Book Image

Mastering Go - Second Edition

By : Mihalis Tsoukalos
Book Image

Mastering Go - Second Edition

By: Mihalis Tsoukalos

Overview of this book

Often referred to (incorrectly) as Golang, Go is the high-performance systems language of the future. Mastering Go, Second Edition helps you become a productive expert Go programmer, building and improving on the groundbreaking first edition. Mastering Go, Second Edition shows how to put Go to work on real production systems. For programmers who already know the Go language basics, this book provides examples, patterns, and clear explanations to help you deeply understand Go’s capabilities and apply them in your programming work. The book covers the nuances of Go, with in-depth guides on types and structures, packages, concurrency, network programming, compiler design, optimization, and more. Each chapter ends with exercises and resources to fully embed your new knowledge. This second edition includes a completely new chapter on machine learning in Go, guiding you from the foundation statistics techniques through simple regression and clustering to classification, neural networks, and anomaly detection. Other chapters are expanded to cover using Go with Docker and Kubernetes, Git, WebAssembly, JSON, and more. If you take the Go programming language seriously, the second edition of this book is an essential guide on expert techniques.
Table of Contents (20 chapters)
Title Page

Performing DNS lookups

DNS stands for Domain Name System, which relates to the way an IP address is translated into a name, such as, and vice versa. The logic behind the DNS.go utility, which will be developed in this section, is pretty simple: if the given command-line argument is a valid IP address, the program will process it as an IP address; otherwise, it will assume that it is dealing with a hostname that needs to be translated into one or more IP addresses.

The code for the DNS.go utility will be presented in three parts. The first part of the program contains the following Go code:

package main 
import ( 
func lookIP(address string) ([]string, error) { 
    hosts, err := net.LookupAddr(address) 
    if err != nil { 
        return nil, err 
    return hosts, nil 
func lookHostname...