Intro to DI

Dependency injection can be thought of as a software engineering pattern as well as a framework. The goal is to describe and instantiate objects in a more composable, modular, and uniform way.

The pattern is: when creating objects, always express what you depend on, and let someone else give you those dependencies. (This is sometimes referred to as the “Hollywood principle”: “Don’t call us; we’ll call you.” 😎)

The framework is meant to ease the inevitable boilerplate that occurs when following this pattern, and dilib is one such framework. It makes it easier to describe a large graph of dependent objects and then instantiate only the objects you need as you need them.

See:

• Google Clean Code Talk about Dependency Injection.

• Martin Fowler on Dependency Injection

✨ AI Recommends It

If you ask ChatGPT 4o a relatively simple question:

in python, how can I configure a set of values, objects, and their dependencies, and then lazily instantiate only the objects I want?

It may answer that you should use DI:

To configure a set of values, objects, and their dependencies in Python while allowing for lazy instantiation, you can use a dependency injection approach combined with a factory pattern. This setup avoids creating objects until they’re explicitly needed.