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)

Overview of the improvements

Phew, we made it. How do you think we did? Do you think the improvements were worth the effort? Let's see.

To see how far we have come, we should first recap where we started.

In Chapter 4, Introduction to the ACME Registration Service, we had a small, simple, working service. It got the job done for our users, but it created many inconveniences for those of us that had to maintain and extend it.

Global singletons

One of the biggest pains was undoubtedly the use of global public singletons. At first glance, they seemed to make the code more concise, but they were actually making it much harder for us to test.

The use of init() functions to create variables meant that we either ...