update lease store to export namespace

Author: lantingchiang

docs/lease-metrics.md

@@ -3,4 +3,4 @@
 | Metric name| Metric type | Labels/tags                                                                                                                               | Status |
 | ---------- | ----------- |-------------------------------------------------------------------------------------------------------------------------------------------| ----------- |
 | kube_lease_owner | Gauge | `lease`=&lt;lease-name&gt; <br> `owner_kind`=&lt;onwer kind&gt; <br> `owner_name`=&lt;owner name&gt; <br> `namespace` = &lt;namespace&gt; | EXPERIMENTAL |
-| kube_lease_renew_time | Gauge | `lease`=&lt;lease-name&gt; <br> `namespace` = &lt;namespace&gt;                                                                                                               | EXPERIMENTAL |
+| kube_lease_renew_time | Gauge | `lease`=&lt;lease-name&gt;                                                                                                              | EXPERIMENTAL |

internal/store/lease.go

@@ -40,15 +40,15 @@ var (
 			metric.Gauge,
 			"",
 			wrapLeaseFunc(func(l *coordinationv1.Lease) *metric.Family {
-				labelKeys := []string{"owner_kind", "owner_name"}
+				labelKeys := []string{"owner_kind", "owner_name", "namespace"}
 
 				owners := l.GetOwnerReferences()
 				if len(owners) == 0 {
 					return &metric.Family{
 						Metrics: []*metric.Metric{
 							{
 								LabelKeys:   labelKeys,
-								LabelValues: []string{"<none>", "<none>"},
+								LabelValues: []string{"<none>", "<none>", l.Namespace},
 								Value:       1,
 							},
 						},
@@ -59,7 +59,7 @@ var (
 				for i, owner := range owners {
 					ms[i] = &metric.Metric{
 						LabelKeys:   labelKeys,
-						LabelValues: []string{owner.Kind, owner.Name},
+						LabelValues: []string{owner.Kind, owner.Name, l.Namespace},
 						Value:       1,
 					}
 				}

internal/store/lease_test.go

@@ -41,6 +41,7 @@ func TestLeaseStore(t *testing.T) {
 					ObjectMeta: metav1.ObjectMeta{
 						Generation:        2,
 						Name:              "kube-master",
+						Namespace:         "default",
 						CreationTimestamp: metav1.Time{Time: time.Unix(1500000000, 0)},
 						OwnerReferences: []metav1.OwnerReference{
 							{
@@ -54,7 +55,7 @@ func TestLeaseStore(t *testing.T) {
 					},
 				},
 				Want: metadata + `
-                    kube_lease_owner{lease="kube-master",owner_kind="Node",owner_name="kube-master"} 1
+                    kube_lease_owner{lease="kube-master",owner_kind="Node",owner_name="kube-master",namespace="default"} 1
                     kube_lease_renew_time{lease="kube-master"} 1.5e+09
 			`,
 				MetricNames: []string{