Stop hardcoding things

Signed-off-by: Miek Gieben <miek@miek.nl>

plugin/traffic/traffic.go

@@ -2,6 +2,8 @@ package traffic
 
 import (
 	"context"
+	"strings"
+	"time"
 
 	"github.com/coredns/coredns/plugin"
 	"github.com/coredns/coredns/plugin/pkg/dnsutil"
@@ -13,9 +15,10 @@ import (
 
 // Traffic is a plugin that load balances according to assignments.
 type Traffic struct {
-	c    *xds.Client
-	id   string
-	Next plugin.Handler
+	c       *xds.Client
+	id      string
+	origins []string
+	Next    plugin.Handler
 }
 
 // shutdown closes the connection to the managment endpoints and stops any running goroutines.
@@ -25,26 +28,71 @@ func (t *Traffic) shutdown() { t.c.Close() }
 func (t *Traffic) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
 	state := request.Request{Req: r, W: w}
 
-	cluster, _ := dnsutil.TrimZone(state.Name(), "example.org")
-	addr := t.c.Select(cluster)
-	if addr == nil {
+	cluster := ""
+	for _, o := range t.origins {
+		println(o, state.Name())
+		if strings.HasSuffix(state.Name(), o) {
+			cluster, _ = dnsutil.TrimZone(state.Name(), o)
+			state.Zone = o
+			break
+		}
+	}
+	if cluster == "" {
+		// TODO(miek): can this actually happen?
 		return plugin.NextOrFailure(t.Name(), t.Next, ctx, w, r)
 	}
 
-	log.Debugf("Found address %q for %q", addr, cluster)
+	addr := t.c.Select(cluster)
+	if addr != nil {
+		log.Debugf("Found endpoint %q for %q", addr, cluster)
+	} else {
+		log.Debugf("No healthy endpoints found for %q", cluster)
+	}
 
-	// assemble reply
 	m := new(dns.Msg)
 	m.SetReply(r)
 
-	m.Answer = []dns.RR{&dns.A{
-		Hdr: dns.RR_Header{Name: state.QName(), Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 5},
-		A:   addr,
-	}}
+	if addr == nil {
+		m.Ns = soa(state.Zone)
+		w.WriteMsg(m)
+		return 0, nil
+	}
+
+	switch state.QType() {
+	case dns.TypeA:
+		if addr.To4() == nil { // it's an IPv6 address, return nodata in that case.
+			m.Ns = soa(state.Zone)
+			break
+		}
+		m.Answer = []dns.RR{&dns.A{Hdr: dns.RR_Header{Name: state.QName(), Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 5}, A: addr}}
+
+	case dns.TypeAAAA:
+		if addr.To4() != nil { // it's an IPv4 address, return nodata in that case.
+			m.Ns = soa(state.Zone)
+			break
+		}
+		m.Answer = []dns.RR{&dns.AAAA{Hdr: dns.RR_Header{Name: state.QName(), Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 5}, AAAA: addr}}
+	default:
+		m.Ns = soa(state.Zone)
+	}
 
 	w.WriteMsg(m)
 	return 0, nil
 }
 
+// soa returns a synthetic so for this zone.
+func soa(z string) []dns.RR {
+	return []dns.RR{&dns.SOA{
+		Hdr:     dns.RR_Header{Name: z, Rrtype: dns.TypeSOA, Class: dns.ClassINET, Ttl: 5},
+		Ns:      dnsutil.Join("ns", z),
+		Mbox:    dnsutil.Join("coredns", z),
+		Serial:  uint32(time.Now().UTC().Unix()),
+		Refresh: 14400,
+		Retry:   3600,
+		Expire:  604800,
+		Minttl:  5,
+	}}
+}
+
 // Name implements the plugin.Handler interface.
 func (t *Traffic) Name() string { return "traffic" }