【Go】Cobra Go最强大的命令行工具【1】

coolliuzw 收录于 go

2020-12-12 约 1100 字预计阅读 3 分钟次阅读

简单的介绍一个Go语言必须的库，强大的命令行工具.

简介

Cobra既是一个用于创建功能强大的现代CLI应用程序的库，也是一个生成应用程序和命令文件的程序。

Cobra被用于许多Go项目中，比如Kubernetes、Hugo和githubcli等等。

github地址: cobra

准备工作

安装

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go get -u github.com/spf13/cobra

然后在你的项目引入Cobra的包:

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import "github.com/spf13/cobra"

go get后，也会给系统安一个cobra的工具，我们可以使用这个工具生成项目的demo。

工具常用命令

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$ cobra -h                                      
Cobra is a CLI library for Go that empowers applications.
This application is a tool to generate the needed files
to quickly create a Cobra application.

Usage:
  cobra [command]

Available Commands:
  add         Add a command to a Cobra Application
  help        Help about any command
  init        Initialize a Cobra Application

Flags:
  -a, --author string    author name for copyright attribution (default "YOUR NAME")
      --config string    config file (default is $HOME/.cobra.yaml)
  -h, --help             help for cobra
  -l, --license string   name of license for the project
      --viper            use Viper for configuration (default true)

Use "cobra [command] --help" for more information about a command.

基础实践

demo工程项目生成

建议cobra空文件夹
使用go mod初始化文件 go mod init cobra

使用cobra工具生成项目文件:

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cobra init --pkg-name cobra --author coolliuzw

运行测试

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$ go run main.go            
A longer description that spans multiple lines and likely contains
examples and usage of using your application. For example:

Cobra is a CLI library for Go that empowers applications.
This application is a tool to generate the needed files
to quickly create a Cobra application.

步骤执行完成后，就有一个基本可运行的命令行demo。

demo程序修改

go run main.go，demo输出的是以上的内容，那么我们应该如何去修改他呢？跟我来：

vim cmd/root.go 就能看到输出的这段代码了。cobra自动生成命令行都放置在cmd这个目录下。

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// rootCmd represents the base command when called without any subcommands
var rootCmd = &cobra.Command{
	Use:   "cobra",
	Short: "A brief description of your application",
	Long: `A longer description that spans multiple lines and likely contains
examples and usage of using your application. For example:

Cobra is a CLI library for Go that empowers applications.
This application is a tool to generate the needed files
to quickly create a Cobra application.`,
	// Uncomment the following line if your bare application
	// has an action associated with it:
	//	Run: func(cmd *cobra.Command, args []string) { },
}

demo也有一些注释说明简单的用法，我们来修改一下demo在测试一下。

修改

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// rootCmd represents the base command when called without any subcommands
var rootCmd = &cobra.Command{
  Use:   "cobra",
  Short: "A brief description of coolliuzw",
  Long: `A longer description of coolliuzw blog`,
  // Uncomment the following line if your bare application
  // has an action associated with it:
  //	Run: func(cmd *cobra.Command, args []string) { },
}

运行

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go run main.go   
A longer description of coolliuzw blog

具体修改了什么看一下代码的注释。

添加自定义Cli命令

添加version命令行工具.
cobra add version --author coolliuzw
cmd目录下多了一个version.go的文件。

尝试修改version测试

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// versionCmd represents the version command
var versionCmd = &cobra.Command{
	Use:   "version",
	Short: "A brief description of version",
	Long: `A longer description of version long`,
	Run: func(cmd *cobra.Command, args []string) {
      fmt.Println("version called")
	},
}

查看是否添加成功

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go run main.go help   
A longer description of coolliuzw blog

Usage:
  cobra [command]

Available Commands:
  help        Help about any command
  version     A brief description of version

Flags:
      --config string   config file (default is $HOME/.cobra.yaml)
  -h, --help            help for cobra
  -t, --toggle          Help message for toggle

Use "cobra [command] --help" for more information about a command.

//go run main.go help可以看程序支持的命令行.
//version     A brief description of version也添加进去了

测试调用.

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$ go run main.go version
version called
// 成功调用

总结

这边只说说demo怎么构建起来，是不是很简单。去创建你的cli工具吧