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)

Off-the-shelf injection with Wire

The Go Cloud project is an initiative that intends to make it easier for application developers to deploy cloud applications on any combination of cloud providers seamlessly. The integral part of this project is a code generation-based dependency injection tool called Wire.

Wire is a good fit for our example service as it promotes the use of explicit instantiation and discourages the use of global variables; just as we attempted to achieve in our refactoring in previous chapters. Additionally, Wire uses code generation to avoid any performance penalties or code complexity that can result from the use of runtime reflection.

Perhaps the most useful aspect of Wire for us is its simplicity. After we understand a few simple concepts, the code we have to write and the code that is generated is reasonably straightforward.

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