github.com/packtpublishing/hands-on-dependency-injection-in-go

Hands-On Dependency Injection in Go

This is the code repository for Hands-On Dependency Injection in Go, published by Packt.

Develop clean Go code that is easier to read, maintain, and test

What is this book about?

Hands-On Dependency Injection in Go takes you on a journey, refactoring existing code to adopt dependency injection (DI) using various methods available in Go.

This book covers the following exciting features:

• Understand the benefits of dependency injection
• Explore SOLID design principles and how they relate to Go
• Analyze various dependency injection patterns available in Go
• Leverage DI to produce high quality, loosely coupled Go code
• Refactor existing Go code to adopt dependency injection
• Discover tools to improve your code's testability and test coverage
• Generate and interpret Go dependency graphs

If you feel this book is for you, get your copy today!

Instructions and Navigations

All of the code is organized into folders. For example, ch02.

The code will look like the following:

html, body, #map {
 height: 100%; 
 margin: 0;
 padding: 0
}

Following is what you need for this book: Hands-On Dependency Injection in Go is for programmers with a few year s experience in any language and a basic understanding of Go. If you wish to produce clean, loosely coupled code that is inherently easier to test, this book is for you.

Getting the source

The easiest way to obtain the source code is to use go get.
This will ensure that the code is placed in the correct directory and should be then runnable and testable.

To download this repo use go get github.com/PacktPublishing/Hands-On-Dependency-Injection-in-Go/...

Code Organization

In this repository, there is 1 folder for every chapter of the book, named chXX where XX is the chapter number.

The code provided are expanded versions of the code presented in the book. While it will compile and typically will not throw an error when passed into go test it is not designed to be executed.

From chapter 4 onwards, there is an acme directory included with the code that chapter. The acme directory is the code for the sample service presented in the book with the changes discussed in that chapter already applied.

You will also find 2 additional directories in the root of the repository:

• resources - this directory contains an SQL file that should be used to populate a MySQL database. This database is used by the sample service
• vendor - this is standard go vendor directory which contains the external packages required by the sample service

Setting up the MySQL database

The easiest way to create and populate the database required by the sample service is by running the following:

mysql < ./resources/create.sql

Depending on your settings you may want to provide a username and password like this:

mysql -u [your username] -p < ./resources/create.sql

This will create a database called acme with 1 table and 4 records.

Creating a free account on CurrencyLayer

The sample service uses a free currency conversion service. In order to successfully run all the examples, you will need to sign up here and obtain an API Key.

Configuring the sample service

Now that you have your MySQL and CurrencyLayer credentials you can create a config for the sample service.

1. Copy default-config.json (found next to this file) to config.json
2. Open config.json in your favorite editor
3. Add your database credentials to the "dsn" setting. Should be in the form: "[username]:[password]@tcp(localhost:3306)/[database name]?autocommit=true"
4. Add your API Key to the "exchangeRateAPIKey" setting. Should be in the form: "1234567890abcdef1234567890abcdef"

Running the sample service for a particular chapter

To run sample service for a particular chapter:

1. First make sure you are in the base of this repository: cd $GOPATH/src/github.com/PacktPublishing/Hands-On-Dependency-Injection-in-Go/
2. Use a command similar to the following (which is for ch04): ACME_CONFIG=$GOPATH/src/github.com/PacktPublishing/Hands-On-Dependency-Injection-in-Go/config.json go run ./ch04/acme/main.go

Special instructions for chapters 10-12

As we have multiple files and tests in the main package, we cannot use the standard go run ./ch10/acme/main.go to run the service.

Instead we need to modify the command to go run ./ch10/acme/main.go ./ch10/acme/wire_gen.go

Running tests for a chapter

To run sample service for a particular chapter you can use a command similar to the follow (which is for ch04):

1. First make sure you are in the base of this repository: cd $GOPATH/src/github.com/PacktPublishing/Hands-On-Dependency-Injection-in-Go/
2. Use a command similar to the following (which is for ch04): ACME_CONFIG=$GOPATH/src/github.com/PacktPublishing/Hands-On-Dependency-Injection-in-Go/config.json go test ./ch04/...

With the following software and hardware list you can run all code files present in the book (Chapter 1-12).

Software and Hardware List

Chapter	Software required	OS required
1-12	Go 1.10.x+	Windows, Mac OS X, and Linux (Any)
4-12	MySQL 5.7.x+	Windows, Mac OS X, and Linux (Any)
4-12	CurrencyLayer	Windows, Mac OS X, and Linux (Any)

Related products

• Mastering Go [Packt] [Amazon]

• Go Standard Library Cookbook [Packt] [Amazon]

Get to Know the Author

Corey Scott is a senior software engineer currently living in Melbourne, Australia. He’s been programming professionally since 2000, with the last 5 years spent building large-scale distributed services in Go. An occasional technical speaker and blogger on a variety of software-related topics, he is passionate about designing and building quality software. He believes that software engineering is a craft that should be honed, debated, and continuously improved. He takes a pragmatic, non-zealot approach to coding and is always up for a good debate about software engineering, continuous delivery, testing, or clean coding.

Other books by the authors

Suggestions and Feedback

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Download a free PDF

If you have already purchased a print or Kindle version of this book, you can get a DRM-free PDF version at no cost.
Simply click on the link to claim your free PDF.

https://packt.link/free-ebook/9781789132762