Book Image

Hands-On Dependency Injection in Go

By : Corey Scott
Book Image

Hands-On Dependency Injection in Go

By: Corey Scott

Overview of this book

Hands-On Dependency Injection in Go takes you on a journey, teaching you about refactoring existing code to adopt dependency injection (DI) using various methods available in Go. Of the six methods introduced in this book, some are conventional, such as constructor or method injection, and some unconventional, such as just-in-time or config injection. Each method is explained in detail, focusing on their strengths and weaknesses, and is followed with a step-by-step example of how to apply it. With plenty of examples, you will learn how to leverage DI to transform code into something simple and flexible. You will also discover how to generate and leverage the dependency graph to spot and eliminate issues. Throughout the book, you will learn to leverage DI in combination with test stubs and mocks to test otherwise tricky or impossible scenarios. Hands-On Dependency Injection in Go takes a pragmatic approach and focuses heavily on the code, user experience, and how to achieve long-term benefits through incremental changes. By the end of this book, you will have produced clean code that’s easy to test.
Table of Contents (15 chapters)

Applying JIT injection

In previous sections, I alluded to the fact that JIT injection can be used with private and public dependencies, two very different use cases. In this section, we will apply both options to achieve very different results.

Private dependencies

There are many places we could improve our service by applying JIT injection. So, how do we decide? Let's see what our dependency graph has to say:

There are lots of connections going into the logging package. But we have already decoupled that a reasonable amount in Chapter 8, Dependency Injection by Config.

The next package with the most users is the data package. We worked on that back in Chapter 5, Dependency Injection with Monkey Patching, but maybe...