Book Image

Mastering Go – Third Edition - Third Edition

By : Mihalis Tsoukalos
5 (2)
Book Image

Mastering Go – Third Edition - Third Edition

5 (2)
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)
14
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15
Index

Finding cycles in a UNIX file system

This section implements a practical UNIX command-line utility that can find cycles (loops) in UNIX file systems. The idea behind the utility is that with UNIX symbolic links, there is a possibility to create cycles in our file system. This can perplex backup software such as tar(1) or utilities such as find(1) and can create security-related issues. The presented utility, which is called FScycles.go, tries to inform us about such situations.

The idea behind the solution is that we keep every visited directory path in a map and if a path appears for the second time, then we have a cycle. The map is called visited and is defined as map[string]int.

If you are wondering why we are using a string and not a byte slice or some other kind of slice as the key for the visited map, it is because maps cannot have slices as keys because slices are not comparable.

The output of the utility depends on the root path used for initialing...