kubectl: Remove duplicate selector calculation logic and add missing test cases for the 'describe DaemonSet' functionality

Author: icylord

staging/src/k8s.io/kubectl/pkg/describe/describe.go

@@ -2527,18 +2527,14 @@ func (d *DaemonSetDescriber) Describe(namespace, name string, describerSettings
 		events, _ = searchEvents(d.CoreV1(), daemon, describerSettings.ChunkSize)
 	}
 
-	return describeDaemonSet(daemon, events, running, waiting, succeeded, failed)
+	return describeDaemonSet(daemon, selector, events, running, waiting, succeeded, failed)
 }
 
-func describeDaemonSet(daemon *appsv1.DaemonSet, events *corev1.EventList, running, waiting, succeeded, failed int) (string, error) {
+func describeDaemonSet(daemon *appsv1.DaemonSet, selector labels.Selector, events *corev1.EventList, running, waiting, succeeded, failed int) (string, error) {
 	return tabbedString(func(out io.Writer) error {
 		w := NewPrefixWriter(out)
 		w.Write(LEVEL_0, "Name:\t%s\n", daemon.Name)
-		selector, err := metav1.LabelSelectorAsSelector(daemon.Spec.Selector)
-		if err != nil {
-			// this shouldn't happen if LabelSelector passed validation
-			return err
-		}
+		w.Write(LEVEL_0, "Namespace:\t%s\n", daemon.Namespace)
 		w.Write(LEVEL_0, "Selector:\t%s\n", selector)
 		w.Write(LEVEL_0, "Node-Selector:\t%s\n", labels.FormatLabels(daemon.Spec.Template.Spec.NodeSelector))
 		printLabelsMultiline(w, "Labels", daemon.Labels)

staging/src/k8s.io/kubectl/pkg/describe/describe_test.go

@@ -6397,6 +6397,41 @@ func TestDescribeStatefulSet(t *testing.T) {
 	}
 }
 
+func TestDescribeDaemonSet(t *testing.T) {
+	fake := fake.NewSimpleClientset(&appsv1.DaemonSet{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "bar",
+			Namespace: "foo",
+		},
+		Spec: appsv1.DaemonSetSpec{
+			Selector: &metav1.LabelSelector{
+				MatchLabels: map[string]string{"node-role.kubernetes.io/control-plane": "true"},
+			},
+			Template: corev1.PodTemplateSpec{
+				Spec: corev1.PodSpec{
+					Containers: []corev1.Container{
+						{Image: "mytest-image:latest"},
+					},
+				},
+			},
+		},
+	})
+	d := DaemonSetDescriber{fake}
+	out, err := d.Describe("foo", "bar", DescriberSettings{ShowEvents: true})
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	expectedOutputs := []string{
+		"bar", "foo", "Containers:", "mytest-image:latest", "Selector", "node-role.kubernetes.io/control-plane=true",
+	}
+	for _, o := range expectedOutputs {
+		if !strings.Contains(out, o) {
+			t.Errorf("unexpected out: %s", out)
+			break
+		}
+	}
+}
+
 func TestDescribeEndpointSlice(t *testing.T) {
 	protocolTCP := corev1.ProtocolTCP
 	port80 := int32(80)