Update the declarative container docs

docs/containers/declarative.rst

@@ -3,53 +3,42 @@ Declarative containers
 
 .. currentmodule:: dependency_injector.containers
 
-:py:class:`DeclarativeContainer` is inversion of control container that 
-could be defined in declarative manner. It should cover most of the cases 
-when list of providers that would be included in container is deterministic 
-(container will not change its structure in runtime).
+:py:class:`DeclarativeContainer` is a collection of the providers defined in the declarative
+manner. It covers the use cases when your application structure does not change in the runtime.
 
-Declarative containers have to extend base declarative container class - 
-:py:class:`dependency_injector.containers.DeclarativeContainer`.
-
-Declarative container's providers have to be defined like container's class 
-attributes. Every provider in container has name. This name should follow 
-``some_provider`` convention, that is standard naming convention for 
-attribute names in Python.
-
-.. note::
-
-    Declarative containers have several features that could be useful 
-    for some kind of operations on container's providers, please visit API 
-    documentation for getting full list of features - 
-    :py:class:`dependency_injector.containers.DeclarativeContainer`.
-
-Here is an simple example of defining declarative container with several 
-factories:
-
-.. image:: /images/containers/declarative.png
-    :width: 85%
-    :align: center
+Container has the ``.providers`` attribute. It is a dictionary of the container providers.
 
 .. literalinclude:: ../../examples/containers/declarative.py
    :language: python
+   :lines: 3-
 
-Example of declarative containers inheritance:
+Your declarative container has to extend base declarative container class -
+:py:class:`dependency_injector.containers.DeclarativeContainer`.
 
-.. image:: /images/containers/declarative_inheritance.png
-    :width: 100%
-    :align: center
+Declarative container classes can not have any methods or any other attributes then providers.
+
+The declarative container providers should only be used after the container is initialized.
+
+The container class provides next attributes:
+
+- ``providers`` - the dictionary of all the container providers
+- ``cls_providers`` - the dictionary of the container providers of the current container
+- ``inherited_providers`` - the dictionary of all the inherited container providers
 
 .. literalinclude:: ../../examples/containers/declarative_inheritance.py
    :language: python
+   :lines: 3-
 
-Example of declarative containers's provider injections:
-
-.. image:: /images/containers/declarative_injections.png
-    :width: 100%
-    :align: center
+Injections in the declarative container are done the usual way:
 
 .. literalinclude:: ../../examples/containers/declarative_injections.py
    :language: python
+   :lines: 3-
 
+You can override the container providers when you create the container instance:
+
+.. literalinclude:: ../../examples/containers/declarative_override_providers.py
+   :language: python
+   :lines: 3-
 
 .. disqus::

docs/containers/index.rst

@@ -1,21 +1,16 @@
-IoC Containers
-==============
+Containers
+==========
 
-Containers are collections of providers. Main purpose of containers is to group
-providers. 
+Containers are collections of the providers.
 
-There are, actually, several popular cases of containers usage:
+There are several use cases how you can use containers:
 
-+ Keeping all providers in a single container.
-+ Grouping of providers from the same architectural layer (for example, 
++ Keeping all the providers in a single container (most common).
++ Grouping of the providers from the same architectural layer (for example,
   ``Services``, ``Models`` and ``Forms`` containers).
 + Grouping of providers from the same functional groups (for example,
-  container ``Users``, that contains all functional parts of ``Users``
-  component).
-
-Also, for both of these and some other cases, it might be useful to attach 
-some init / shutdown functionality or something else, that deals with group 
-of providers.
+  container ``Users``, that contains all functional parts of the ``users``
+  package).
 
 Containers package API docs - :py:mod:`dependency_injector.containers`.
 

examples/containers/declarative.py

@@ -1,23 +1,22 @@
-"""Declarative IoC container simple example."""
+"""Declarative container example."""
 
-import dependency_injector.containers as containers
-import dependency_injector.providers as providers
+from dependency_injector import containers, providers
 
 
-# Defining declarative IoC container:
 class Container(containers.DeclarativeContainer):
-    """Example IoC container."""
 
     factory1 = providers.Factory(object)
 
     factory2 = providers.Factory(object)
 
 
-# Creating some objects:
-object1 = Container.factory1()
-object2 = Container.factory2()
+container = Container()
 
-# Making some asserts:
-assert object1 is not object2
-assert isinstance(object1, object)
-assert isinstance(object2, object)
+object1 = container.factory1()
+object2 = container.factory2()
+
+print(container.providers)
+# {
+#     'factory1': <dependency_injector.providers.Factory(...),
+#     'factory2': <dependency_injector.providers.Factory(...),
+# }

examples/containers/declarative_inheritance.py

@@ -1,30 +1,34 @@
-"""Declarative IoC containers inheritance example."""
+"""Declarative containers inheritance example."""
 
-import dependency_injector.containers as containers
-import dependency_injector.providers as providers
+from dependency_injector import containers, providers
 
 
 class ContainerA(containers.DeclarativeContainer):
-    """Example IoC container A."""
 
     provider1 = providers.Factory(object)
 
 
 class ContainerB(ContainerA):
-    """Example IoC container B."""
 
     provider2 = providers.Singleton(object)
 
 
-# Making some asserts for `providers` attribute:
-assert ContainerA.providers == dict(provider1=ContainerA.provider1)
-assert ContainerB.providers == dict(provider1=ContainerA.provider1,
-                                    provider2=ContainerB.provider2)
+assert ContainerA.providers == {
+    'provider1': ContainerA.provider1,
+}
+assert ContainerB.providers == {
+    'provider1': ContainerA.provider1,
+    'provider2': ContainerB.provider2,
+}
 
-# Making some asserts for `cls_providers` attribute:
-assert ContainerA.cls_providers == dict(provider1=ContainerA.provider1)
-assert ContainerB.cls_providers == dict(provider2=ContainerB.provider2)
+assert ContainerA.cls_providers == {
+    'provider1': ContainerA.provider1,
+}
+assert ContainerB.cls_providers == {
+    'provider2': ContainerB.provider2,
+}
 
-# Making some asserts for `inherited_providers` attribute:
-assert ContainerA.inherited_providers == dict()
-assert ContainerB.inherited_providers == dict(provider1=ContainerB.provider1)
+assert ContainerA.inherited_providers == {}
+assert ContainerB.inherited_providers == {
+    'provider1': ContainerA.provider1,
+}

examples/containers/declarative_injections.py

@@ -1,35 +1,41 @@
-"""Declarative IoC container's provider injections example."""
+"""Declarative container injections example."""
 
 import sqlite3
-import collections
 
-import dependency_injector.containers as containers
-import dependency_injector.providers as providers
+from dependency_injector import containers, providers
 
 
-UsersService = collections.namedtuple('UsersService', ['db'])
-AuthService = collections.namedtuple('AuthService', ['db', 'users_service'])
+class UserService:
+    def __init__(self, db: sqlite3.Connection):
+        self.db = db
 
 
-class Services(containers.DeclarativeContainer):
-    """IoC container of service providers."""
+class AuthService:
+    def __init__(self, db: sqlite3.Connection, user_service: UserService):
+        self.db = db
+        self.user_service = user_service
+
+
+class Container(containers.DeclarativeContainer):
 
     database = providers.Singleton(sqlite3.connect, ':memory:')
 
-    users = providers.Factory(UsersService,
-                              db=database)
+    user_service = providers.Factory(
+        UserService,
+        db=database,
+    )
 
-    auth = providers.Factory(AuthService,
-                             db=database,
-                             users_service=users)
+    auth_service = providers.Factory(
+        AuthService,
+        db=database,
+        user_service=user_service,
+    )
 
 
-# Retrieving service providers from container:
-users_service = Services.users()
-auth_service = Services.auth()
+container = Container()
 
-# Making some asserts:
-assert users_service.db is auth_service.db is Services.database()
-assert isinstance(auth_service.users_service, UsersService)
-assert users_service is not Services.users()
-assert auth_service is not Services.auth()
+user_service = container.user_service()
+auth_service = container.auth_service()
+
+assert user_service.db is auth_service.db is container.database()
+assert isinstance(auth_service.user_service, UserService)

examples/containers/declarative_override_providers.py

@@ -0,0 +1,17 @@
+"""Declarative container provider override example."""
+
+import sqlite3
+from unittest import mock
+
+from dependency_injector import containers, providers
+
+
+class Container(containers.DeclarativeContainer):
+
+    database = providers.Singleton(sqlite3.connect, ':memory:')
+
+
+container = Container(database=mock.Mock(sqlite3.Connection))
+
+database = container.database()
+assert isinstance(database, mock.Mock)