From a38a34c7e008d4d56e9d84ed00464f45dbd680b4 Mon Sep 17 00:00:00 2001
From: Miek Gieben <miek@miek.nl>
Date: Thu, 10 Aug 2017 22:14:19 +0100
Subject: [PATCH] Kubernetes cleanup6 (#887)

* mw/kubernetes: handle dns.TypeNS better.

* mw/kubernetes: cleanup typeNS replies a bit.
---
 middleware/kubernetes/handler.go    |  2 +-
 middleware/kubernetes/kubernetes.go | 20 +++++++-------------
 middleware/kubernetes/ns_test.go    | 13 -------------
 3 files changed, 8 insertions(+), 27 deletions(-)

diff --git a/middleware/kubernetes/handler.go b/middleware/kubernetes/handler.go
index 868b39d7f..9e63ef387 100644
--- a/middleware/kubernetes/handler.go
+++ b/middleware/kubernetes/handler.go
@@ -25,7 +25,7 @@ func (k Kubernetes) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.M
 	// otherwise delegate to the next in the pipeline.
 	zone := middleware.Zones(k.Zones).Matches(state.Name())
 	if zone == "" {
-		if state.Type() != "PTR" {
+		if state.QType() != dns.TypePTR {
 			return middleware.NextOrFailure(k.Name(), k.Next, ctx, w, r)
 		}
 		// If this is a PTR request, and the request is in a defined
diff --git a/middleware/kubernetes/kubernetes.go b/middleware/kubernetes/kubernetes.go
index fce4625b6..dc20e109a 100644
--- a/middleware/kubernetes/kubernetes.go
+++ b/middleware/kubernetes/kubernetes.go
@@ -86,7 +86,6 @@ var (
 	errNoItems        = errors.New("no items found")
 	errNsNotExposed   = errors.New("namespace is not exposed")
 	errInvalidRequest = errors.New("invalid query name")
-	errZoneNotFound   = errors.New("zone not found")
 	errAPIBadPodType  = errors.New("expected type *api.Pod")
 	errPodsDisabled   = errors.New("pod records disabled")
 )
@@ -97,7 +96,7 @@ func (k *Kubernetes) Services(state request.Request, exact bool, opt middleware.
 	// We're looking again at types, which we've already done in ServeDNS, but there are some types k8s just can't answer.
 	switch state.QType() {
 	case dns.TypeTXT:
-		// 1 label + zone, label must be "dns-version"
+		// 1 label + zone, label must be "dns-version".
 		t, err := dnsutil.TrimZone(state.Name(), state.Zone)
 		if err != nil {
 			return nil, nil, err
@@ -111,6 +110,11 @@ func (k *Kubernetes) Services(state request.Request, exact bool, opt middleware.
 		}
 		svc := msg.Service{Text: DNSSchemaVersion, TTL: 28800, Key: msg.Path(state.QName(), "coredns")}
 		return []msg.Service{svc}, nil, nil
+	case dns.TypeNS:
+		// We can only get here if the qname equal the zone, see ServeDNS in handler.go.
+		ns := k.coreDNSRecord()
+		svc := msg.Service{Host: ns.A.String(), Key: msg.Path(state.QName(), "coredns")}
+		return []msg.Service{svc}, nil, nil
 	}
 
 	r, e := k.parseRequest(state.Name(), state.QType(), state.Zone)
@@ -142,20 +146,10 @@ func (k *Kubernetes) Services(state request.Request, exact bool, opt middleware.
 			}
 		}
 		return noext, nil, e
-	case dns.TypeNS:
-		srv := k.recordsForNS(r)
-		svcs = append(svcs, srv)
-		return svcs, nil, err
 	}
 	return nil, nil, nil
 }
 
-func (k *Kubernetes) recordsForNS(r recordRequest) msg.Service {
-	ns := k.coreDNSRecord()
-	return msg.Service{Host: ns.A.String(),
-		Key: msg.Path(strings.Join([]string{ns.Hdr.Name, r.zone}, "."), "coredns")}
-}
-
 // PrimaryZone will return the first non-reverse zone being handled by this middleware
 func (k *Kubernetes) PrimaryZone() string {
 	return k.Zones[k.primaryZone]
@@ -168,7 +162,7 @@ func (k *Kubernetes) Lookup(state request.Request, name string, typ uint16) (*dn
 
 // IsNameError implements the ServiceBackend interface.
 func (k *Kubernetes) IsNameError(err error) bool {
-	return err == errNoItems || err == errNsNotExposed || err == errInvalidRequest || err == errZoneNotFound
+	return err == errNoItems || err == errNsNotExposed || err == errInvalidRequest
 }
 
 // Debug implements the ServiceBackend interface.
diff --git a/middleware/kubernetes/ns_test.go b/middleware/kubernetes/ns_test.go
index b7e2ae513..e5e45afb1 100644
--- a/middleware/kubernetes/ns_test.go
+++ b/middleware/kubernetes/ns_test.go
@@ -6,19 +6,6 @@ import "net"
 import "k8s.io/client-go/1.5/pkg/api"
 import "github.com/miekg/dns"
 
-func TestRecordForNS(t *testing.T) {
-	k := Kubernetes{Zones: []string{"inter.webs.test."}}
-	corednsRecord.Hdr.Name = "coredns.kube-system."
-	corednsRecord.A = net.IP("1.2.3.4")
-	r, _ := k.parseRequest("inter.webs.test.", dns.TypeNS, "inter.webs.test.")
-
-	expected := "/coredns/test/webs/inter/kube-system/coredns"
-	svc := k.recordsForNS(r)
-	if svc.Key != expected {
-		t.Errorf("Expected  result '%v'. Instead got result '%v'.", expected, svc.Key)
-	}
-}
-
 func TestDefaultNSMsg(t *testing.T) {
 	k := Kubernetes{Zones: []string{"inter.webs.test."}}
 	corednsRecord.Hdr.Name = "coredns.kube-system."