安装cobra
go get -v github.com/spf13/cobra/cobra
切换到GOPATH的src目录下并创建一个新文件夹：demo
cd $GOPATH/src
mkdir demo
cd 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 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.
可以看到cobra支持两个命令，一个是init, 一个是add，其中init是初始化一个cobra工程，add是给工程中添加一个子命令
初始化该项目：
$ ../../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.go
1 directory, 3 files
main.go
package main
import "imgctl/cmd"
func main() {
cmd.Execute()
}
cmd/root.go
package cmd
import (
"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 subcommands
var rootCmd = &cobra.Command{
Use: "cobra-demo",
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) { },
}
// 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生成程序的操作就结束了，由于cobra的所有命令都是通过cobra.Command这个结构体实现的，因此这里就需要对root.go文件中的RootCmd进行修改：
cmd/root.go
package cmd
import (
"fmt"
"os"
"github.com/spf13/cobra"
homedir "github.com/mitchellh/go-homedir"
"github.com/spf13/viper"
)
var cfgFile string
var name string
var age int
// rootCmd represents the base command when called without any subcommands
var 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())
}
}
到此我们的demo功能就编码完成了，下面编译运行
解决依赖
go mod init
go mod vendor
运行demo
$ go run main.go
Demo is a test appcation for print things
Usage:
demo [flags]
Flags:
-a, --age int person's age
-h, --help help for demo
-n, --name string person's name
添加命令
$ ../../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.go
1 directory, 4 files
cmd/server.go
package cmd
import (
"fmt"
"github.com/spf13/cobra"
)
// serverCmd represents the server command
var serverCmd = &cobra.Command{
Use: "server",
Short: "A brief description of your command",
Long: `A longer description that spans multiple lines and likely contains examples
and 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 files
to 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子命令再创建一级子命令，-p --parent
$ tree
.
├── cmd
│ ├── create.go # serverCmd的子命令
│ ├── root.go
│ └── server.go
├── LICENSE
└── main.go
1 directory, 5 files
cmd/create.go
package cmd
import (
"fmt"
"github.com/spf13/cobra"
)
// creatCmd represents the creat command
var creatCmd = &cobra.Command{
Use: "creat",
Short: "A brief description of your command",
Long: `A longer description that spans multiple lines and likely contains examples
and 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 files
to 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")
}