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 example.services 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, aws_access_key_id='KEY', aws_secret_access_key='SECRET') class Services(containers.DeclarativeContainer): """IoC container of business service providers.""" users = providers.Factory(example.services.Users, db=Platform.database) auth = providers.Factory(example.services.Auth, db=Platform.database, token_ttl=3600) photos = providers.Factory(example.services.Photos, db=Platform.database, s3=Platform.s3) class Application(containers.DeclarativeContainer): """IoC container of application component providers.""" main = providers.Callable(example.main.main, users_service=Services.users, auth_service=Services.auth, photos_service=Services.photos)Next example demonstrates usage of IoC containers & providers defined above:
"""Run example application.""" import containers if __name__ == '__main__': containers.Application.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(users_service=example.services.Users(db=database), # auth_service=example.services.Auth(db=database, # token_ttl=3600), # photos_service=example.services.Photos(db=database, # s3=s3))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) \ .add_args(':memory:') s3 = providers.Singleton(boto.s3.connection.S3Connection) \ .add_kwargs(aws_access_key_id='KEY', aws_secret_access_key='SECRET')or like this these:
class Platform(containers.DeclarativeContainer): """IoC container of platform service providers.""" database = providers.Singleton(sqlite3.connect) database.add_args(':memory:') s3 = providers.Singleton(boto.s3.connection.S3Connection) s3.add_kwargs(aws_access_key_id='KEY', aws_secret_access_key='SECRET')You can get more Dependency Injector examples in /examples directory on GitHub:
https://github.com/ets-labs/python-dependency-injector
Dependency Injector documentation is hosted on ReadTheDocs:
Feel free to post questions, bugs, feature requests, proposals etc. on Dependency Injector GitHub Issues:
https://github.com/ets-labs/python-dependency-injector/issues
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