gistfile1.txt

    cfg.lcurls, err = flags.URLsFromFlags(cfg.FlagSet, "listen-client-urls", "bind-addr", cfg.clientTLSInfo)
    if err != nil {
        return err
    }
    cfg.acurls, err = flags.URLsFromFlags(cfg.FlagSet, "advertise-client-urls", "addr", cfg.clientTLSInfo)
    if err != nil {
        return err
    }
    cfg.resolveUrls()

    return nil
}

func (cfg *config) resolveUrls() {
    for _, urls := range [][]url.URL{cfg.lpurls, cfg.apurls, cfg.lcurls, cfg.acurls} {
        rUrls := make([]url.URL, 0)
        for _, u := range urls {
            ip := net.ParseIP(u.Host)
            if ip != nil {
                rUrls = append(rUrls, u)
                continue
            }
            tcpAddr, err := net.ResolveTCPAddr("tcp", u.Host)
            if err != nil {
                log.Println("Couldn't resolve host" + u.Host)
            }
            log.Printf("etcd: Resolving DNS hostname %s to %s", u.Host, tcpAddr.String())
            u.Host = tcpAddr.String()
            rUrls = append(rUrls, u)
        }
        urls = rUrls
    }
}