add selector, selector_query to statful_set (#293)

Author: dongho-jung

k8s-test/tests/kubernetes_stateful_set/test-get-expected.json

@@ -8,6 +8,12 @@
 		"pod_management_policy": "OrderedReady",
 		"ready_replicas": 2,
 		"replicas": 2,
+		"selector": {
+			"matchLabels": {
+				"app": "nginx"
+			}
+		},
+		"selector_query": "app=nginx",
 		"revision_history_limit": 10,
 		"service_name": "nginx",
 		"update_strategy": {

k8s-test/tests/kubernetes_stateful_set/test-get-query.sql

@@ -3,6 +3,8 @@ select
   namespace,
   service_name,
   replicas,
+  selector,
+  selector_query,
   collision_count,
   current_replicas,
   observed_generation,

kubernetes/table_kubernetes_stateful_set.go

@@ -38,6 +38,18 @@ func tableKubernetesStatefulSet(ctx context.Context) *plugin.Table {
 				Description: "The desired number of replicas of the given Template.",
 				Transform:   transform.FromField("Spec.Replicas"),
 			},
+			{
+				Name:        "selector_query",
+				Type:        proto.ColumnType_STRING,
+				Description: "A query string representation of the selector.",
+				Transform:   transform.FromField("Spec.Selector").Transform(labelSelectorToString),
+			},
+			{
+				Name:        "selector",
+				Type:        proto.ColumnType_JSON,
+				Description: "Label selector for pods. A label selector is a label query over a set of resources.",
+				Transform:   transform.FromField("Spec.Selector"),
+			},
 			{
 				Name:        "collision_count",
 				Type:        proto.ColumnType_INT,