version/main.go

package main

import (
	"fmt"
	"io/ioutil"
	"os"
	"os/exec"
)

const warning = "//WARNING! DO NOT EDIT THIS FILE BY HAND. IT IS AUTO GENERATED.\n"

const header = "package main\n"

const code = `
import (
	"fmt"
	"os"
    "strings"
)

func init() {
	flagIsSet := func(arg string, sfortFlag string) bool {
        arg = strings.Split(arg, "=")[0]
        if len(arg)>1 {
            if arg[0] == "-"[0] && arg[1] != "-"[0] {
                return strings.Contains(arg, sfortFlag)
            }
        }
        return false
    }

    for _, arg := range os.Args {
        if flagIsSet(arg, "v") || arg == "--version" {
            fmt.Println(gitVersion)
            os.Exit(0)
        }
    }
}
const gitVersion = "`

func main() {
	cmd := exec.Command("git", "describe", "--tags", "--abbrev=0")
	out, err := cmd.Output()
	if err != nil {
		fmt.Println(err)
		os.Exit(0)
	}
	version := string(out)
	version = version[:len(version)-1]
	content := warning + header + code + version + "\""

	ioutil.WriteFile("version.go", []byte(content), 0644)
}