Generic function to load and parse environment variable in Go

generic-env.go

func getEnv[T int | string | bool](str string) T {
	env, ok := os.LookupEnv(str)
	if !ok {
		log.Fatalf("%s environment variable required but not set", str)
	}

	var v T
	switch t := any(&v).(type) {
	case *string:
		*t = env
	case *int:
		i, err := strconv.Atoi(env)
		if err != nil {
			log.Fatal(err)
		}
		*t = int(i)
	case *bool:
		b, err := strconv.ParseBool(env)
		if err != nil {
			log.Fatal(err)
		}
		*t = bool(b)
	}

	return v
}