mw/k8s: remove dependence on global var (#888)

* mw/k8s: remove dependence on global var

Remove the global coreDNSRecord that was used. Remove tests the
referenced that var. Cleanup the rest.

* Rename function as well

* fixes

1 files changed, 38 insertions, 44 deletions

diff --git a/middleware/kubernetes/ns.go b/middleware/kubernetes/ns.go
index d14a1e96d..8f521e36a 100644
--- a/middleware/kubernetes/ns.go
+++ b/middleware/kubernetes/ns.go
@@ -10,15 +10,11 @@ import (
 	"k8s.io/client-go/1.5/pkg/api"
 )
 
-const defaultNSName = "ns.dns."
-
-var corednsRecord dns.A
-
 // DefaultNSMsg returns an msg.Service representing an A record for
 // ns.dns.[zone] -> dns service ip. This A record is needed to legitimize
 // the SOA response in middleware.NS(), which is hardcoded at ns.dns.[zone].
 func (k *Kubernetes) defaultNSMsg(r recordRequest) msg.Service {
-	ns := k.coreDNSRecord()
+	ns := k.nsAddr()
 	s := msg.Service{
 		Key:  msg.Path(strings.Join([]string{defaultNSName, r.zone}, "."), "coredns"),
 		Host: ns.A.String(),
@@ -30,57 +26,55 @@ func isDefaultNS(name string, r recordRequest) bool {
 	return strings.Index(name, defaultNSName) == 0 && strings.Index(name, r.zone) == len(defaultNSName)
 }
 
-func (k *Kubernetes) coreDNSRecord() dns.A {
+func (k *Kubernetes) nsAddr() *dns.A {
 	var (
 		svcName      string
 		svcNamespace string
-		dnsIP        net.IP
 	)
 
-	if len(corednsRecord.Hdr.Name) == 0 || corednsRecord.A == nil {
-		// get local Pod IP
-		localIP := k.interfaceAddrsFunc()
-		// Find endpoint matching IP to get service and namespace
-		endpointsList := k.APIConn.EndpointsList()
+	rr := new(dns.A)
+	localIP := k.interfaceAddrsFunc()
+	endpointsList := k.APIConn.EndpointsList()
+
+	rr.A = localIP
 
-	FindEndpoint:
-		for _, ep := range endpointsList.Items {
-			for _, eps := range ep.Subsets {
-				for _, addr := range eps.Addresses {
-					if localIP.Equal(net.ParseIP(addr.IP)) {
+FindEndpoint:
+	for _, ep := range endpointsList.Items {
+		for _, eps := range ep.Subsets {
+			for _, addr := range eps.Addresses {
+				if localIP.Equal(net.ParseIP(addr.IP)) {
 
-						svcNamespace = ep.ObjectMeta.Namespace
-						svcName = ep.ObjectMeta.Name
-						break FindEndpoint
-					}
+					svcNamespace = ep.ObjectMeta.Namespace
+					svcName = ep.ObjectMeta.Name
+					break FindEndpoint
 				}
 			}
 		}
+	}
 
-		if len(svcName) == 0 {
-			corednsRecord.Hdr.Name = defaultNSName
-			corednsRecord.A = localIP
-			return corednsRecord
-		}
-		// Find service to get ClusterIP
-		serviceList := k.APIConn.ServiceList()
-	FindService:
-		for _, svc := range serviceList {
-			if svcName == svc.Name && svcNamespace == svc.Namespace {
-				if svc.Spec.ClusterIP == api.ClusterIPNone {
-					dnsIP = localIP
-				} else {
-					dnsIP = net.ParseIP(svc.Spec.ClusterIP)
-				}
-				break FindService
+	if len(svcName) == 0 {
+		rr.Hdr.Name = defaultNSName
+		rr.A = localIP
+		return rr
+	}
+	// Find service to get ClusterIP
+	serviceList := k.APIConn.ServiceList()
+
+FindService:
+	for _, svc := range serviceList {
+		if svcName == svc.Name && svcNamespace == svc.Namespace {
+			if svc.Spec.ClusterIP == api.ClusterIPNone {
+				rr.A = localIP
+			} else {
+				rr.A = net.ParseIP(svc.Spec.ClusterIP)
 			}
+			break FindService
 		}
-		if dnsIP == nil {
-			dnsIP = localIP
-		}
-
-		corednsRecord.Hdr.Name = strings.Join([]string{svcName, svcNamespace, "svc."}, ".")
-		corednsRecord.A = dnsIP
 	}
-	return corednsRecord
+
+	rr.Hdr.Name = strings.Join([]string{svcName, svcNamespace, "svc."}, ".")
+
+	return rr
 }
+
+const defaultNSName = "ns.dns."