Fix bug with empty subsets

pkg/registry/service/rest.go

@@ -295,6 +295,9 @@ func (rs *REST) ResourceLocation(ctx api.Context, id string) (*url.URL, http.Rou
 	// Find a Subset that has the port.
 	for ssi := 0; ssi < len(eps.Subsets); ssi++ {
 		ss := &eps.Subsets[(ssSeed+ssi)%len(eps.Subsets)]
+		if len(ss.Addresses) == 0 {
+			continue
+		}
 		for i := range ss.Ports {
 			if ss.Ports[i].Name == portStr {
 				// Pick a random address.

pkg/registry/service/rest_test.go

@@ -440,6 +440,22 @@ func TestServiceRegistryResourceLocation(t *testing.T) {
 					Ports:     []api.EndpointPort{{Name: "", Port: 80}, {Name: "p", Port: 93}},
 				}},
 			},
+			{
+				ObjectMeta: api.ObjectMeta{
+					Name:      "foo",
+					Namespace: api.NamespaceDefault,
+				},
+				Subsets: []api.EndpointSubset{{
+					Addresses: []api.EndpointAddress{},
+					Ports:     []api.EndpointPort{{Name: "", Port: 80}, {Name: "p", Port: 93}},
+				}, {
+					Addresses: []api.EndpointAddress{{IP: "1.2.3.4"}},
+					Ports:     []api.EndpointPort{{Name: "", Port: 80}, {Name: "p", Port: 93}},
+				}, {
+					Addresses: []api.EndpointAddress{{IP: "1.2.3.5"}},
+					Ports:     []api.EndpointPort{},
+				}},
+			},
 		},
 	}
 	storage, registry := NewTestREST(t, endpoints)