package main

import (

    "fmt"

    "log"

    "os"

    "github.com/urfave/cli"

)

func main() {

    app := cli.NewApp()

    var flags []cli.Flag

    flags = append(flags, cli.StringFlag{

        Name:  "host",

        Value: "0.0.0.0",

        Usage: "bind host",

    }, cli.IntFlag{

        Name:  "port,p",

        Value: ,

        Usage: "bind port",

    }, cli.StringFlag{

        Name:  "env,e",

        Value: "prod",

        Usage: "runtime environment, dev|test|prod",

    })

    app.Flags = flags

    app.Action = func(c *cli.Context) error {

        fmt.Println("host:", c.String("host"))

        fmt.Println("port:", c.String("port"))

        fmt.Println("env:", c.String("env"))

        return nil

    }

    err := app.Run(os.Args)

    if err != nil {

        log.Fatal(err)

    }

}