Add k8s external service CNAMEs (#677)

* Add external service cnames

* remove cruft

* update CI k8s version

* change CI k8s version

* min k8s ver for ext services

* trying k8s 1.5

* k8s 1.5 requires ports spec

* remove kruft

* update dns schema version

5 files changed, 216 insertions, 4 deletions

diff --git a/middleware/kubernetes/README.md b/middleware/kubernetes/README.md
index 323dc9197..191bbe88e 100644
--- a/middleware/kubernetes/README.md
+++ b/middleware/kubernetes/README.md
@@ -108,6 +108,13 @@ kubernetes coredns.local {
 	#
 	cidrs 10.0.0.0/24 10.0.10.0/25
 
+	# upstream <address> [<address>] ...
+	#
+	# Defines upstream resolvers used for resolving services that point to
+	# external hosts (External Services).  <address> can be an ip, and ip:port, or
+	# a path to a file structured like resolv.conf.
+	upstream 12.34.56.78:53
+	
 	# fallthrough
 	#
 	# If a query for a record in the cluster zone results in NXDOMAIN,
diff --git a/middleware/kubernetes/kubernetes.go b/middleware/kubernetes/kubernetes.go
index e4323c3b7..5e93420e9 100644
--- a/middleware/kubernetes/kubernetes.go
+++ b/middleware/kubernetes/kubernetes.go
@@ -55,7 +55,7 @@ const (
 	// PodModeInsecure is where pod requests are answered without verfying they exist
 	PodModeInsecure = "insecure"
 	// DNSSchemaVersion is the schema version: https://github.com/kubernetes/dns/blob/master/docs/specification.md
-	DNSSchemaVersion = "1.0.0"
+	DNSSchemaVersion = "1.0.1"
 )
 
 type endpoint struct {
@@ -97,7 +97,7 @@ func (k *Kubernetes) Services(state request.Request, exact bool, opt middleware.
 	}
 
 	switch state.Type() {
-	case "A", "SRV":
+	case "A", "CNAME":
 		if state.Type() == "A" && isDefaultNS(state.Name(), r) {
 			// If this is an A request for "ns.dns", respond with a "fake" record for coredns.
 			// SOA records always use this hardcoded name
@@ -106,6 +106,16 @@ func (k *Kubernetes) Services(state request.Request, exact bool, opt middleware.
 		}
 		s, e := k.Records(r)
 		return s, nil, e // Haven't implemented debug queries yet.
+	case "SRV":
+		s, e := k.Records(r)
+		// SRV for external services is not yet implemented, so remove those records
+		noext := []msg.Service{}
+		for _, svc := range s {
+			if t, _ := svc.HostType(); t != dns.TypeCNAME {
+				noext = append(noext, svc)
+			}
+		}
+		return noext, nil, e
 	case "TXT":
 		err := k.recordsForTXT(r, &svcs)
 		return svcs, nil, err
@@ -373,6 +383,14 @@ func (k *Kubernetes) getRecordsForK8sItems(services []service, pods []pod, zone
 					Port: int(p.Port)}
 				records = append(records, s)
 			}
+			// If the addr is not an IP (i.e. an external service), add the record ...
+			s := msg.Service{
+				Key:  strings.Join([]string{zonePath, "svc", svc.namespace, svc.name}, "/"),
+				Host: svc.addr}
+			if t, _ := s.HostType(); t == dns.TypeCNAME {
+				records = append(records, s)
+			}
+
 		}
 	}
 
@@ -466,8 +484,16 @@ func (k *Kubernetes) findServices(r recordRequest) ([]service, error) {
 		if nsWildcard && (len(k.Namespaces) > 0) && (!dnsstrings.StringInSlice(svc.Namespace, k.Namespaces)) {
 			continue
 		}
-		s := service{name: svc.Name, namespace: svc.Namespace, addr: svc.Spec.ClusterIP}
-		if s.addr != api.ClusterIPNone {
+		s := service{name: svc.Name, namespace: svc.Namespace}
+		// External Service
+		if svc.Spec.ExternalName != "" {
+			s.addr = svc.Spec.ExternalName
+			resultItems = append(resultItems, s)
+			continue
+		}
+		// ClusterIP service
+		if svc.Spec.ClusterIP != api.ClusterIPNone {
+			s.addr = svc.Spec.ClusterIP
 			for _, p := range svc.Spec.Ports {
 				if !(symbolMatches(r.port, strings.ToLower(p.Name), portWildcard) && symbolMatches(r.protocol, strings.ToLower(string(p.Protocol)), protocolWildcard)) {
 					continue
@@ -478,6 +504,7 @@ func (k *Kubernetes) findServices(r recordRequest) ([]service, error) {
 			continue
 		}
 		// Headless service
+		s.addr = svc.Spec.ClusterIP
 		endpointsList := k.APIConn.EndpointsList()
 
 		for _, ep := range endpointsList.Items {
diff --git a/middleware/kubernetes/kubernetes_test.go b/middleware/kubernetes/kubernetes_test.go
index 4f748565a..f0b434cc6 100644
--- a/middleware/kubernetes/kubernetes_test.go
+++ b/middleware/kubernetes/kubernetes_test.go
@@ -9,7 +9,9 @@ import (
 	"github.com/miekg/dns"
 	"k8s.io/client-go/1.5/pkg/api"
 
+	"github.com/coredns/coredns/middleware"
 	"github.com/coredns/coredns/middleware/etcd/msg"
+	"github.com/coredns/coredns/request"
 )
 
 func TestRecordForTXT(t *testing.T) {
@@ -277,3 +279,83 @@ func TestIpFromPodName(t *testing.T) {
 		}
 	}
 }
+
+type APIConnServiceTest struct{}
+
+func (APIConnServiceTest) Run() {
+	return
+}
+
+func (APIConnServiceTest) Stop() error {
+	return nil
+}
+
+func (APIConnServiceTest) ServiceList() []*api.Service {
+	svcs := []*api.Service{
+		{
+			ObjectMeta: api.ObjectMeta{
+				Name:      "external",
+				Namespace: "testns",
+			},
+			Spec: api.ServiceSpec{
+				ExternalName: "coredns.io",
+				Ports: []api.ServicePort{{
+					Name:     "http",
+					Protocol: "tcp",
+					Port:     80,
+				}},
+			},
+		},
+	}
+	return svcs
+
+}
+
+func (APIConnServiceTest) PodIndex(string) []interface{} {
+	return nil
+}
+
+func (APIConnServiceTest) EndpointsList() api.EndpointsList {
+	return api.EndpointsList{}
+}
+
+func TestServices(t *testing.T) {
+
+	k := Kubernetes{Zones: []string{"interwebs.test"}}
+	k.APIConn = &APIConnServiceTest{}
+
+	type svcAns struct {
+		host string
+		key  string
+	}
+	type svcTest struct {
+		qname  string
+		qtype  uint16
+		answer svcAns
+	}
+	tests := []svcTest{
+		// External Services
+		{qname: "external.testns.svc.interwebs.test.", qtype: dns.TypeCNAME, answer: svcAns{host: "coredns.io", key: "/coredns/test/interwebs/svc/testns/external"}},
+	}
+
+	for _, test := range tests {
+		state := request.Request{
+			Req: &dns.Msg{Question: []dns.Question{{Name: test.qname, Qtype: test.qtype}}},
+		}
+		svcs, _, e := k.Services(state, false, middleware.Options{})
+		if e != nil {
+			t.Errorf("Query '%v' got error '%v'", test.qname, e)
+		}
+		if len(svcs) != 1 {
+			t.Errorf("Query %v %v: expected expected 1 answer, got %v", test.qname, dns.TypeToString[test.qtype], len(svcs))
+		} else {
+			if test.answer.host != svcs[0].Host {
+				t.Errorf("Query %v %v: expected host '%v', got '%v'", test.qname, dns.TypeToString[test.qtype], test.answer.host, svcs[0].Host)
+			}
+			if test.answer.key != svcs[0].Key {
+				t.Errorf("Query %v %v: expected key '%v', got '%v'", test.qname, dns.TypeToString[test.qtype], test.answer.key, svcs[0].Key)
+			}
+		}
+	}
+
+}
diff --git a/middleware/kubernetes/setup.go b/middleware/kubernetes/setup.go
index 23300733f..e143fe8a9 100644
--- a/middleware/kubernetes/setup.go
+++ b/middleware/kubernetes/setup.go
@@ -9,6 +9,8 @@ import (
 
 	"github.com/coredns/coredns/core/dnsserver"
 	"github.com/coredns/coredns/middleware"
+	"github.com/coredns/coredns/middleware/pkg/dnsutil"
+	"github.com/coredns/coredns/middleware/proxy"
 
 	"github.com/mholt/caddy"
 	unversionedapi "k8s.io/client-go/1.5/pkg/api/unversioned"
@@ -165,6 +167,16 @@ func kubernetesParse(c *caddy.Controller) (*Kubernetes, error) {
 						continue
 					}
 					return nil, c.ArgErr()
+				case "upstream":
+					args := c.RemainingArgs()
+					if len(args) == 0 {
+						return nil, c.ArgErr()
+					}
+					ups, err := dnsutil.ParseHostPortOrFile(args...)
+					if err != nil {
+						return nil, err
+					}
+					k8s.Proxy = proxy.NewLookup(ups)
 				}
 			}
 			return k8s, nil
diff --git a/middleware/kubernetes/setup_test.go b/middleware/kubernetes/setup_test.go
index f9a87a805..35cf5f891 100644
--- a/middleware/kubernetes/setup_test.go
+++ b/middleware/kubernetes/setup_test.go
@@ -28,6 +28,7 @@ func TestKubernetesParse(t *testing.T) {
 		expectedPodMode       string
 		expectedCidrs         []net.IPNet
 		expectedFallthrough   bool
+		expectedUpstreams     []string
 	}{
 		// positive
 		{
@@ -42,6 +43,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"kubernetes keyword with multiple zones",
@@ -55,6 +57,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"kubernetes keyword with zone and empty braces",
@@ -69,6 +72,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"endpoint keyword with url",
@@ -84,6 +88,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"namespaces keyword with one namespace",
@@ -99,6 +104,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"namespaces keyword with multiple namespaces",
@@ -114,6 +120,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"resync period in seconds",
@@ -129,6 +136,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"resync period in minutes",
@@ -144,6 +152,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"basic label selector",
@@ -159,6 +168,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"multi-label selector",
@@ -174,6 +184,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"fully specified valid config",
@@ -193,6 +204,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			true,
+			nil,
 		},
 		// negative
 		{
@@ -207,6 +219,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"kubernetes keyword without a zone",
@@ -220,6 +233,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"endpoint keyword without an endpoint value",
@@ -235,6 +249,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"namespace keyword without a namespace value",
@@ -250,6 +265,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"resyncperiod keyword without a duration value",
@@ -265,6 +281,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"resync period no units",
@@ -280,6 +297,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"resync period invalid",
@@ -295,6 +313,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"labels with no selector value",
@@ -310,6 +329,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		{
 			"labels with invalid selector value",
@@ -325,6 +345,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		// pods disabled
 		{
@@ -341,6 +362,7 @@ func TestKubernetesParse(t *testing.T) {
 			PodModeDisabled,
 			nil,
 			false,
+			nil,
 		},
 		// pods insecure
 		{
@@ -357,6 +379,7 @@ func TestKubernetesParse(t *testing.T) {
 			PodModeInsecure,
 			nil,
 			false,
+			nil,
 		},
 		// pods verified
 		{
@@ -373,6 +396,7 @@ func TestKubernetesParse(t *testing.T) {
 			PodModeVerified,
 			nil,
 			false,
+			nil,
 		},
 		// pods invalid
 		{
@@ -389,6 +413,7 @@ func TestKubernetesParse(t *testing.T) {
 			PodModeVerified,
 			nil,
 			false,
+			nil,
 		},
 		// cidrs ok
 		{
@@ -405,6 +430,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			[]net.IPNet{parseCidr("10.0.0.0/24"), parseCidr("10.0.1.0/24")},
 			false,
+			nil,
 		},
 		// cidrs ok
 		{
@@ -421,6 +447,7 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
 		},
 		// fallthrough invalid
 		{
@@ -437,6 +464,41 @@ func TestKubernetesParse(t *testing.T) {
 			defaultPodMode,
 			nil,
 			false,
+			nil,
+		},
+		// Valid upstream
+		{
+			"valid upstream",
+			`kubernetes coredns.local {
+	upstream 13.14.15.16:53
+}`,
+			false,
+			"",
+			1,
+			0,
+			defaultResyncPeriod,
+			"",
+			defaultPodMode,
+			nil,
+			false,
+			[]string{"13.14.15.16:53"},
+		},
+		// Invalid upstream
+		{
+			"valid upstream",
+			`kubernetes coredns.local {
+	upstream 13.14.15.16orange
+}`,
+			true,
+			"not an IP address or file: \"13.14.15.16orange\"",
+			-1,
+			0,
+			defaultResyncPeriod,
+			"",
+			defaultPodMode,
+			nil,
+			false,
+			nil,
 		},
 	}
 
@@ -515,6 +577,28 @@ func TestKubernetesParse(t *testing.T) {
 		if foundFallthrough != test.expectedFallthrough {
 			t.Errorf("Test %d: Expected kubernetes controller to be initialized with fallthrough '%v'. Instead found fallthrough '%v' for input '%s'", i, test.expectedFallthrough, foundFallthrough, test.input)
 		}
+		// upstream
+		foundUpstreams := k8sController.Proxy.Upstreams
+		if test.expectedUpstreams == nil {
+			if foundUpstreams != nil {
+				t.Errorf("Test %d: Expected kubernetes controller to not be initialized with upstreams for input '%s'", i, test.input)
+			}
+		} else {
+			if foundUpstreams == nil {
+				t.Errorf("Test %d: Expected kubernetes controller to be initialized with upstreams for input '%s'", i, test.input)
+			} else {
+				if len(*foundUpstreams) != len(test.expectedUpstreams) {
+					t.Errorf("Test %d: Expected kubernetes controller to be initialized with %d upstreams. Instead found %d upstreams for input '%s'", i, len(test.expectedUpstreams), len(*foundUpstreams), test.input)
+				}
+				for j, want := range test.expectedUpstreams {
+					got := (*foundUpstreams)[j].Select().Name
+					if got != want {
+						t.Errorf("Test %d: Expected kubernetes controller to be initialized with upstream '%s'. Instead found upstream '%s' for input '%s'", i, want, got, test.input)
+					}
+				}
+
+			}
+		}
 
 	}
 }