Powerful Command-Line Applications in Go: Build Fast and Maintainable Tools

Gerardi, Ricardo

  • 出版商: Pragmatic Bookshelf
  • 出版日期: 2022-01-11
  • 定價: $1,520
  • 售價: 9.5$1,444
  • 貴賓價: 9.0$1,368
  • 語言: 英文
  • 頁數: 250
  • 裝訂: Paperback
  • ISBN: 168050696X
  • ISBN-13: 9781680506969
  • 立即出貨 (庫存 < 3)



Whether you want to automate tasks, analyze data, parse logs, talk to network services, or address other systems requirements, writing your own command-line tool may be the fastest - and perhaps the most fun - way to do it. The Go programming language is a great choice for developing tools that are fast, reliable, and cross-platform. Create command-line tools that work with files, connect to services, and even manage external processes, all while using tests and benchmarks to ensure your programs are fast and correct.

When you want to develop cross platform command-line tools that are fast and reliable, use Go, a modern programming language that combines the reliability of compiled languages with the ease of use and flexibility of dynamic typed languages. Work through practical examples to develop elegant and efficient tools by applying Go's rich standard library, its built in support for concurrency, and its expressive syntax. Use Go's integrated testing capabilities to automatically test your tools, ensuring they work reliably even across code refactoring.

Develop CLI tools that interact with your users by using common input/output patterns, including environment variables and flags. Handle files to read or persist data, and manipulate paths consistently in cross-platform scenarios. Control processes and handle signals, and use a benchmark driven approach and Go's concurrency primitives to create tools that perform well. Use powerful external libraries such as Cobra to create modern and flexible tools that handle subcommands, and develop tools that interact with databases, APIs, and network services. Finally, leverage what you learned by tackling additional challenges at the end of each chapter.

What You Need:

Go 1.8 or higher, an internet connection to download the example files and additional libraries, and a text editor to write your programs.


Ricardo Gerardi is an IT professional with over 20 years experience in large and small companies. He's currently working as Automation Consultant at Red Hat. Ricardo has been developing command line tools for a long time, for different purposes including automation, monitoring, and data analysis tools, and he has now adopted Go for all his projects.


What’s in This Book
How to Use This Book
About Example Code
Go Modules
Online Resources
Your First Command Line Program in Go excerpt
Building the Basic Word Counter
Testing the Basic Word Counter
Adding Command Line Flags
Compiling your Tool for Different Platforms

Interacting with Your Users
Organizing your Code
Defining the To-Do API
Creating the Initial To-Do Command Line Tool
Testing the Initial CLI Implementation
Handling Multiple Command Line Options
Display Command Line Tool Usage
Improving the List Output Format
Increasing Flexibility with Environment Variables
Capturing Input from STDIN

Working with Files in Go
Creating a Basic Markdown Preview Tool
Writing Tests for the Markdown Preview Tool
Adding Temporary Files to the Markdown Preview Tool
Using Interfaces to Automate Tests
Adding an Auto-Preview Feature
Cleaning Up Temporary Files
Improving the Markdown Preview Tool with Templates

Navigating the File System
Developing a File System Crawler
Testing with Table Driven Testing
Deleting Matched Files
Testing with the Help of Test Helpers
Logging Deleted Files
Archiving Files

Improving the Performance of your CLI Tools
Developing the Initial Version of colStats
Writing Tests for ColStats
Benchmarking your Tool
Profiling your Tool
Reducing Memory Allocation
Tracing your Tool
Improving the colStats Tool to Process Files Concurrently
Reduce Scheduling Contention

Controlling Processes
Executing External Programs
Writing tests for Goci
Defining a Pipeline
Adding Another Step to the Pipeline
Handling Output from External Programs
Running Commands with Contexts
Integration Tests with a Local Git Server
Testing Commands with Mock Resources
Handling Signals

Talking to REST APIs
Using the Cobra CLI Framework
Developing Interactive Terminal Tools
Working with Regular Expressions in Go
Distributing Your Tool