python-dependency-injector/docs/providers/index.rst
Roman Mogylatov d8439a28b1
Make provider generic type (#293)
* Add __class_getitem__ for Provider to null the typing in runtime

* Make Provider stub generic and remove types module

* Update types module tests

* Return types module with deprecation warning

* Return types module with deprecation warning

* Update changelog

* Add docs page
2020-09-13 20:32:21 -04:00

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.. _providers:
Providers
=========
Providers help to assemble the objects. They create objects and inject the dependencies.
Each provider is a callable. You call the provider like a function when you need to create an
object. Provider retrieves the underlying dependencies and inject them into the created object.
It causes the cascade effect that helps to assemble object graphs. See ``Factory``, ``Singleton``,
``Callable`` and other provider docs below.
.. code-block:: bash
provider1()
├──> provider2()
├──> provider3()
│ │
│ └──> provider4()
└──> provider5()
└──> provider6()
Another providers feature is an overriding. You can override any provider with another provider.
This helps in testing. This also helps in overriding API clients with stubs for the development
or staging environment. See the example at :ref:`provider-overriding`.
If you need to inject not the whole object but the parts see :ref:`provided-instance`.
To create a new provider see :ref:`create-provider`.
Providers module API docs - :py:mod:`dependency_injector.providers`
.. toctree::
:maxdepth: 2
factory
singleton
callable
coroutine
object
list
configuration
selector
dependency
overriding
provided_instance
custom
typing_mypy