63 lines
1.2 KiB
Go
63 lines
1.2 KiB
Go
// Package dns resolves names to dns records
|
|
package dns
|
|
|
|
import (
|
|
"context"
|
|
"net"
|
|
|
|
"github.com/micro/go-micro/network/resolver"
|
|
"github.com/miekg/dns"
|
|
)
|
|
|
|
// Resolver is a DNS network resolve
|
|
type Resolver struct {
|
|
// The resolver address to use
|
|
Address string
|
|
}
|
|
|
|
// Resolve assumes ID is a domain name e.g micro.mu
|
|
func (r *Resolver) Resolve(name string) ([]*resolver.Record, error) {
|
|
host, port, err := net.SplitHostPort(name)
|
|
if err != nil {
|
|
host = name
|
|
port = "8085"
|
|
}
|
|
|
|
if len(host) == 0 {
|
|
host = "localhost"
|
|
}
|
|
|
|
if len(r.Address) == 0 {
|
|
r.Address = "1.0.0.1:53"
|
|
}
|
|
|
|
m := new(dns.Msg)
|
|
m.SetQuestion(dns.Fqdn(host), dns.TypeA)
|
|
rec, err := dns.ExchangeContext(context.Background(), m, r.Address)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
var records []*resolver.Record
|
|
|
|
for _, answer := range rec.Answer {
|
|
h := answer.Header()
|
|
// check record type matches
|
|
if h.Rrtype != dns.TypeA {
|
|
continue
|
|
}
|
|
|
|
arec, _ := answer.(*dns.A)
|
|
addr := arec.A.String()
|
|
|
|
// join resolved record with port
|
|
address := net.JoinHostPort(addr, port)
|
|
// append to record set
|
|
records = append(records, &resolver.Record{
|
|
Address: address,
|
|
})
|
|
}
|
|
|
|
return records, nil
|
|
}
|