Refactor factory of factories pattern example

docs/examples-other/chained-factories.rst

@@ -13,7 +13,7 @@ additional arguments.
        base_argument=1,
    )
 
-   factory = providers.Factory(
+   concrete_factory = providers.Factory(
        base_factory,
        extra_argument=2,
    )
@@ -23,7 +23,6 @@ additional arguments.
        instance = concrete_factory()
        # Same as: # instance = SomeClass(base_argument=1, extra_argument=2)
 
-
 Sample code
 -----------
 
@@ -37,8 +36,6 @@ Arguments priority
 
 Passing of the arguments works the same way like for any other :ref:`factory-provider`.
 
-Explanation & some more examples:
-
 .. code-block:: python
 
    # 1. Keyword arguments of upper level factory are added to lower level factory
@@ -55,7 +52,7 @@ Explanation & some more examples:
    )
    print(chained_dict_factory())  # prints: {'arg1': 2}
 
-   # 3. Keyword arguments provided from context have most priority
+   # 3. Keyword arguments provided from context have the most priority
    chained_dict_factory = providers.Factory(
        providers.Factory(dict, arg1=1),
        arg1=2,

docs/examples-other/factory-of-factories.rst

@@ -0,0 +1,74 @@
+Factory of Factories pattern
+============================
+
+This example demonstrates "Factory of Factories" pattern.
+
+The idea of the pattern is in creating a ``Factory`` that creates another ``Factory`` and adds
+additional arguments.
+
+.. code-block:: python
+
+   base_factory = providers.Factory(
+       providers.Factory
+       SomeClass,
+       base_argument=1,
+   )
+
+   concrete_factory = providers.Factory(
+       OtherClass,
+       instance=base_factory(extra_argument=1),
+   )
+
+
+   if __name__ == '__main__':
+       instance = concrete_factory()
+       # Same as: # instance = SomeClass(base_argument=1, extra_argument=2)
+
+Sample code
+-----------
+
+Listing of the pattern example:
+
+.. literalinclude:: ../../examples/miniapps/factory-patterns/factory_of_factories.py
+   :language: python
+
+Arguments priority
+------------------
+
+Passing of the arguments works the same way like for any other :ref:`factory-provider`.
+
+.. code-block:: python
+
+   # 1. Keyword arguments of upper level factory are added to lower level factory
+   factory_of_dict_factories = providers.Factory(
+       providers.Factory,
+       dict,
+       arg1=1,
+   )
+   dict_factory = factory_of_dict_factories(arg2=2)
+   print(dict_factory())  # prints: {'arg1': 1, 'arg2': 2}
+
+   # 2. Keyword arguments of upper level factory have priority
+   factory_of_dict_factories = providers.Factory(
+       providers.Factory,
+       dict,
+       arg1=1,
+   )
+   dict_factory = factory_of_dict_factories(arg1=2)
+   print(dict_factory())  # prints: {'arg1': 2}
+
+   # 3. Keyword arguments provided from context have the most priority
+   factory_of_dict_factories = providers.Factory(
+       providers.Factory,
+       dict,
+       arg1=1,
+   )
+   dict_factory = factory_of_dict_factories(arg1=2)
+   print(dict_factory(arg1=3))  # prints: {'arg1': 3}
+
+Credits
+-------
+
+The "Factory of Factories" pattern was suggested by the ``Dependency Injector`` users.
+
+.. disqus::

docs/examples-other/factory_of_factories.rst

@@ -1,20 +0,0 @@
-Factory of Factories pattern
-============================
-
-This example demonstrate implementation of "Factory of Factories" pattern.
-Main idea of this pattern is about creation of a :py:class:`Factory` that
-creates another :py:class:`Factory` and mix additional arguments to it.
-
-Listing of ``data.py``, demonstrates sample classes structure:
-
-.. literalinclude:: ../../examples/miniapps/factory_patterns/data.py
-   :language: python
-
-Listing of ``factory_of_factories.py``, demonstrates "Chained Factories"
-pattern and provide some explanation:
-
-.. literalinclude:: ../../examples/miniapps/factory_patterns/factory_of_factories.py
-   :language: python
-
-
-.. disqus::

docs/examples-other/index.rst

@@ -14,4 +14,4 @@ This sections contains assorted ``Dependency Injector`` examples.
     use-cases
     password-hashing
     chained-factories
-    factory_of_factories
+    factory-of-factories

docs/examples-other/password-hashing.rst

@@ -10,11 +10,17 @@ This example demonstrates an injection of the ``Callable`` provider.
 
 The source code is available on the `Github <https://github.com/ets-labs/python-dependency-injector/tree/master/examples/miniapps/password-hashing>`_.
 
-Listing of the ``example.py``:
+Sample code
+-----------
+
+Listing of the pattern example:
 
 .. literalinclude:: ../../examples/miniapps/password-hashing/example.py
    :language: python
 
+Run the example
+---------------
+
 Instructions for running:
 
 .. code-block:: bash

docs/main/changelog.rst

@@ -12,6 +12,7 @@ Develop
 - Refactor "use cases" example.
 - Refactor "password hashing" example.
 - Refactor "chained factories" pattern example.
+- Refactor "factory of factories" pattern example.
 - Fix declarative container mypy stub to ``__init__`` to accept not only providers.
 - Refactor main module of the "decoupled packages" example.
 

examples/miniapps/factory-patterns/data.py

@@ -1,35 +0,0 @@
-"""Sample classes and objects."""
-
-
-class SqlAlchemyDatabaseService:
-
-    def __init__(self, session, base_class):
-        self.session = session
-        self.base_class = base_class
-
-
-class TokensService:
-
-    def __init__(self, id_generator, database):
-        self.id_generator = id_generator
-        self.database = database
-
-
-class Token:
-    ...
-
-
-class UsersService:
-
-    def __init__(self, id_generator, database):
-        self.id_generator = id_generator
-        self.database = database
-
-
-class User:
-    ...
-
-
-# Sample objects
-session = object()
-id_generator = object()

examples/miniapps/factory-patterns/factory_of_factories.py

@@ -1,69 +1,68 @@
 """`Factory of Factories` pattern."""
 
-from dependency_injector import providers
-
-from data import (
-    id_generator,
-    session,
-    SqlAlchemyDatabaseService,
-    TokensService,
-    Token,
-    UsersService,
-    User,
-)
+from dependency_injector import containers, providers
 
 
-# "Factory of Factories" pattern
+class SqlAlchemyDatabaseService:
 
-database_factory = providers.Factory(
-    providers.Factory,
-    SqlAlchemyDatabaseService,
-    session=session,
-)
+    def __init__(self, session, base_class):
+        self.session = session
+        self.base_class = base_class
 
-tokens = providers.Factory(
-    TokensService,
-    id_generator=id_generator,
-    database=database_factory(base_class=Token),
-)
 
-users = providers.Factory(
-    UsersService,
-    id_generator=id_generator,
-    database=database_factory(base_class=User),
-)
+class TokensService:
 
-tokens_service = tokens()
-assert tokens_service.database.base_class is Token
+    def __init__(self, id_generator, database):
+        self.id_generator = id_generator
+        self.database = database
 
-users_service = users()
-assert users_service.database.base_class is User
 
-# Explanation & some more examples
+class Token:
+    ...
 
-# 1. Keyword arguments of upper level factory are added to lower level factory
-factory_of_dict_factories = providers.Factory(
-    providers.Factory,
-    dict,
-    arg1=1,
-)
-dict_factory = factory_of_dict_factories(arg2=2)
-print(dict_factory())  # prints: {'arg1': 1, 'arg2': 2}
 
-# 2. Keyword arguments of upper level factory have priority
-factory_of_dict_factories = providers.Factory(
-    providers.Factory,
-    dict,
-    arg1=1,
-)
-dict_factory = factory_of_dict_factories(arg1=2)
-print(dict_factory())  # prints: {'arg1': 2}
+class UsersService:
 
-# 3. Keyword arguments provided from context have most priority
-factory_of_dict_factories = providers.Factory(
-    providers.Factory,
-    dict,
-    arg1=1,
-)
-dict_factory = factory_of_dict_factories(arg1=2)
-print(dict_factory(arg1=3))  # prints: {'arg1': 3}
+    def __init__(self, id_generator, database):
+        self.id_generator = id_generator
+        self.database = database
+
+
+class User:
+    ...
+
+
+# Sample objects
+session = object()
+id_generator = object()
+
+
+class Container(containers.DeclarativeContainer):
+
+    database_factory = providers.Factory(
+        providers.Factory,
+        SqlAlchemyDatabaseService,
+        session=session,
+    )
+
+    token_service = providers.Factory(
+        TokensService,
+        id_generator=id_generator,
+        database=database_factory(base_class=Token),
+    )
+
+    user_service = providers.Factory(
+        UsersService,
+        id_generator=id_generator,
+        database=database_factory(base_class=User),
+    )
+
+
+if __name__ == '__main__':
+    container = Container()
+
+    token_service = container.token_service()
+    assert token_service.database.base_class is Token
+
+    user_service = container.user_service()
+    assert user_service.database.base_class is User