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

middleware/kubernetes/kubernetes.go

@@ -112,7 +112,7 @@ func (k *Kubernetes) Services(state request.Request, exact bool, opt middleware.
 		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()
+		ns := k.nsAddr()
 		svc := msg.Service{Host: ns.A.String(), Key: msg.Path(state.QName(), "coredns")}
 		return []msg.Service{svc}, nil, nil
 	}

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."

middleware/kubernetes/ns_test.go

 package kubernetes
 
-import "testing"
-import "net"
+import (
+	"net"
+	"testing"
 
-import "k8s.io/client-go/1.5/pkg/api"
-import "github.com/miekg/dns"
-
-func TestDefaultNSMsg(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("ns.dns.inter.webs.test.", dns.TypeA, "inter.webs.test.")
-
-	expected := "/coredns/test/webs/inter/dns/ns"
-	svc := k.defaultNSMsg(r)
-	if svc.Key != expected {
-		t.Errorf("Expected  result '%v'. Instead got result '%v'.", expected, svc.Key)
-	}
-}
-
-func TestIsDefaultNS(t *testing.T) {
-	k := Kubernetes{Zones: []string{"inter.webs.test."}}
-	r, _ := k.parseRequest("ns.dns.inter.webs.test", dns.TypeA, "inter.webs.test.")
-
-	var name string
-	var expected bool
-
-	name = "ns.dns.inter.webs.test."
-	expected = true
-	if isDefaultNS(name, r) != expected {
-		t.Errorf("Expected IsDefaultNS('%v') to be '%v'.", name, expected)
-	}
-	name = "ns.dns.blah.inter.webs.test"
-	expected = false
-	if isDefaultNS(name, r) != expected {
-		t.Errorf("Expected IsDefaultNS('%v') to be '%v'.", name, expected)
-	}
-}
+	"k8s.io/client-go/1.5/pkg/api"
+)
 
 type APIConnTest struct{}
 
@@ -83,24 +52,20 @@ func (APIConnTest) EndpointsList() api.EndpointsList {
 
 func (APIConnTest) GetNodeByName(name string) (api.Node, error) { return api.Node{}, nil }
 
-func TestDoCoreDNSRecord(t *testing.T) {
+func TestNsAddr(t *testing.T) {
 
-	corednsRecord = dns.A{}
 	k := Kubernetes{Zones: []string{"inter.webs.test"}}
-
 	k.interfaceAddrsFunc = func() net.IP { return net.ParseIP("172.0.40.10") }
-
 	k.APIConn = &APIConnTest{}
 
-	cdr := k.coreDNSRecord()
-
+	cdr := k.nsAddr()
 	expected := "10.0.0.111"
 
 	if cdr.A.String() != expected {
-		t.Errorf("Expected A to be '%v', got '%v'", expected, cdr.A.String())
+		t.Errorf("Expected A to be %q, got %q", expected, cdr.A.String())
 	}
 	expected = "dns-service.kube-system.svc."
 	if cdr.Hdr.Name != expected {
-		t.Errorf("Expected Hdr.Name to be '%v', got '%v'", expected, cdr.Hdr.Name)
+		t.Errorf("Expected Hdr.Name to be %q, got %q", expected, cdr.Hdr.Name)
 	}
 }