package main

import (
	"net"
	"time"

	"github.com/patrickmn/go-cache"
)

var (
	cnameCache = cache.New(1 * time.Hour, 1 * time.Hour)
)

func lookupCNAME(domain string) (string, error) {
	cname, found := cnameCache.Get(domain)
	if found {
		return cname.(string), nil
	}

	cname, err := net.LookupCNAME(domain)
	if err == nil {
		return cname.(string), nil
	}
	return "", err
}