Fix k8s PTR when all namespaces exposed (#507)

* check for no namespace filter

* integration test

middleware/kubernetes/kubernetes.go

@@ -508,7 +508,7 @@ func (k *Kubernetes) getServiceRecordForIP(ip, name string) []msg.Service {
 		return nil
 	}
 	for _, service := range svcList {
-		if !dnsstrings.StringInSlice(service.Namespace, k.Namespaces) {
+		if (len(k.Namespaces) > 0) && !dnsstrings.StringInSlice(service.Namespace, k.Namespaces) {
 			continue
 		}
 		if service.Spec.ClusterIP == ip {
@@ -522,7 +522,7 @@ func (k *Kubernetes) getServiceRecordForIP(ip, name string) []msg.Service {
 		return nil
 	}
 	for _, ep := range epList.Items {
-		if !dnsstrings.StringInSlice(ep.ObjectMeta.Namespace, k.Namespaces) {
+		if (len(k.Namespaces) > 0) && !dnsstrings.StringInSlice(ep.ObjectMeta.Namespace, k.Namespaces) {
 			continue
 		}
 		for _, eps := range ep.Subsets {

test/kubernetes_test.go

@@ -315,6 +315,42 @@ var dnsTestCasesPartialCidrReverseZone = []test.Case{
 	},
 }
 
+var dnsTestCasesAllNSExposed = []test.Case{
+	{
+		Qname: "svc-1-a.test-1.svc.cluster.local.", Qtype: dns.TypeA,
+		Rcode: dns.RcodeSuccess,
+		Answer: []dns.RR{
+			test.A("svc-1-a.test-1.svc.cluster.local.      303    IN      A       10.0.0.100"),
+		},
+	},
+	{
+		Qname: "svc-c.test-2.svc.cluster.local.", Qtype: dns.TypeA,
+		Rcode: dns.RcodeSuccess,
+		Answer: []dns.RR{
+			test.A("svc-c.test-1.svc.cluster.local.      303    IN      A       10.0.0.120"),
+		},
+	},
+	{
+		Qname: "123.0.0.10.in-addr.arpa.", Qtype: dns.TypePTR,
+		Rcode:  dns.RcodeSuccess,
+		Answer: []dns.RR{},
+	},
+	{
+		Qname: "100.0.0.10.in-addr.arpa.", Qtype: dns.TypePTR,
+		Rcode: dns.RcodeSuccess,
+		Answer: []dns.RR{
+			test.PTR("100.0.0.10.in-addr.arpa.      303    IN      PTR       svc-1-a.test-1.svc.cluster.local."),
+		},
+	},
+	{
+		Qname: "120.0.0.10.in-addr.arpa.", Qtype: dns.TypePTR,
+		Rcode: dns.RcodeSuccess,
+		Answer: []dns.RR{
+			test.PTR("120.0.0.10.in-addr.arpa.      303    IN      PTR       svc-c.test-2.svc.cluster.local."),
+		},
+	},
+}
+
 func createTestServer(t *testing.T, corefile string) (*caddy.Instance, string) {
 	server, err := CoreDNSServer(corefile)
 	if err != nil {
@@ -424,3 +460,14 @@ func TestKubernetesIntegrationPartialCidrReverseZone(t *testing.T) {
 `
 	doIntegrationTests(t, corefile, dnsTestCasesPartialCidrReverseZone)
 }
+
+func TestKubernetesIntegrationAllNSExposed(t *testing.T) {
+	corefile :=
+		`.:0 {
+    kubernetes cluster.local {
+                endpoint http://localhost:8080
+				cidrs 10.0.0.0/24
+    }
+`
+	doIntegrationTests(t, corefile, dnsTestCasesAllNSExposed)
+}