jwtgen/main.go

package main

import (
	"flag"
	"fmt"
	"os"
	"time"

	"github.com/dgrijalva/jwt-go"
)

func main() {

	secret := os.Getenv("JWT_SECRET")

	if secret == "" {
		fmt.Println("No secret in environment")
	}

	hostname, err := os.Hostname()
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Println(hostname)

	usernameFlag := flag.String("username", "demo", "username to use when generating jwt token")
	issuerFlag := flag.String("issuer", "issuer.golang.com", "issuer to use when generating jwt token")
	expireFlag := flag.Int("expire", 0, "expire how many hours when generating jwt token")
	adminFlag := flag.Bool("admin", false, "should the user be admin?")
	writeFlag := flag.Bool("write", false, "should the user be able to write?")
	readFlag := flag.Bool("read", true, "should the user be able to read?")

	flag.Parse()

	var token *jwt.Token
	if *expireFlag == 0 {
		token = jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
			"username": *usernameFlag,
			"admin":    *adminFlag,
			"write":    *writeFlag,
			"read":     *readFlag,
			"iss":      *issuerFlag,
			"iat":      time.Now().Unix(),
		})
	} else {
		token = jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
			"username": *usernameFlag,
			"admin":    *adminFlag,
			"write":    *writeFlag,
			"read":     *readFlag,
			"iss":      *issuerFlag,
			"exp":      time.Now().Add(time.Hour * time.Duration(*expireFlag)).Unix(),
			"iat":      time.Now().Unix(),
		})
	}
	tokenString, err := token.SignedString([]byte(secret))
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Printf("Generated JWT token for\n")
	fmt.Printf("Username: %s\n", *usernameFlag)
	fmt.Printf("Admin: %v\n", *adminFlag)
	fmt.Printf("Write: %v\n", *writeFlag)
	fmt.Printf("Read: %v\n", *readFlag)
	fmt.Printf("Issuer: %s\n", *issuerFlag)
	fmt.Printf("Expire: %d hours\n", *expireFlag)
	fmt.Println("-------- Token --------")
	fmt.Printf("%s\n", tokenString)
	fmt.Println("-----------------------")
}