Book Image

Mastering Go - Third Edition

By : Mihalis Tsoukalos
5 (1)
Book Image

Mastering Go - Third Edition

5 (1)
By: Mihalis Tsoukalos

Overview of this book

Mastering Go is the essential guide to putting Go to work on real production systems. This freshly updated third edition includes topics like creating RESTful servers and clients, understanding Go generics, and developing gRPC servers and clients. Mastering Go was written for programmers who want to explore the capabilities of Go in practice. As you work your way through the chapters, you’ll gain confidence and a deep understanding of advanced Go concepts, including concurrency and the operation of the Go Garbage Collector, using Go with Docker, writing powerful command-line utilities, working with JavaScript Object Notation (JSON) data, and interacting with databases. You’ll also improve your understanding of Go internals to optimize Go code and use data types and data structures in new and unexpected ways. This essential Go programming book will also take you through the nuances and idioms of Go with exercises and resources to fully embed your newly acquired knowledge. With the help of Mastering Go, you’ll become an expert Go programmer by building Go systems and implementing advanced Go techniques in your projects.
Table of Contents (17 chapters)
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Go channels revisited

So far, we have seen basic usages of channels—this section presents the definition and the usage of nil channels, signal channels, and buffered channels.

It helps to remember that the zero value of the channel type is nil, and that if you send a message to a closed channel, the program panics. However, if you try to read from a closed channel, you get the zero value of the type of that channel. So, after closing a channel, you can no longer write to it, but you can still read from it. To be able to close a channel, the channel must not be receive-only.

Additionally, a nil channel always blocks, which means that both reading and writing from nil channels blocks. This property of channels can be very useful when you want to disable a branch of a select statement by assigning the nil value to a channel variable. Finally, if you try to close a nil channel, your program is going to panic. This is best illustrated in the closeNil.go program: