Add bundles example miniapp

Author: rmk135

docs/examples/bundles_miniapp.rst

@@ -0,0 +1,77 @@
+Bundles mini application example
+--------------------------------
+
+.. currentmodule:: dependency_injector.containers
+
+"Bundles" is an example mini application that is intented 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 ``bundeles/users/__init__.py``:
+
+.. literalinclude:: ../../examples/miniapps/bundles/bundles/users/__init__.py
+   :language: python
+   :linenos:
+
+.. note::
+
+    - ``Users`` container has dependency on database.
+
+Listing of ``bundeles/photos/__init__.py``:
+
+.. literalinclude:: ../../examples/miniapps/bundles/bundles/photos/__init__.py
+   :language: python
+   :linenos:
+
+.. 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
+   :linenos:
+
+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/index.rst

@@ -17,3 +17,4 @@ and powered by *Dependency Injector* framework.
 
     movie_lister
     services_miniapp
+    bundles_miniapp

docs/main/changelog.rst

@@ -20,6 +20,7 @@ Development version
 - Add method to dynamic catalog for overriding groups of providers -  
   ``DynamicContainer.set_providers(**overriding_providers)``.
 - Fix bug when copying ``Configuration`` provider.
+- Add "bundles" example miniapp.
 
 
 3.8.2

examples/miniapps/bundles/run.py

@@ -1,4 +1,7 @@
-"""Example application - Bundles."""
+"""Run 'Bundles' example application."""
+
+import sqlite3
+import boto3
 
 from dependency_injector import containers
 from dependency_injector import providers
@@ -10,15 +13,22 @@
 class Core(containers.DeclarativeContainer):
     """Core container."""
 
-    pgsql = providers.Singleton(object)
-    s3 = providers.Singleton(object)
+    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()
-    users = Users(database=core.pgsql)
-    photos = Photos(database=core.pgsql, file_storage=core.s3)
+    core.config.update({'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()
@@ -28,4 +38,4 @@ class Core(containers.DeclarativeContainer):
     # Making some checks
     assert user1.id == 1
     assert user2.id == 2
-    assert user_repository.db is core.pgsql()
+    assert user_repository.db is core.sqlite()