装置cobra
go get -v github.com/spf13/cobra/cobra切换到GOPATH的src目录下并创立一个新文件夹：demo
cd $GOPATH/srcmkdir democd demo初始cobra
$ ../../bin/cobra Cobra is a CLI library for Go that empowers applications.This application is a tool to generate the needed filesto 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 ApplicationFlags: -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.能够看到cobra反对两个命令，一个是init, 一个是add，其中init是初始化一个cobra工程，add是给工程中增加一个子命令
初始化该我的项目：
$ ../../bin/cobra init --pkg-name demo执行完上述命令后会生成如下几个文件及文件夹
$ tree .├── cmd│ └── root.go├── LICENSE└── main.go1 directory, 3 filesmain.go
package mainimport "imgctl/cmd"func main() { cmd.Execute()}cmd/root.go
package cmdimport ( "fmt" "os" "github.com/spf13/cobra" homedir "github.com/mitchellh/go-homedir" "github.com/spf13/viper")var cfgFile string// rootCmd represents the base command when called without any subcommandsvar rootCmd = &cobra.Command{ Use: "cobra-demo", Short: "A brief description of your application", Long: `A longer description that spans multiple lines and likely containsexamples 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 filesto 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) { },}// Execute adds all child commands to the root command and sets flags appropriately.// This is called by main.main(). It only needs to happen once to the rootCmd.func Execute() { if err := rootCmd.Execute(); err != nil { fmt.Println(err) os.Exit(1) }}func init() { cobra.OnInitialize(initConfig) // Here you will define your flags and configuration settings. // Cobra supports persistent flags, which, if defined here, // will be global for your application. rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.cobra-demo.yaml)") // Cobra also supports local flags, which will only run // when this action is called directly. rootCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")}// initConfig reads in config file and ENV variables if set.func initConfig() { if cfgFile != "" { // Use config file from the flag. viper.SetConfigFile(cfgFile) } else { // Find home directory. home, err := homedir.Dir() if err != nil { fmt.Println(err) os.Exit(1) } // Search config in home directory with name ".cobra-demo" (without extension). viper.AddConfigPath(home) viper.SetConfigName(".cobra-demo") } viper.AutomaticEnv() // read in environment variables that match // If a config file is found, read it in. if err := viper.ReadInConfig(); err == nil { fmt.Println("Using config file:", viper.ConfigFileUsed()) }}如果要实现一个没有子命令的CLI工具，那么由cobra生成程序的操作就完结了，因为cobra的所有命令都是通过cobra.Command这个构造体实现的，因而这里就须要对root.go文件中的RootCmd进行批改：
cmd/root.go
package cmdimport ( "fmt" "os" "github.com/spf13/cobra" homedir "github.com/mitchellh/go-homedir" "github.com/spf13/viper")var cfgFile stringvar name stringvar age int// rootCmd represents the base command when called without any subcommandsvar rootCmd = &cobra.Command{ Use: "cobra-demo", Short: "A brief description of your application", Long: `A longer description that spans multiple lines and likely containsexamples 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 filesto 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) { },}// RootCmd represents the base command when called without any subcommandsvar RootCmd = &cobra.Command{ Use: "demo", Short: "A test demo", Long: `Demo is a test appcation for print things`, // Uncomment the following line if your bare application // has an action associated with it: Run: func(cmd *cobra.Command, args []string) { if len(name) == 0 { cmd.Help() return } fmt.Println(name, age) },}// Execute adds all child commands to the root command and sets flags appropriately.// This is called by main.main(). It only needs to happen once to the rootCmd.func Execute() { if err := rootCmd.Execute(); err != nil { fmt.Println(err) os.Exit(1) }}func init() { cobra.OnInitialize(initConfig) // Here you will define your flags and configuration settings. // Cobra supports persistent flags, which, if defined here, // will be global for your application. rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.cobra-demo.yaml)") rootCmd.Flags().StringVarP(&name, "name", "n", "", "person's name") rootCmd.Flags().IntVarP(&age, "age", "a", 0, "person's age") // Cobra also supports local flags, which will only run // when this action is called directly. rootCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")}// initConfig reads in config file and ENV variables if set.func initConfig() { if cfgFile != "" { // Use config file from the flag. viper.SetConfigFile(cfgFile) } else { // Find home directory. home, err := homedir.Dir() if err != nil { fmt.Println(err) os.Exit(1) } // Search config in home directory with name ".cobra-demo" (without extension). viper.AddConfigPath(home) viper.SetConfigName(".cobra-demo") } viper.AutomaticEnv() // read in environment variables that match // If a config file is found, read it in. if err := viper.ReadInConfig(); err == nil { fmt.Println("Using config file:", viper.ConfigFileUsed()) }}到此咱们的demo性能就编码实现了，上面编译运行
解决依赖
go mod initgo mod vendor运行demo
$ go run main.goDemo is a test appcation for print thingsUsage: demo [flags]Flags: -a, --age int person's age -h, --help help for demo -n, --name string person's name增加命令
$ ../../bin/cobra add [cmdname] # 执行后会在cmd目录下生成一个cmdname.go的文件，具体处理函数在该文件中编辑$ ../../bin/cobra add server$ tree.├── cmd│ ├── root.go│ └── server.go # rootCmd的子命令├── LICENSE└── main.go1 directory, 4 filescmd/server.go
package cmdimport ( "fmt" "github.com/spf13/cobra")// serverCmd represents the server commandvar serverCmd = &cobra.Command{ Use: "server", Short: "A brief description of your command", Long: `A longer description that spans multiple lines and likely contains examplesand usage of using your command. For example:Cobra is a CLI library for Go that empowers applications.This application is a tool to generate the needed filesto quickly create a Cobra application.`, Run: func(cmd *cobra.Command, args []string) { fmt.Println("server called") },}func init() { rootCmd.AddCommand(serverCmd) // Here you will define your flags and configuration settings. // Cobra supports Persistent Flags which will work for this command // and all subcommands, e.g.: // serverCmd.PersistentFlags().String("foo", "", "A help for foo") // Cobra supports local flags which will only run when this command // is called directly, e.g.: // serverCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")}$ ../../bin/cobra add create -p "serverCmd" #执行该命令是为server子命令再创立一级子命令，-p --parent$ tree.├── cmd│ ├── create.go # serverCmd的子命令│ ├── root.go│ └── server.go├── LICENSE└── main.go1 directory, 5 filescmd/create.go
package cmdimport ( "fmt" "github.com/spf13/cobra")// creatCmd represents the creat commandvar creatCmd = &cobra.Command{ Use: "creat", Short: "A brief description of your command", Long: `A longer description that spans multiple lines and likely contains examplesand usage of using your command. For example:Cobra is a CLI library for Go that empowers applications.This application is a tool to generate the needed filesto quickly create a Cobra application.`, Run: func(cmd *cobra.Command, args []string) { fmt.Println("creat called") },}func init() { serverCmd.AddCommand(creatCmd) // Here you will define your flags and configuration settings. // Cobra supports Persistent Flags which will work for this command // and all subcommands, e.g.: // creatCmd.PersistentFlags().String("foo", "", "A help for foo") // Cobra supports local flags which will only run when this command // is called directly, e.g.: // creatCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")}