go Cobra命令列工具入門教學

package main
  
import (
    "flag"
    "fmt"
)
  
func main() {
    flag.Parse()
  
    args := flag.Args()
    if len(args) <= 0 {
        fmt.Println("Usage:  admin-cli [command]")
        return
    }
  
    switch args[0] {
    case "help":
        // ...
    case "export":
        //...
        if len(args) == 3 { // 匯出到檔案
            // todo
        } else if len(args) == 2 { // 匯出...
            // todo
        }
    default:
        //...
    }
}

package main
import (
    "fmt"
    "github.com/spf13/cobra"
    "os"
)
// rootCmd represents the base command when called without any subcommands
var rootCmd = &cobra.Command{
    Use:   "api",
    Short: "A brief description of your application",
    Long:  `A longer description `,
}
// 命令一
var mockMsgCmd = &cobra.Command{
    Use:   "mockMsg",
    Short: "批次傳送測試文字訊息",
    Long:  ``,
    Run: func(cmd *cobra.Command, args []string) {
        fmt.Println("mockMsg called")
    },
}
// 命令二
var exportCmd = &cobra.Command{
    Use:   "export",
    Short: "匯出資料",
    Long:  ``,
    Run: func(cmd *cobra.Command, args []string) {
        fmt.Println("export called")
    },
}
func Execute() {
    err := rootCmd.Execute()
    if err != nil {
        os.Exit(1)
    }
}
func init() {
    rootCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
    rootCmd.AddCommand(mockMsgCmd)
    rootCmd.AddCommand(exportCmd)
    exportCmd.Flags().StringP("out", "k", "./backup", "匯出路徑")
}
func main() {
    Execute()
}

$ go run main.go
A longer description
Usage:
  api [command]
Available Commands:
  completion  Generate the autocompletion script for the specified shell
  export      匯出資料
  help        Help about any command
  mockMsg     批次傳送測試文字訊息
Flags:
  -h, --help     help for api
  -t, --toggle   Help message for toggle
Use "api [command] --help" for more information about a command.

$ ./appName command args --Flag

$ go get -u github.com/spf13/cobra@latest

import "github.com/spf13/cobra"

# 命令列工具
$ go install github.com/spf13/cobra-cli@latest

$ cobra-cli --help
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-cli [command]
  
Available Commands:
  add         Add a command to a Cobra Application
  completion  Generate the autocompletion script for the specified shell
  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-cli
  -l, --license string   name of license for the project
      --viper            use Viper for configuration
  
Use "cobra-cli [command] --help" for more information about a command.

$ cobra-cli init

├── LICENSE
├── cmd
│   └── root.go
└── main.go

package main
  
import "tools/api/cmd"
  
func main() {
   cmd.Execute()
}

root.go（有刪減）：

package cmd
import (
   "fmt"
   "github.com/spf13/cobra"
)
// rootCmd represents the base command when called without any subcommands
var rootCmd = &cobra.Command{
   Use:   "api",
   Short: "A brief description of your application",
   Long:  `A longer description `,
   //Run: func(cmd *cobra.Command, args []string) {
   // fmt.Println("api called")
   //},
}
// 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() {
   err := rootCmd.Execute()
   if err != nil {
      os.Exit(1)
   }
}
func init() {
   // 全域性flag
   // rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.api.yaml)")
   // local flag，暫不知道用處
   rootCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
}

$ go build
$ ./api

$ cobra-cli add [command]

$ cobra-cli add mock-msg
mockMsg created at /Users/xxx/repo/tools/api

package cmd
import (
   "fmt"
   "github.com/spf13/cobra"
)
var mockMsgCmd = &cobra.Command{
   Use:   "mockMsg",
   Short: "A brief description of your command",
   Long: `mock msg command`,
   Run: func(cmd *cobra.Command, args []string) {
      fmt.Println("mockMsg called")
   },
}
func init() {
   rootCmd.AddCommand(mockMsgCmd)
}

$ go build
$ ./api

// ...
Available Commands:
  completion  Generate the autocompletion script for the specified shell
  help        Help about any command
  mockMsg     A brief description of your command
// ...

$ ./api mockMsg
mockMsg called

./api mockMsg help
批次生產mq訊息
  
Usage:
  benchmark mockmsg [flags]
  
Flags:
  -g, --goroutine int32   並行routine數量 (default 1)
  -h, --help              help for mockmsg
  -p, --packet int32      每個routine一秒寫入mq的數量 (default 20)

func init() {
   mockmsgCmd.Flags().Int32P("goroutine", "g", 1, "並行routine數量")
   mockmsgCmd.Flags().Int32P("packet", "p", 20, "每個routine一秒寫入mq的數量")
  
   rootCmd.AddCommand(mockmsgCmd)
}

// mockmsgCmd represents the mockmsg command
var mockmsgCmd = &cobra.Command{
   Use:   "mockmsg",
   Short: "批次生產mq訊息",
   Run: func(cmd *cobra.Command, args []string) {
      // 這裡要寫全名
      g, _ := cmd.Flags().GetInt32("goroutine")
      p, _ := cmd.Flags().GetInt32("packet")
      fmt.Println("mockmsg called,flags:g=", g, ",p=", p, ",args:", args)
   },
}

$ go run main.go mockmsg -p 322 -g 5 args1 args2
mockmsg called,flags:g= 5 ,p= 322 ,args: [args1 args2]