Add metadata getters and setters to RNode.

These setters completely remove the field if the argument
is empty, rather than setting the field to an empty value,
mimicing apimachinery behavior.

kyaml/yaml/rnode.go

@@ -333,6 +333,88 @@ func (rn *RNode) SetYNode(node *yaml.Node) {
 	*rn.value = *node
 }
 
+// GetNamespace gets the metadata namespace field.
+func (rn *RNode) GetNamespace() (string, error) {
+	meta, err := rn.GetMeta()
+	if err != nil {
+		return "", err
+	}
+	return meta.Namespace, nil
+}
+
+// SetNamespace tries to set the metadata namespace field.
+func (rn *RNode) SetNamespace(ns string) error {
+	meta, err := rn.Pipe(Lookup(MetadataField))
+	if err != nil {
+		return err
+	}
+	if ns == "" {
+		if rn == nil {
+			return nil
+		}
+		return meta.PipeE(Clear(NamespaceField))
+	}
+	return rn.SetMapField(
+		NewScalarRNode(ns), MetadataField, NamespaceField)
+}
+
+// GetAnnotations gets the metadata annotations field.
+func (rn *RNode) GetAnnotations() (map[string]string, error) {
+	meta, err := rn.GetMeta()
+	if err != nil {
+		return nil, err
+	}
+	return meta.Annotations, nil
+}
+
+// SetAnnotations tries to set the metadata annotations field.
+func (rn *RNode) SetAnnotations(m map[string]string) error {
+	meta, err := rn.Pipe(Lookup(MetadataField))
+	if err != nil {
+		return err
+	}
+	if len(m) == 0 {
+		if meta == nil {
+			return nil
+		}
+		return meta.PipeE(Clear(AnnotationsField))
+	}
+	return rn.SetMapField(
+		NewMapRNode(&m), MetadataField, AnnotationsField)
+}
+
+// GetLabels gets the metadata labels field.
+func (rn *RNode) GetLabels() (map[string]string, error) {
+	meta, err := rn.GetMeta()
+	if err != nil {
+		return nil, err
+	}
+	return meta.Labels, nil
+}
+
+// SetLabels sets the metadata labels field.
+func (rn *RNode) SetLabels(m map[string]string) error {
+	meta, err := rn.Pipe(Lookup(MetadataField))
+	if err != nil {
+		return err
+	}
+	if len(m) == 0 {
+		if meta == nil {
+			return nil
+		}
+		return meta.PipeE(Clear(LabelsField))
+	}
+	return rn.SetMapField(
+		NewMapRNode(&m), MetadataField, LabelsField)
+}
+
+func (rn *RNode) SetMapField(value *RNode, path ...string) error {
+	return rn.PipeE(
+		LookupCreate(yaml.MappingNode, path[0:len(path)-1]...),
+		SetField(path[len(path)-1], value),
+	)
+}
+
 // AppendToFieldPath appends a field name to the FieldPath.
 func (rn *RNode) AppendToFieldPath(parts ...string) {
 	rn.fieldPath = append(rn.fieldPath, parts...)

kyaml/yaml/rnode_test.go

@@ -751,3 +751,104 @@ func TestRNodeIsNilOrEmpty(t *testing.T) {
 		t.Fatalf("non-empty list should not be empty")
 	}
 }
+
+const deploymentJSON = `
+{
+  "apiVersion": "apps/v1",
+  "kind": "Deployment",
+  "metadata": {
+    "name": "homer",
+    "namespace": "simpsons",
+    "labels": {
+      "fruit": "apple",
+      "veggie": "carrot"
+    },
+    "annotations": {
+      "area": "51",
+      "greeting": "Take me to your leader."
+    }
+  }
+}
+`
+
+func getNamespaceOrDie(t *testing.T, n *RNode) string {
+	m, err := n.GetNamespace()
+	assert.NoError(t, err)
+	return m
+}
+
+func TestRNodeSetNamespace(t *testing.T) {
+	n := NewRNode(nil)
+	assert.Equal(t, "", getNamespaceOrDie(t, n))
+	assert.NoError(t, n.SetNamespace(""))
+	assert.Equal(t, "", getNamespaceOrDie(t, n))
+	if err := n.UnmarshalJSON([]byte(deploymentJSON)); err != nil {
+		t.Fatalf("unexpected unmarshaljson err: %v", err)
+	}
+	assert.NoError(t, n.SetNamespace("flanders"))
+	assert.Equal(t, "flanders", getNamespaceOrDie(t, n))
+}
+
+func getLabelsOrDie(t *testing.T, n *RNode) map[string]string {
+	m, err := n.GetLabels()
+	assert.NoError(t, err)
+	return m
+}
+
+func TestRNodeSetLabels(t *testing.T) {
+	n := NewRNode(nil)
+	assert.Equal(t, 0, len(getLabelsOrDie(t, n)))
+	assert.NoError(t, n.SetLabels(map[string]string{}))
+	assert.Equal(t, 0, len(getLabelsOrDie(t, n)))
+
+	n = NewRNode(nil)
+	if err := n.UnmarshalJSON([]byte(deploymentJSON)); err != nil {
+		t.Fatalf("unexpected unmarshaljson err: %v", err)
+	}
+	labels := getLabelsOrDie(t, n)
+	assert.Equal(t, 2, len(labels))
+	assert.Equal(t, "apple", labels["fruit"])
+	assert.Equal(t, "carrot", labels["veggie"])
+	assert.NoError(t, n.SetLabels(map[string]string{
+		"label1": "foo",
+		"label2": "bar",
+	}))
+	labels = getLabelsOrDie(t, n)
+	assert.Equal(t, 2, len(labels))
+	assert.Equal(t, "foo", labels["label1"])
+	assert.Equal(t, "bar", labels["label2"])
+	assert.NoError(t, n.SetLabels(map[string]string{}))
+	assert.Equal(t, 0, len(getLabelsOrDie(t, n)))
+}
+
+func getAnnotationsOrDie(t *testing.T, n *RNode) map[string]string {
+	m, err := n.GetAnnotations()
+	assert.NoError(t, err)
+	return m
+}
+
+func TestRNodeGetAnnotations(t *testing.T) {
+	n := NewRNode(nil)
+	assert.Equal(t, 0, len(getAnnotationsOrDie(t, n)))
+	assert.NoError(t, n.SetAnnotations(map[string]string{}))
+	assert.Equal(t, 0, len(getAnnotationsOrDie(t, n)))
+
+	n = NewRNode(nil)
+	if err := n.UnmarshalJSON([]byte(deploymentJSON)); err != nil {
+		t.Fatalf("unexpected unmarshaljson err: %v", err)
+	}
+	annotations := getAnnotationsOrDie(t, n)
+	assert.Equal(t, 2, len(annotations))
+	assert.Equal(t, "51", annotations["area"])
+	assert.Equal(t, "Take me to your leader.", annotations["greeting"])
+	assert.NoError(t, n.SetAnnotations(map[string]string{
+		"annotation1": "foo",
+		"annotation2": "bar",
+	}))
+	annotations = getAnnotationsOrDie(t, n)
+	assert.Equal(t, 2, len(annotations))
+	assert.Equal(t, "foo", annotations["annotation1"])
+	assert.Equal(t, "bar", annotations["annotation2"])
+	assert.NoError(t, n.SetAnnotations(map[string]string{}))
+	assert.Equal(t, 0, len(getAnnotationsOrDie(t, n)))
+}