neetjn/python-inject-practice

Practice with python dependency injection using python-inject @ https://github.com/ivankorobkov/python-inject

python-inject-practice

Practice with python dependency injection using python-inject @ https://github.com/ivankorobkov/python-inject

This project was created to learn how to perform dependency injection, the pythonic way using python-inject. I'll be recording my thoughts and experiments in this repository.

Experiments

• "instance" injection using python-inject. This injection strategy allows me to pull a binded dependency by object type from my injector given my configuration. See: instance_injection.py

• "attribute" injection using python-inject. This injection strategy allows me to bind a dependency from my injector into class instances. See: attribute_injection.py

• "param" injection using python-inject. This injection strategy allows me to inject dependencies into methods by param position or key. See: param_injection.py

What I've Learned

Preface: Until recently (3/1/2019) I've never knowingly used dependency injection. The design pattern was not something I was consciously aware of, however I leverage it almost daily in both personal projects and in production.

• Dependency injection is more of a development pattern than anything else.
• Contrary to my original confusion, there are multiple ways of tackling dependency injection.
• Angular.js, which I've been actively using for the past couple of years, revolves around dependency injection:

  angular.module('myModule', [])
    .factory('serviceId', ['depService', depService => {
      // ...
    }])*
  

• DI with python-inject can be very powerful with proper context control. IoC can also be incredibly helpful when using asynchronous code.

Resources

• Wikipedia (Dependency injection) - https://en.wikipedia.org/wiki/Dependency_injection
• baeldung (IoC and Dependency Injection in Spring) - https://www.baeldung.com/inversion-control-and-dependency-injection-in-spring
• angularjs/docs - https://docs.angularjs.org/guide/di
• pinject - https://github.com/google/pinject
• preslav (Dependency Injection In Python - The Java Guy's Perspective) - https://preslav.me/2018/12/20/dependency-injection-in-python/

---

Copyright (c) 2019 John Nolette Licensed under the MIT License.