Edit configuration provider docs

docs/main/changelog.rst

@@ -10,7 +10,7 @@ follows `Semantic versioning`_
 Development version
 -------------------
 - Update documentation and rework examples for: ``Singleton``, ``Callable``, ``Coroutine``,
-  ``Object``, ``List`` providers.
+  ``Object``, ``List``, ``Configuration`` providers.
 
 3.34.0
 ------

docs/providers/configuration.rst

@@ -1,5 +1,12 @@
-Configuration providers
------------------------
+Configuration provider
+----------------------
+
+.. meta::
+   :keywords: Python,DI,Dependency injection,IoC,Inversion of Control,Configuration,Injection,
+              Option,Ini,Json,Yaml,Dict,Environment Variable,Load,Read,Get
+   :description: Configuration provides configuration options to the other providers. This page
+                 demonstrates how to use Configuration provider to inject the dependencies, load
+                 a configuration from an ini or yaml file, dictionary or an environment variable.
 
 .. currentmodule:: dependency_injector.providers
 
@@ -10,13 +17,13 @@ Configuration providers
    :emphasize-lines: 4,9-10
    :lines: 4-14
 
-It implements "use first, define later" principle.
+It implements the principle "use first, define later".
 
-Loading from ``ini`` file
-~~~~~~~~~~~~~~~~~~~~~~~~~
+Loading from an INI file
+~~~~~~~~~~~~~~~~~~~~~~~~
 
-:py:class:`Configuration` provider can load configuration from ``ini`` file using
-:py:meth:`Configuration.from_ini`:
+``Configuration`` provider can load configuration from an ``ini`` file using the
+:py:meth:`Configuration.from_ini` method:
 
 .. literalinclude:: ../../examples/providers/configuration/configuration_ini.py
    :language: python
@@ -28,15 +35,15 @@ where ``examples/providers/configuration/config.ini`` is:
 .. literalinclude:: ../../examples/providers/configuration/config.ini
    :language: ini
 
-:py:meth:`Configuration.from_ini` supports environment variables interpolation. Use
-``${ENV_NAME}`` format in the configuration file to substitute value of environment
+:py:meth:`Configuration.from_ini` method supports environment variables interpolation. Use
+``${ENV_NAME}`` format in the configuration file to substitute value of the environment
 variable ``ENV_NAME``.
 
-Loading from ``yaml`` file
-~~~~~~~~~~~~~~~~~~~~~~~~~~
+Loading from a YAML file
+~~~~~~~~~~~~~~~~~~~~~~~~
 
-:py:class:`Configuration` provider can load configuration from ``yaml`` file using
-:py:meth:`Configuration.from_yaml`:
+``Configuration`` provider can load configuration from a ``yaml`` file using the
+:py:meth:`Configuration.from_yaml` method:
 
 .. literalinclude:: ../../examples/providers/configuration/configuration_yaml.py
    :language: python
@@ -48,43 +55,51 @@ where ``examples/providers/configuration/config.yml`` is:
 .. literalinclude:: ../../examples/providers/configuration/config.yml
    :language: ini
 
-:py:meth:`Configuration.from_yaml` supports environment variables interpolation. Use
-``${ENV_NAME}`` format in the configuration file to substitute value of environment
+:py:meth:`Configuration.from_yaml` method supports environment variables interpolation. Use
+``${ENV_NAME}`` format in the configuration file to substitute value of the environment
 variable ``ENV_NAME``.
 
 .. note::
 
-    Loading configuration from yaml requires ``PyYAML`` package. You can install
-    `Dependency Injector` with extras ``pip install dependency-injector[yaml]`` or install
-    ``PyYAML`` separately  ``pip install pyyaml``.
+   Loading of a yaml configuration requires ``PyYAML`` package.
 
-Loading from ``dict``
-~~~~~~~~~~~~~~~~~~~~~
+   You can install the ``Dependency Injector`` with an extra dependency::
 
-:py:class:`Configuration` provider can load configuration from Python ``dict`` using
-:py:meth:`Configuration.from_dict`:
+      pip install dependency-injector[yaml]
+
+   or install ``PyYAML`` directly::
+
+      pip install pyyaml
+
+   *Don't forget to mirror the changes in the requirements file.*
+
+Loading from a dictionary
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+``Configuration`` provider can load configuration from a Python ``dict`` using the
+:py:meth:`Configuration.from_dict` method:
 
 .. literalinclude:: ../../examples/providers/configuration/configuration_dict.py
    :language: python
    :lines: 3-5,6-
    :emphasize-lines: 6-13
 
-Loading from environment variable
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Loading from an environment variable
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-:py:class:`Configuration` provider can load configuration from environment variable using
-:py:meth:`Configuration.from_env`:
+``Configuration`` provider can load configuration from an environment variable using the
+:py:meth:`Configuration.from_env` method:
 
 .. literalinclude:: ../../examples/providers/configuration/configuration_env.py
    :language: python
    :lines: 5-7,13-21
    :emphasize-lines: 6-8
 
-Loading from multiple sources
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Loading from the multiple sources
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-:py:class:`Configuration` provider can load configuration from multiple sources. Loaded
-configuration is merged recursively over existing configuration.
+``Configuration`` provider can load configuration from the multiple sources. Loaded
+configuration is merged recursively over the existing configuration.
 
 .. literalinclude:: ../../examples/providers/configuration/configuration_multiple.py
    :language: python
@@ -96,12 +111,12 @@ where ``examples/providers/configuration/config.local.yml`` is:
 .. literalinclude:: ../../examples/providers/configuration/config.local.yml
    :language: ini
 
-Specifying value type
-~~~~~~~~~~~~~~~~~~~~~
+Specifying the value type
+~~~~~~~~~~~~~~~~~~~~~~~~~
 
 You can specify the type of the injected configuration value explicitly.
 
-This helps when you read the value from the ini file or the environment variable and need to
+This helps when you read the value from an ini file or an environment variable and need to
 convert it into an ``int`` or a ``float``.
 
 .. literalinclude:: ../../examples/providers/configuration/configuration_type.py
@@ -109,20 +124,20 @@ convert it into an ``int`` or a ``float``.
    :lines: 3-
    :emphasize-lines: 17
 
-:py:class:`Configuration` provider has next helper methods:
+``Configuration`` provider has next helper methods:
 
 - ``.as_int()``
 - ``.as_float()``
 - ``.as_(callback, *args, **kwargs)``
 
-The last method ``.as_(callback, *args, **kwargs)`` helps to implement a other conversions.
+The last method ``.as_(callback, *args, **kwargs)`` helps to implement other conversions.
 
 .. literalinclude:: ../../examples/providers/configuration/configuration_type_custom.py
    :language: python
    :lines: 3-
    :emphasize-lines: 16
 
-With the ``.as_(callback, *args, **kwargs)`` you can specify the function that will be called
+With the ``.as_(callback, *args, **kwargs)`` you can specify a function that will be called
 before the injection. The value from the config will be passed as a first argument. The returned
 value will be injected. Parameters ``*args`` and ``**kwargs`` are handled as any other injections.