dnscheck.go

package main

import (
	"fmt"
	"log"
	"github.com/miekg/dns"
)

const (
	service         = "servers"
	dockerDNSServer = "127.0.0.11:53"
)

func main() {
	m := &dns.Msg{}
	m.SetQuestion("tasks."+service+".", dns.TypeA)
	c := &dns.Client{}
	in, _, err := c.Exchange(m, dockerDNSServer)
	if err != nil {
		log.Panic(err)
	}

	for _, answer := range in.Answer {
		if a, ok := answer.(*dns.A); ok {
			fmt.Println(a.A)
		}
	}
}