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 method injection

In this section, we are going to improve our ACME registration service by applying method injection with perhaps my favorite package in the entire Go standard library, the context package. Central to this package is the Context interface, which describes itself as follows:

A context carries a deadline, cancellation signal, and request-scoped values across API boundaries. Its methods are safe for simultaneous use by multiple goroutines

So, why do I love it so much? By applying method injection, with context as the dependency, I am able to build my processing logic in such a way that it can all be automatically canceled and cleaned up.

A quick recap

Before we dive into the changes, let's take...