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

Random Generators

The Go standard library provides utility libraries to create random number generators. The implementations are provided in the crypto/rand and math/rand packages. The math/rand library can be used to generate random integers; however, randomness cannot be guaranteed. Therefore, this library should only be used in cases where the number can be generally random and is not security-sensitive.

Otherwise, you should always use crypto/rand. As a side note, the crypto/rand package relies on OS randomness – for example, on Linux it uses /dev/urandom. Therefore, it is generally slower than the math library implementation.

To produce a random integer between 0 and a user-defined number using the crypto/rand library, we can use the following function:

funcInt(rand io.Reader, max *big.Int) (n *big.Int, err error)

There are many scenarios where we might want to generate a secure random number, for example, when generating unique session IDs. It is important...