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)

Goals for our system

Have you ever tried to grow your own vegetables from seed? It's a long, slow, but gratifying experience. Building great code is no different. In gardening, it's perhaps more common to skip the first step and buy plants as seedlings from the nursery, and programming is much the same. Most of the time, when we join a project, the code already exists; sometimes it's happy and healthy, but often it's sick and dying.

In this situation, we are adopting a system. It works, but has a few thorns—Ok, maybe more than a few. With some tender loving care, we will turn this system into something healthy and thriving.

So, how do we define a healthy system? The system we have works; it does what the business needs it to do. That's enough, right?

Absolutely not! We might explicitly be paid to deliver a certain amount of features...