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Python dependency injection framework

Project description

Dependency Injector is a Python dependency injection framework. It was designed to be unified, developer-friendly tool for managing any kind of Python objects and their dependencies in formal, pretty way.

Dependency Injector framework key features are:

  • Easy, smart, pythonic style.
  • Obvious, clear structure.
  • Extensibility and flexibility.
  • Memory efficiency.
  • Thread safety.
  • Documentation.
  • Semantic versioning.


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Dependency Injector library is available on PyPi:

pip install dependency_injector


Brief example below demonstrates usage of Dependency Injector containers and providers for definition of several IoC containers for some microservice system that consists from several business and platform services:

"""Example of several Dependency Injector IoC containers."""

import sqlite3
import boto.s3.connection

import example.main

import dependency_injector.containers as containers
import dependency_injector.providers as providers

class Platform(containers.DeclarativeContainer):
    """IoC container of platform service providers."""

    database = providers.Singleton(sqlite3.connect, ':memory:')

    s3 = providers.Singleton(boto.s3.connection.S3Connection,

class Services(containers.DeclarativeContainer):
    """IoC container of business service providers."""

    users = providers.Factory(,

    auth = providers.Factory(,

    photos = providers.Factory(,

class Application(containers.DeclarativeContainer):
    """IoC container of application component providers."""

    main = providers.Callable(example.main.main,

Next example demonstrates usage of IoC containers & providers defined above:

"""Run example application."""

import containers

if __name__ == '__main__':

    # Previous call is an equivalent of next operations:
    # database = sqlite3.connect(':memory:')
    # s3 = boto.s3.connection.S3Connection(aws_access_key_id='KEY',
    #                                      aws_secret_access_key='SECRET')
    # example.main.main(,
    #         ,
    #                                                      token_ttl=3600),
    #         ,
    #                                                          s3=s3))

Alternative definition styles

Dependecy Injector supports few other styles of dependency injections definition.

IoC containers from previous example could look like these:

class Platform(containers.DeclarativeContainer):
    """IoC container of platform service providers."""

    database = providers.Singleton(sqlite3.connect) \

    s3 = providers.Singleton(boto.s3.connection.S3Connection) \

or like this these:

class Platform(containers.DeclarativeContainer):
    """IoC container of platform service providers."""

    database = providers.Singleton(sqlite3.connect)

    s3 = providers.Singleton(boto.s3.connection.S3Connection)

You can get more Dependency Injector examples in /examples directory on GitHub:


Dependency Injector documentation is hosted on ReadTheDocs:


Feel free to post questions, bugs, feature requests, proposals etc. on Dependency Injector GitHub Issues:

Your feedback is quite important!

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