130 @@
+Decoupled packages example (multiple containers)
+================================================
+
+.. meta::
+   :keywords: Python,Dependency Injection,Inversion of Control,Container,Example,Application,
+              Framework,AWS,boto3,client
+   :description: This example shows how to use Dependency Injector to create Python decoupled packages.
+                 To achieve a decoupling each package has a container with the components. When
+                 a component needs a dependency from the outside of the package scope we use the
+                 Dependency provider. The package container has no knowledge on where the
+                 dependencies come from. It states a need that the dependencies must be provided.
+                 This helps to decouple a package from the 3rd party dependencies and other
+                 packages.
+
+This example shows how to use ``Dependency Injector`` to create decoupled packages.
+
+To achieve a decoupling each package has a container with the components. When a component needs a
+dependency from the outside of the package scope we use the ``Dependency`` provider. The package
+container has no knowledge on where the dependencies come from. It states a need that the
+dependencies must be provided. This helps to decouple a package from the 3rd party dependencies
+and other packages.
+
+To wire the packages we use an application container. Application container has all 3rd party
+dependencies and package containers. It wires the packages and dependencies to create a
+complete application.
+
+We build an example micro application that consists of 3 packages:
+
+- ``user`` - a package with user domain logic, depends on a database
+- ``photo`` - a package with photo domain logic, depends on a database and AWS S3
+- ``analytics`` - a package with analytics domain logic, depends on the  ``user`` and ``photo``
+  package components
+
+.. image:: images/decoupled-packages.png
+    :width: 100%
+    :align: center
+
+Start from the scratch or jump to the section:
+
+.. contents::
+   :local:
+   :backlinks: none
+
+You can find the source code and instructions for running on the `Github <https://github.com/ets-labs/python-dependency-injector/tree/master/examples/miniapps/decoupled-packages>`_.
+
+Application structure
+---------------------
+
+Application consists of an ``example`` package, a configuration file and a ``requirements.txt``
+file.
+
+.. code-block:: bash
+
+   ./
+   ├── example/
+   │   ├── analytics/
+   │   │   ├── __init__.py
+   │   │   ├── containers.py
+   │   │   └── services.py
+   │   ├── photo/
+   │   │   ├── __init__.py
+   │   │   ├── containers.py
+   │   │   ├── entities.py
+   │   │   └── repositories.py
+   │   ├── user/
+   │   │   ├── __init__.py
+   │   │   ├── containers.py
+   │   │   ├── entities.py
+   │   │   └── repositories.py
+   │   ├── __init__.py
+   │   ├── __main__.py
+   │   └── containers.py
+   ├── config.ini
+   └── requirements.txt
+
+Package containers
+------------------
+
+Listing of the ``example/user/containers.py``:
+
+.. literalinclude:: ../../examples/miniapps/decoupled-packages/example/user/containers.py
+   :language: python
+
+Listing of the ``example/photo/containers.py``:
+
+.. literalinclude:: ../../examples/miniapps/decoupled-packages/example/photo/containers.py
+   :language: python
+
+Listing of the ``example/analytics/containers.py``:
+
+.. literalinclude:: ../../examples/miniapps/decoupled-packages/example/analytics/containers.py
+   :language: python
+
+Application container
+---------------------
+
+Application container consists of all packages and 3rd party dependencies. Its role is to wire
+everything together in a complete application.
+
+Listing of the ``example/containers.py``:
+
+.. literalinclude:: ../../examples/miniapps/decoupled-packages/example/containers.py
+   :language: python
+
+.. note::
+   Package ``analytics`` has dependencies on the repositories from the ``user`` and
+   ``photo`` packages. This is an example of how you can pass the dependencies from one package
+   to another.
+
+Main module
+-----------
+Listing of the ``example/__main__.py``:
+
+.. literalinclude:: ../../examples/miniapps/decoupled-packages/example/__main__.py
+   :language: python
+
+Configuration
+-------------
+
+Listing of the ``config.ini``:
+
+.. literalinclude:: ../../examples/miniapps/decoupled-packages/config.ini
+   :language: ini
+
+Run the application
+-------------------
+
+You can find the source code and instructions for running on the `Github <https://github.com/ets-labs/python-dependency-injector/tree/master/examples/miniapps/decoupled-packages>`_.
+
+.. disqus::

docs/examples/index.rst

@@ -12,5 +12,6 @@ Explore the examples to see the ``Dependency Injector`` in action.
 
     application-single-container
     application-multiple-containers
+    decoupled-packages
 
 .. disqus::

examples/miniapps/bundles/README.rst

@@ -1,8 +0,0 @@
-Dependency Injector Bundles example
-===================================
-
-Instructions for running
-
-.. code-block:: bash
-
-    python run.py

examples/miniapps/bundles/bundles/__init__.py

@@ -1 +0,0 @@
-"""Bundles package."""

examples/miniapps/bundles/bundles/photos/__init__.py

@@ -1,20 +0,0 @@
-"""Photos bundle."""
-
-from dependency_injector import containers
-from dependency_injector import providers
-
-from . import entities
-from . import repositories
-
-
-class Photos(containers.DeclarativeContainer):
-    """Photos bundle container."""
-
-    database = providers.Dependency()
-    file_storage = providers.Dependency()
-
-    photo = providers.Factory(entities.Photo)
-    photo_repository = providers.Singleton(repositories.PhotoRepository,
-                                           object_factory=photo.provider,
-                                           fs=file_storage,
-                                           db=database)

examples/miniapps/bundles/bundles/photos/entities.py

@@ -1,5 +0,0 @@
-"""Photos bundle entities module."""
-
-
-class Photo:
-    """Photo entity."""

examples/miniapps/bundles/bundles/photos/repositories.py

@@ -1,11 +0,0 @@
-"""Photos bundle entity repositories module."""
-
-
-class PhotoRepository:
-    """Photo entity repository."""
-
-    def __init__(self, object_factory, fs, db):
-        """Initialize instance."""
-        self.object_factory = object_factory
-        self.fs = fs
-        self.db = db

examples/miniapps/bundles/bundles/users/__init__.py

@@ -1,18 +0,0 @@
-"""Users bundle."""
-
-from dependency_injector import containers
-from dependency_injector import providers
-
-from . import entities
-from . import repositories
-
-
-class Users(containers.DeclarativeContainer):
-    """Users bundle container."""
-
-    database = providers.Dependency()
-
-    user = providers.Factory(entities.User)
-    user_repository = providers.Singleton(repositories.UserRepository,
-                                          object_factory=user.provider,
-                                          db=database)

examples/miniapps/bundles/bundles/users/entities.py

@@ -1,9 +0,0 @@
-"""Users bundle entities module."""
-
-
-class User:
-    """User entity."""
-
-    def __init__(self, id):
-        """Initialize instance."""
-        self.id = id

examples/miniapps/bundles/bundles/users/repositories.py

@@ -1,14 +0,0 @@
-"""Users bundle entity repositories module."""
-
-
-class UserRepository:
-    """User entity repository."""
-
-    def __init__(self, object_factory, db):
-        """Initialize instance."""
-        self.object_factory = object_factory
-        self.db = db
-
-    def get(self, id):
-        """Return user entity with given identifier."""
-        return self.object_factory(id=id)

examples/miniapps/bundles/run.py

@@ -1,40 +0,0 @@
-"""Run 'Bundles' example application."""
-
-import sqlite3
-import boto3
-
-from dependency_injector import containers
-from dependency_injector import providers
-
-from bundles.users import Users
-from bundles.photos import Photos
-
-
-class Core(containers.DeclarativeContainer):
-    """Core container."""
-
-    config = providers.Configuration('config')
-    sqlite = providers.Singleton(sqlite3.connect, config.database.dsn)
-    s3 = providers.Singleton(
-        boto3.client, 's3',
-        aws_access_key_id=config.aws.access_key_id,
-        aws_secret_access_key=config.aws.secret_access_key)
-
-
-if __name__ == '__main__':
-    # Initializing containers
-    core = Core(config={'database': {'dsn': ':memory:'},
-                        'aws': {'access_key_id': 'KEY',
-                                'secret_access_key': 'SECRET'}})
-    users = Users(database=core.sqlite)
-    photos = Photos(database=core.sqlite, file_storage=core.s3)
-
-    # Fetching few users
-    user_repository = users.user_repository()
-    user1 = user_repository.get(id=1)
-    user2 = user_repository.get(id=2)
-
-    # Making some checks
-    assert user1.id == 1
-    assert user2.id == 2
-    assert user_repository.db is core.sqlite()

examples/miniapps/decoupled-packages/README.rst

@@ -0,0 +1,29 @@
+Decoupled packages example
+==========================
+
+Create virtual env:
+
+.. code-block:: bash
+
+   python3 -m venv venv
+   . venv/bin/activate
+
+Install requirements:
+
+.. code-block:: bash
+
+   pip install -r requirements.txt
+
+Run:
+
+.. code-block:: bash
+
+   python -m example
+
+You should see:
+
+.. code-block:: bash
+
+   Retrieve user id=1, photos count=5
+   Retrieve user id=2, photos count=10
+   Aggregate analytics from user and photo bundles

examples/miniapps/decoupled-packages/config.ini

@@ -0,0 +1,6 @@
+[database]
+dsn=:memory:
+
+[aws]
+access_key_id=KEY
+secret_access_key=SECRET

examples/miniapps/decoupled-packages/example/__init__.py

@@ -0,0 +1 @@
+"""Top-level package."""

examples/miniapps/decoupled-packages/example/__main__.py

@@ -0,0 +1,24 @@
+"""Main module."""
+
+from .containers import ApplicationContainer
+
+
+if __name__ == '__main__':
+    application = ApplicationContainer()
+    application.config.from_ini('config.ini')
+
+    user_repository = application.user_package.user_repository()
+    photo_repository = application.photo_package.photo_repository()
+
+    user1 = user_repository.get(id=1)
+    user1_photos = photo_repository.get_photos(user1.id)
+    print(f'Retrieve user id={user1.id}, photos count={len(user1_photos)}')
+
+    user2 = user_repository.get(id=2)
+    user2_photos = photo_repository.get_photos(user2.id)
+    print(f'Retrieve user id={user2.id}, photos count={len(user2_photos)}')
+
+    aggregation_service = application.analytics_package.aggregation_service()
+    assert aggregation_service.user_repository is user_repository
+    assert aggregation_service.photo_repository is photo_repository
+    print('Aggregate analytics from user and photo packages')

examples/miniapps/decoupled-packages/example/analytics/__init__.py

@@ -0,0 +1 @@
+"""Analytics package."""

examples/miniapps/decoupled-packages/example/analytics/containers.py

@@ -0,0 +1,17 @@
+"""Analytics containers module."""
+
+from dependency_injector import containers, providers
+
+from . import services
+
+
+class AnalyticsContainer(containers.DeclarativeContainer):
+
+    user_repository = providers.Dependency()
+    photo_repository = providers.Dependency()
+
+    aggregation_service = providers.Singleton(
+        services.AggregationService,
+        user_repository=user_repository,
+        photo_repository=photo_repository,
+    )

examples/miniapps/decoupled-packages/example/analytics/services.py

@@ -0,0 +1,8 @@
+"""Analytics services module."""
+
+
+class AggregationService:
+
+    def __init__(self, user_repository, photo_repository):
+        self.user_repository = user_repository
+        self.photo_repository = photo_repository

examples/miniapps/decoupled-packages/example/containers.py

@@ -0,0 +1,41 @@
+"""Containers module."""
+
+import sqlite3
+
+import boto3
+from dependency_injector import containers, providers
+
+from .user.containers import UserContainer
+from .photo.containers import PhotoContainer
+from .analytics.containers import AnalyticsContainer
+
+
+class ApplicationContainer(containers.DeclarativeContainer):
+
+    config = providers.Configuration()
+
+    sqlite = providers.Singleton(sqlite3.connect, config.database.dsn)
+
+    s3 = providers.Singleton(
+        boto3.client,
+        service_name='s3',
+        aws_access_key_id=config.aws.access_key_id,
+        aws_secret_access_key=config.aws.secret_access_key,
+    )
+
+    user_package = providers.Container(
+        UserContainer,
+        database=sqlite,
+    )
+
+    photo_package = providers.Container(
+        PhotoContainer,
+        database=sqlite,
+        file_storage=s3,
+    )
+
+    analytics_package = providers.Container(
+        AnalyticsContainer,
+        user_repository=user_package.user_repository,
+        photo_repository=photo_package.photo_repository,
+    )

examples/miniapps/decoupled-packages/example/photo/__init__.py

@@ -0,0 +1 @@
+"""Photo package."""

examples/miniapps/decoupled-packages/example/photo/containers.py

@@ -0,0 +1,20 @@
+"""Photo containers module."""
+
+from dependency_injector import containers, providers
+
+from . import entities, repositories
+
+
+class PhotoContainer(containers.DeclarativeContainer):
+
+    database = providers.Dependency()
+    file_storage = providers.Dependency()
+
+    photo = providers.Factory(entities.Photo)
+
+    photo_repository = providers.Singleton(
+        repositories.PhotoRepository,
+        entity_factory=photo.provider,
+        fs=file_storage,
+        db=database,
+    )

examples/miniapps/decoupled-packages/example/photo/entities.py

@@ -0,0 +1,5 @@
+"""Photo entities module."""
+
+
+class Photo:
+    ...

examples/miniapps/decoupled-packages/example/photo/repositories.py

@@ -0,0 +1,12 @@
+"""Photo repositories module."""
+
+
+class PhotoRepository:
+
+    def __init__(self, entity_factory, fs, db):
+        self.entity_factory = entity_factory
+        self.fs = fs
+        self.db = db
+
+    def get_photos(self, user_id):
+        return [self.entity_factory() for _ in range(user_id*5)]

examples/miniapps/decoupled-packages/example/user/__init__.py

@@ -0,0 +1 @@
+"""User package."""

examples/miniapps/decoupled-packages/example/user/containers.py

@@ -0,0 +1,18 @@
+"""User containers module."""
+
+from dependency_injector import containers, providers
+
+from . import entities, repositories
+
+
+class UserContainer(containers.DeclarativeContainer):
+
+    database = providers.Dependency()
+
+    user = providers.Factory(entities.User)
+
+    user_repository = providers.Singleton(
+        repositories.UserRepository,
+        entity_factory=user.provider,
+        db=database,
+    )

examples/miniapps/decoupled-packages/example/user/entities.py

@@ -0,0 +1,7 @@
+"""User entities module."""
+
+
+class User:
+
+    def __init__(self, id):
+        self.id = id

examples/miniapps/decoupled-packages/example/user/repositories.py

@@ -0,0 +1,11 @@
+"""User repositories module."""
+
+
+class UserRepository:
+
+    def __init__(self, entity_factory, db):
+        self.entity_factory = entity_factory
+        self.db = db
+
+    def get(self, id):
+        return self.entity_factory(id=id)

examples/miniapps/decoupled-packages/requirements.txt

@@ -0,0 +1,2 @@
+dependency-injector
+boto3

src/dependency_injector/providers.pyi

@@ -59,7 +59,7 @@ class Delegate(Provider):
 
 
 class Dependency(Provider, Generic[T]):
-    def __init__(self, instance_of: Type[T]) -> None: ...
+    def __init__(self, instance_of: Type[T] = object) -> None: ...
     def __call__(self, *args: Injection, **kwargs: Injection) -> T: ...
     @property
     def provided(self) -> ProvidedInstance: ...