.. figure:: https://raw.githubusercontent.com/wiki/ets-labs/python-dependency-injector/img/logo.svg :target: https://github.com/ets-labs/python-dependency-injector | .. image:: https://img.shields.io/pypi/v/dependency_injector.svg :target: https://pypi.org/project/dependency-injector/ :alt: Latest Version .. image:: https://img.shields.io/pypi/l/dependency_injector.svg :target: https://pypi.org/project/dependency-injector/ :alt: License .. image:: https://img.shields.io/pypi/pyversions/dependency_injector.svg :target: https://pypi.org/project/dependency-injector/ :alt: Supported Python versions .. image:: https://img.shields.io/pypi/implementation/dependency_injector.svg :target: https://pypi.org/project/dependency-injector/ :alt: Supported Python implementations .. image:: https://pepy.tech/badge/dependency-injector :target: https://pepy.tech/project/dependency-injector :alt: Downloads .. image:: https://pepy.tech/badge/dependency-injector/month :target: https://pepy.tech/project/dependency-injector :alt: Downloads .. image:: https://pepy.tech/badge/dependency-injector/week :target: https://pepy.tech/project/dependency-injector :alt: Downloads .. image:: https://img.shields.io/pypi/wheel/dependency-injector.svg :target: https://pypi.org/project/dependency-injector/ :alt: Wheel .. image:: https://travis-ci.org/ets-labs/python-dependency-injector.svg?branch=master :target: https://travis-ci.org/ets-labs/python-dependency-injector :alt: Build Status .. image:: http://readthedocs.org/projects/python-dependency-injector/badge/?version=latest :target: http://python-dependency-injector.ets-labs.org/ :alt: Docs Status .. image:: https://coveralls.io/repos/github/ets-labs/python-dependency-injector/badge.svg?branch=master :target: https://coveralls.io/github/ets-labs/python-dependency-injector?branch=master :alt: Coverage Status What is ``Dependency Injector``? ================================ ``Dependency Injector`` is a dependency injection framework for Python. It stands on two principles: - Explicit is better than implicit (PEP20). - Do no magic to your code. How does it different from the other frameworks? - **No autowiring.** The framework does NOT do any autowiring / autoresolving of the dependencies. You need to specify everything explicitly. Because *"Explicit is better than implicit" (PEP20)*. - **Does not pollute your code.** Your application does NOT know and does NOT depend on the framework. No ``@inject`` decorators, annotations, patching or any other magic tricks. ``Dependency Injector`` makes a simple contract with you: - You tell the framework how to build you code - The framework does it for you The power of the ``Dependency Injector`` is in its simplicity and straightforwardness. It is a simple tool for the powerful concept. Example ======= With the ``Dependency Injector`` you keep **application structure in one place**. This place is called **the container**. You use the container to manage all the components of the application. All the component dependencies are defined explicitly. This provides the control on the application structure. It is **easy to understand and change** it. .. figure:: https://raw.githubusercontent.com/wiki/ets-labs/python-dependency-injector/img/di-map.svg :target: https://github.com/ets-labs/python-dependency-injector *The container is like a map of your application. You always know what depends on what.* Example application container: .. code-block:: python import logging import sys from dependency_injector import containers, providers from . import http, monitors, dispatcher class ApplicationContainer(containers.DeclarativeContainer): config = providers.Configuration() configure_logging = providers.Callable( logging.basicConfig, stream=sys.stdout, level=config.log.level, format=config.log.format, ) http_client = providers.Factory(http.HttpClient) example_monitor = providers.Factory( monitors.HttpMonitor, http_client=http_client, options=config.monitors.example, ) httpbin_monitor = providers.Factory( monitors.HttpMonitor, http_client=http_client, options=config.monitors.httpbin, ) dispatcher = providers.Factory( dispatcher.Dispatcher, monitors=providers.List( example_monitor, httpbin_monitor, ), ) Example of running of such application: .. code-block:: python from .containers import ApplicationContainer def main() -> None: container = ApplicationContainer() container.config.from_yaml('config.yml') container.configure_logging() dispatcher = container.dispatcher() dispatcher.run() if __name__ == '__main__': main() Tutorials ========= Tutorial is a good point to start. Choose one of the following: - `Flask web application tutorial `_ - `Aiohttp REST API tutorial `_ - `Asyncio monitoring daemon tutorial `_ Installation ============ - The package is available on the `PyPi`_:: pip install dependency-injector Documentation ============= - The documentation is available on the `Read The Docs `_ Frequently asked questions ========================== What is the dependency injection? - dependency injection is a principle that decreases coupling and increases cohesion Why should I do the dependency injection? - your code becomes more flexible, testable and clear - you have no problems when you need to understand how it works or change it 😎 How do I start doing the dependency injection? - you start writing the code following the dependency injection principle - you register all of your application components and their dependencies in the container - when you need a component, you get it from the container Why do I need a framework for this? - you need the framework for this to not create it by your own - this framework gives you the container and the providers - the container is like a dictionary with the batteries 🔋 - the providers manage the lifetime of your components, you will need factories, singletons, smart config object etc What price do I pay and what do I get? - you need to explicitly specify the dependencies in the container - it will be extra work in the beginning - it will payoff when project grows or in two weeks 😊 (when you forget what project was about) What features does the framework have? - building objects graph - smart configuration object - providers: factory, singleton, thread locals registers, etc - positional and keyword context injections - overriding of the objects in any part of the graph What features the framework does NOT have? - autowiring / autoresolving of the dependencies - the annotations and ``@inject``-like decorators Have a question? - Open a `Github Issue `_ Found a bug? - Open a `Github Issue `_ Want to help? - |star| Star the ``Dependency Injector`` on the `Github `_ - |new| Start a new project with the ``Dependency Injector`` - |tell| Tell your friend about the ``Dependency Injector`` Want to contribute? - |fork| Fork the project - |pull| Open a pull request to the ``develop`` branch .. _PyPi: https://pypi.org/project/dependency-injector/ .. |star| unicode:: U+2B50 U+FE0F .. star sign1 .. |new| unicode:: U+1F195 .. new sign .. |tell| unicode:: U+1F4AC .. tell sign .. |fork| unicode:: U+1F500 .. fork sign .. |pull| unicode:: U+2B05 U+FE0F .. pull sign