Book Image

The Go Workshop

By : Delio D'Anna, Andrew Hayes, Sam Hennessy, Jeremy Leasor, Gobin Sougrakpam, Dániel Szabó
Book Image

The Go Workshop

By: Delio D'Anna, Andrew Hayes, Sam Hennessy, Jeremy Leasor, Gobin Sougrakpam, Dániel Szabó

Overview of this book

The Go Workshop will take the pain out of learning the Go programming language (also known as Golang). It is designed to teach you to be productive in building real-world software. Presented in an engaging, hands-on way, this book focuses on the features of Go that are used by professionals in their everyday work. Each concept is broken down, clearly explained, and followed up with activities to test your knowledge and build your practical skills. Your first steps will involve mastering Go syntax, working with variables and operators, and using core and complex types to hold data. Moving ahead, you will build your understanding of programming logic and implement Go algorithms to construct useful functions. As you progress, you'll discover how to handle errors, debug code to troubleshoot your applications, and implement polymorphism using interfaces. The later chapters will then teach you how to manage files, connect to a database, work with HTTP servers and REST APIs, and make use of concurrent programming. Throughout this Workshop, you'll work on a series of mini projects, including a shopping cart, a loan calculator, a working hours tracker, a web page counter, a code checker, and a user authentication system. By the end of this book, you'll have the knowledge and confidence to tackle your own ambitious projects with Go.
Table of Contents (21 chapters)
Free Chapter
1
1. Variables and Operators
2
2. Logic and Loops

Error Interface Type

What is an error in Go? An error in Go is a value. Here is a quote from Rob Pike, one of the pioneers of Go:

"Values can be programmed, and since errors are values, errors can be programmed. Errors are not like exceptions. There's nothing special about them, whereas an unhandled exception can crash your program."

Since errors are values, they can be passed into a function, returned from a function, and evaluated just like any other value in Go.

An error in Go is anything that implements the error interface. We need to look at some fundamental aspects that make up the error type in Go. To be an error type in Go, it must first satisfy the type error interface:

//https://golang.org/pkg/builtin/#error
type error interface {
  Error()string
}

The wonderful thing about Go is the simplistic design of the language features. This can easily be seen with the error interface. Go's standard library uses the error interface. To satisfy...