worker/checks/cdns/a_records.go

// Package cdns provides functionality.
package cdns

import (
	"errors"
	"strconv"

	"github.com/miekg/dns"

	"rocketgit.ru/rsmon/worker/internal/netaddr"
)

// FetchARecords provides functionality.
func FetchARecords(zone, ns string) ([]NSRecord, error) {
	config := dns.ClientConfig{Servers: []string{ns}}
	c := new(dns.Client)
	m := new(dns.Msg)
	m.SetQuestion(zone, dns.TypeA)
	m.RecursionDesired = true
	r, _, err := c.Exchange(m, config.Servers[0]+":53")
	if err != nil {
		return nil, err
	}
	if r.Rcode != dns.RcodeSuccess {
		return nil, errors.New("bad rcode: " + strconv.Itoa(r.Rcode))
	}

	var result []NSRecord
	for _, a := range r.Answer {
		if ar, ok := a.(*dns.A); ok {
			// spew.Dump(ar)
			val := netaddr.Inet{Inet: ar.A}
			result = append(result, NSRecord{Name: a.Header().Name, Kind: "A", Value: val})
			// fmt.Printf("%s\n", mx.String())
		}
	}

	return result, nil
}