A simple dependency injection module using python 3 annotations

dependency, injection, annotation, inject, di, injector, management, ioc, inversion, of, control
pip install py3njection==1.4.1



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How to use

from py3njection import inject
from some_package import ClassToInject

class Demo:
    def __init__(self, object_to_use: ClassToInject):
        self.dependency = object_to_use

demo = Demo()

How does it work ?

The decorator @inject looks for any annotated method/function parameters (return annotation excluded).

It creates a new object from the specified class if no object is already provided.

What if I want a singleton ?

class ClassToInject:

That's it ! When @inject sees a class with this decorator, it always uses the same instance.

How to install

It's available on PyPI !

pip install py3injection

Or get it at :

Want to know more ?

A more complete documentation is available here :

Contact and Contribution

Feel free to contribute in any way :

Some Notes

  • Unit tests come easy to set up (unless you have too many dependencies, but that would be a code smell, right ?). Just specify mock instances at your object creation. Examples will come later.
  • This also means the injected object could also have some of its members injected too at their initialization !