base32-guid-gen/main.go

package main

import (
	"encoding/base32"
	"flag"
	"fmt"
	"github.com/google/uuid"
)

var flagHelp bool
var flagPrefix string
var flagLowerCase bool

const UpperCaseEncoding = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"
const LowerCaseEncoding = "abcdefghijklmnopqrstuvwxyz234567"

func main() {
	flag.BoolVar(&flagHelp, "h", false, "show help")
	flag.StringVar(&flagPrefix, "p", "", "add prefix for generated uuid")
	flag.BoolVar(&flagLowerCase, "l", false, "lowercase encoding")
	flag.Parse()
	if flagHelp {
		flag.PrintDefaults()
		return
	}
	id := uuid.New()
	b, err := id.MarshalBinary()
	if err != nil {
		fmt.Println("failed marshal uuid to []byte: ", err)
		return
	}
	var encStr string
	if flagLowerCase {
		encStr = LowerCaseEncoding
	} else {
		encStr = UpperCaseEncoding
	}
	b32Encoding := base32.NewEncoding(encStr)
	b32Encoding = b32Encoding.WithPadding('9')
	b32Str := b32Encoding.EncodeToString(b)
	out := fmt.Sprintf("%s%s", flagPrefix, b32Str)
	fmt.Println(out)
}