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)

Advantages of off-the-shelf injection

While we have been talking specifically about Wire so far in this chapter, I would like to take a moment to discuss the advantages of off-the-shelf injection in a more general sense. When evaluating a tool or framework, it's essential to cast a critical eye over the advantages, disadvantages, and effects on your code that it may have.

Some of the possible advantages of off-the-shelf injection include the following.

A reduction in boilerplate code—After applying constructor injection to a program, it's common that the main() function becomes bloated with the instantiation of objects. As the project grows, so does main(). While this does not impact the performance of the program, it does become inconvenient to maintain.

Many dependency injection frameworks aim to either remove this code or move it elsewhere. As we will...