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package main
import (
type Request struct {
DomainName string `json:"name"`
Type string `json:"type"`
type Response struct {
Name string `json:"name"`
Value string `json:"value"`
Type string `json:"type"`
TTL uint32 `json:"ttl"`
func handler(request events.APIGatewayProxyRequest) (*events.APIGatewayProxyResponse, error) {
if request.HTTPMethod != "POST" {
return &events.APIGatewayProxyResponse{
StatusCode: 200,
Headers: map[string]string{
"Content-Type": "application/json",
"Access-Control-Allow-Origin": "*",
"Access-Control-Allow-Headers": "*",
}, nil
var req Request
if err := json.NewDecoder(strings.NewReader(request.Body)).Decode(&req); err != nil {
return &events.APIGatewayProxyResponse{
StatusCode: 500,
Body: fmt.Sprintf("Failed to parse payload: %v", err),
}, nil
var results *[]Response
var err error
if results, err = query(req.Type, req.DomainName); err != nil {
return &events.APIGatewayProxyResponse{
StatusCode: 500,
Body: fmt.Sprintf("Failed to make DNS request: %v", err),
}, nil
output, err := json.Marshal(results)
return &events.APIGatewayProxyResponse{
StatusCode: 200,
Headers: map[string]string{
"Content-Type": "application/json",
"Access-Control-Allow-Origin": "*",
"Access-Control-Allow-Headers": "*",
Body: string(output),
IsBase64Encoded: false,
}, nil
func message(typ string, name string) *dns.Msg {
recs := map[string]uint16{
"a": dns.TypeA,
"aaaa": dns.TypeAAAA,
"cname": dns.TypeCNAME,
"mx": dns.TypeMX,
"ns": dns.TypeNS,
"ptr": dns.TypePTR,
"soa": dns.TypeSOA,
"srv": dns.TypeSRV,
"txt": dns.TypeTXT,
"dnskey": dns.TypeDNSKEY,
"ds": dns.TypeDS,
"nsec": dns.TypeNSEC,
"nsec3": dns.TypeNSEC3,
"rrsig": dns.TypeRRSIG,
"afsdb": dns.TypeAFSDB,
"atma": dns.TypeATMA,
"caa": dns.TypeCAA,
"cert": dns.TypeCERT,
"dhcid": dns.TypeDHCID,
"dname": dns.TypeDNAME,
"hinfo": dns.TypeHINFO,
"isdn": dns.TypeISDN,
"loc": dns.TypeLOC,
"mb": dns.TypeMB,
"mg": dns.TypeMG,
"minfo": dns.TypeMINFO,
"mr": dns.TypeMR,
"naptr": dns.TypeNAPTR,
"nsapptr": dns.TypeNSAPPTR,
"rp": dns.TypeRP,
"rt": dns.TypeRT,
"tlsa": dns.TypeTLSA,
"x25": dns.TypeX25,
m := new(dns.Msg)
m.Id = dns.Id()
m.RecursionDesired = true
m.Question = make([]dns.Question, 1)
m.Question[0] = dns.Question{name, recs[typ], dns.ClassINET}
return m
func query(typ string, name string) (*[]Response, error) {
message := message(typ, name)
c := new(dns.Client)
in, _, err := c.Exchange(message, "")
if err != nil {
return nil, err
replies := make([]Response, 0)
for _, a := range in.Answer {
h := a.Header()
parts := strings.Split(a.String(), "\t")
replies = append(replies, Response{
Value: parts[len(parts)-1],
Name: h.Name,
TTL: h.Ttl,
Type: dns.Type(h.Rrtype).String(),
return &replies, nil
func main() {
// Make the handler available for Remote Procedure Call by AWS Lambda
replies, _ := query("a", "")
for _, a := range *replies {