Add metav1.SetMetaDataLabel func

Signed-off-by: ialidzhikov <i.alidjikov@gmail.com>

staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/helpers.go

@@ -201,6 +201,20 @@ func SetMetaDataAnnotation(obj *ObjectMeta, ann string, value string) {
 	obj.Annotations[ann] = value
 }
 
+// HasLabel returns a bool if passed in label exists
+func HasLabel(obj ObjectMeta, label string) bool {
+	_, found := obj.Labels[label]
+	return found
+}
+
+// SetMetaDataLabel sets the label and value
+func SetMetaDataLabel(obj *ObjectMeta, label string, value string) {
+	if obj.Labels == nil {
+		obj.Labels = make(map[string]string)
+	}
+	obj.Labels[label] = value
+}
+
 // SingleObject returns a ListOptions for watching a single object.
 func SingleObject(meta ObjectMeta) ListOptions {
 	return ListOptions{

staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/helpers_test.go

@@ -195,3 +195,38 @@ func TestResetObjectMetaForStatus(t *testing.T) {
 		t.Error(diff.ObjectDiff(meta, existingMeta))
 	}
 }
+
+func TestSetMetaDataLabel(t *testing.T) {
+	tests := []struct {
+		obj   *ObjectMeta
+		label string
+		value string
+		want  map[string]string
+	}{
+		{
+			obj:   &ObjectMeta{},
+			label: "foo",
+			value: "bar",
+			want:  map[string]string{"foo": "bar"},
+		},
+		{
+			obj:   &ObjectMeta{Labels: map[string]string{"foo": "bar"}},
+			label: "foo",
+			value: "baz",
+			want:  map[string]string{"foo": "baz"},
+		},
+		{
+			obj:   &ObjectMeta{Labels: map[string]string{"foo": "bar"}},
+			label: "version",
+			value: "1.0.0",
+			want:  map[string]string{"foo": "bar", "version": "1.0.0"},
+		},
+	}
+
+	for _, tc := range tests {
+		SetMetaDataLabel(tc.obj, tc.label, tc.value)
+		if !reflect.DeepEqual(tc.obj.Labels, tc.want) {
+			t.Errorf("got %v, want %v", tc.obj.Labels, tc.want)
+		}
+	}
+}