python-dependency-injector/docs/index.rst

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Dependency Injector --- Dependency injection framework for Python
=================================================================
.. meta::
:google-site-verification: V1hlKfpgL3AARAElwFcqP4qW1Smsx5bKSRU8O86i20Y
:keywords: Python,Dependency injection,DI,Inversion of Control,IoC,
IoC Container,Factory, Singleton, Design Patterns
:description: Dependency Injector is a dependency injection framework
for Python. It helps to maintain you application structure.
It was designed to be unified, developer-friendly
tool that helps to implement dependency injection design
pattern in formal, pretty, Pythonic way. Dependency Injector
provides implementations of such popular design patterns
like IoC container, Factory and Singleton. Dependency
Injector providers are implemented as C extension types
using Cython.
.. _index:
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:alt: Latest Version
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:alt: License
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:alt: Supported Python versions
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:target: https://pypi.org/project/dependency-injector/
:alt: Supported Python implementations
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:alt: Downloads
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:alt: Coverage Status
``Dependency Injector`` is a dependency injection framework for Python.
It helps implementing the dependency injection principle.
Key features of the ``Dependency Injector``:
- **Providers**. Provides ``Factory``, ``Singleton``, ``Callable``, ``Coroutine``, ``Object``,
``List``, ``Dict``, ``Configuration``, ``Resource``, ``Dependency`` and ``Selector`` providers
that help assembling your objects. See :ref:`providers`.
- **Overriding**. Can override any provider by another provider on the fly. This helps in testing
and configuring dev / stage environment to replace API clients with stubs etc. See
:ref:`provider-overriding`.
- **Configuration**. Reads configuration from ``yaml`` & ``ini`` files, environment variables
and dictionaries. See :ref:`configuration-provider`.
- **Resources**. Helps with initialization and configuring of logging, event loop, thread
or process pool, etc. Can be used for per-function execution scope in tandem with wiring.
See :ref:`resource-provider`.
- **Containers**. Provides declarative and dynamic containers. See :ref:`containers`.
- **Wiring**. Injects dependencies into functions and methods. Helps integrating with
other frameworks: Django, Flask, Aiohttp, Sanic, FastAPI, etc. See :ref:`wiring`.
- **Typing**. Provides typing stubs, ``mypy``-friendly. See :ref:`provider-typing`.
- **Performance**. Fast. Written in ``Cython``.
- **Maturity**. Mature and production-ready. Well-tested, documented and supported.
.. code-block:: python
from dependency_injector import containers, providers
from dependency_injector.wiring import inject, Provide
class Container(containers.DeclarativeContainer):
config = providers.Configuration()
api_client = providers.Singleton(
ApiClient,
api_key=config.api_key,
timeout=config.timeout.as_int(),
)
service = providers.Factory(
Service,
api_client=api_client,
)
@inject
def main(service: Service = Provide[Container.service]):
...
if __name__ == '__main__':
container = Container()
container.config.api_key.from_env('API_KEY')
container.config.timeout.from_env('TIMEOUT')
container.wire(modules=[sys.modules[__name__]])
main() # <-- dependency is injected automatically
with container.api_client.override(mock.Mock()):
main() # <-- overridden dependency is injected automatically
With the ``Dependency Injector`` objects assembling is consolidated in the container.
Dependency injections are defined explicitly.
This makes easier to understand and change how application works.
.. figure:: https://raw.githubusercontent.com/wiki/ets-labs/python-dependency-injector/img/di-readme.svg
:target: https://github.com/ets-labs/python-dependency-injector
Explore the documentation to know more about the ``Dependency Injector``.
.. _contents:
Contents
--------
.. toctree::
:maxdepth: 2
introduction/index
examples/index
tutorials/index
providers/index
containers/index
wiring
examples-other/index
api/index
main/feedback
main/changelog