searcherside/handlers/cli/token.go

package cli

import (
	"errors"
	"fmt"
	"log/slog"
	"time"

	"github.com/lestrrat-go/jwx/v2/jwa"
	"github.com/lestrrat-go/jwx/v2/jwt"

	"code.icb4dc0.de/prskr/searcherside/core/ports"
	"code.icb4dc0.de/prskr/searcherside/internal/cli"
)

var ErrJwtSecretRequired = errors.New("JWT secret is required")

type TokenHandler struct {
	Token struct {
		Secret   cli.HexString    `name:"secret" help:"JWT secret"`
		Lifetime time.Duration    `name:"lifetime" help:"JWT lifetime" default:"24h"`
		Subject  string           `name:"subject" help:"JWT subject" default:"${WHOAMI=nobody}"`
		Claims   []cli.TokenClaim `name:"claims" help:"JWT claims"`
	} `embed:"" prefix:"token."`
}

func (h *TokenHandler) Run(stdout ports.STDOUT, logger *slog.Logger) error {
	now := time.Now().UTC()
	if len(h.Token.Secret) == 0 {
		return ErrJwtSecretRequired
	}

	if tokenLength := len(h.Token.Secret); tokenLength < jwtSecretLength {
		logger.Warn(
			"The secret does not have the recommended length",
			slog.Int("actual_length", tokenLength),
			slog.Int("recommended_length", jwtSecretLength),
		)
	}

	token := jwt.New()

	for _, claim := range h.Token.Claims {
		if err := token.Set(claim.Key, claim.Value); err != nil {
			return err
		}
	}

	if err := token.Set(jwt.SubjectKey, h.Token.Subject); err != nil {
		return err
	}

	if err := token.Set(jwt.NotBeforeKey, now); err != nil {
		return err
	}

	if err := token.Set(jwt.ExpirationKey, now.Add(h.Token.Lifetime)); err != nil {
		return err
	}

	tokenString, err := jwt.Sign(token, jwt.WithKey(jwa.HS256, h.Token.Secret.Raw()))
	if err != nil {
		return err
	}

	_, err = fmt.Fprintln(stdout, string(tokenString))

	return err
}