Dependency Injector
?Dependency Injector
is a dependency injection framework for Python.
It helps implement the dependency injection principle.
Key features of the Dependency Injector
:
Factory
, Singleton
, Callable
, Coroutine
, Object
,
List
, Dict
, Configuration
, Resource
, Dependency
, and Selector
providers
that help assemble your objects.
See Providers.yaml
, ini
, and json
files, pydantic
settings,
environment variables, and dictionaries.
See Configuration provider.mypy
-friendly.
See Typing and mypy.Cython
.from dependency_injector import containers, providers
from dependency_injector.wiring import Provide, inject
class Container(containers.DeclarativeContainer):
config = providers.Configuration()
api_client = providers.Singleton(
ApiClient,
api_key=config.api_key,
timeout=config.timeout,
)
service = providers.Factory(
Service,
api_client=api_client,
)
@inject
def main(service: Service = Provide[Container.service]) -> None:
...
if __name__ == "__main__":
container = Container()
container.config.api_key.from_env("API_KEY", required=True)
container.config.timeout.from_env("TIMEOUT", as_=int, default=5)
container.wire(modules=[__name__])
main() # <-- dependency is injected automatically
with container.api_client.override(mock.Mock()):
main() # <-- overridden dependency is injected automatically
When you call the main()
function the Service
dependency is assembled and injected automatically.
When you do testing, you call the container.api_client.override()
method to replace the real API
client with a mock. When you call main()
, the mock is injected.
You can override any provider with another provider.
It also helps you in a re-configuring project for different environments: replace an API client with a stub on the dev or stage.
With the Dependency Injector
, object assembling is consolidated in a container. Dependency injections are defined explicitly.
This makes it easier to understand and change how an application works.
Visit the docs to know more about the Dependency injection and inversion of control in Python.
The package is available on the PyPi:
pip install dependency-injector
The documentation is available here.
Choose one of the following:
Choose one of the following:
The framework stands on the PEP20 (The Zen of Python) principle:
Explicit is better than implicit
You need to specify how to assemble and where to inject the dependencies explicitly.
The power of the framework is in its simplicity.
Dependency Injector
is a simple tool for the powerful concept.
Dependency Injector
on the GithubDependency Injector
Dependency Injector
develop
branch