use kyaml filters

internal/kubeconfig/contextmodify.go

@@ -15,7 +15,8 @@
 package kubeconfig
 
 import (
-	"github.com/pkg/errors"
+	"errors"
+
 	"sigs.k8s.io/kustomize/kyaml/yaml"
 )
 
@@ -24,60 +25,34 @@ func (k *Kubeconfig) DeleteContextEntry(deleteName string) error {
 	if err != nil {
 		return err
 	}
-
+	if err := contexts.PipeE(
-	i := -1
+		yaml.ElementSetter{
-	for j, ctxNode := range contexts.Content {
+			Keys:   []string{"name"},
-		nameNode := valueOf(ctxNode, "name")
+			Values: []string{deleteName},
-		if nameNode != nil && nameNode.Kind == yaml.ScalarNode && nameNode.Value == deleteName {
+		},
-			i = j
+	); err != nil {
-			break
+		return err
-		}
-	}
-	if i >= 0 {
-		copy(contexts.Content[i:], contexts.Content[i+1:])
-		contexts.Content[len(contexts.Content)-1] = nil
-		contexts.Content = contexts.Content[:len(contexts.Content)-1]
 	}
 	return nil
 }
 
 func (k *Kubeconfig) ModifyCurrentContext(name string) error {
-	currentCtxNode := valueOf(k.rootNode, "current-context")
+	if err := k.config.PipeE(yaml.SetField("current-context", yaml.NewScalarRNode(name))); err != nil {
-	if currentCtxNode != nil {
+		return err
-		currentCtxNode.Value = name
-		return nil
 	}
-
-	// if current-context field doesn't exist, create new field
-	keyNode := &yaml.Node{
-		Kind:  yaml.ScalarNode,
-		Value: "current-context",
-		Tag:   "!!str"}
-	valueNode := &yaml.Node{
-		Kind:  yaml.ScalarNode,
-		Value: name,
-		Tag:   "!!str"}
-	k.rootNode.Content = append(k.rootNode.Content, keyNode, valueNode)
 	return nil
 }
 
 func (k *Kubeconfig) ModifyContextName(old, new string) error {
-	contexts, err := k.contextsNode()
+	context, err := k.config.Pipe(yaml.Lookup("contexts", "[name="+old+"]"))
 	if err != nil {
 		return err
 	}
-
+	if context == nil {
-	var changed bool
+		return errors.New("\"contexts\" entry is nil")
-	for _, contextNode := range contexts.Content {
-		nameNode := valueOf(contextNode, "name")
-		if nameNode.Kind == yaml.ScalarNode && nameNode.Value == old {
-			nameNode.Value = new
-			changed = true
-			break
 	}
-	}
+	if err := context.PipeE(yaml.SetField("name", yaml.NewScalarRNode(new))); err != nil {
-	if !changed {
+		return err
-		return errors.New("no changes were made")
 	}
 	return nil
 }

internal/kubeconfig/contexts.go

@@ -19,48 +19,40 @@ import (
 	"sigs.k8s.io/kustomize/kyaml/yaml"
 )
 
-func (k *Kubeconfig) contextsNode() (*yaml.Node, error) {
+func (k *Kubeconfig) contextsNode() (*yaml.RNode, error) {
-	contexts := valueOf(k.rootNode, "contexts")
+	contexts, err := k.config.Pipe(yaml.Get("contexts"))
+	if err != nil {
+		return nil, err
+	}
 	if contexts == nil {
 		return nil, errors.New("\"contexts\" entry is nil")
-	} else if contexts.Kind != yaml.SequenceNode {
+	} else if contexts.YNode().Kind != yaml.SequenceNode {
 		return nil, errors.New("\"contexts\" is not a sequence node")
 	}
 	return contexts, nil
 }
 
-func (k *Kubeconfig) contextNode(name string) (*yaml.Node, error) {
+func (k *Kubeconfig) contextNode(name string) (*yaml.RNode, error) {
-	contexts, err := k.contextsNode()
+	context, err := k.config.Pipe(yaml.Lookup("contexts", "[name="+name+"]"))
 	if err != nil {
 		return nil, err
 	}
-
+	if context == nil {
-	for _, contextNode := range contexts.Content {
-		nameNode := valueOf(contextNode, "name")
-		if nameNode.Kind == yaml.ScalarNode && nameNode.Value == name {
-			return contextNode, nil
-		}
-	}
 		return nil, errors.Errorf("context with name \"%s\" not found", name)
 	}
+	return context, nil
+}
 
 func (k *Kubeconfig) ContextNames() []string {
-	contexts := valueOf(k.rootNode, "contexts")
+	contexts, err := k.config.Pipe(yaml.Get("contexts"))
-	if contexts == nil {
+	if err != nil {
 		return nil
 	}
-	if contexts.Kind != yaml.SequenceNode {
+	names, err := contexts.ElementValues("name")
+	if err != nil {
 		return nil
 	}
-
+	return names
-	var ctxNames []string
-	for _, ctx := range contexts.Content {
-		nameVal := valueOf(ctx, "name")
-		if nameVal != nil {
-			ctxNames = append(ctxNames, nameVal.Value)
-		}
-	}
-	return ctxNames
 }
 
 func (k *Kubeconfig) ContextExists(name string) bool {
@@ -72,15 +64,3 @@ func (k *Kubeconfig) ContextExists(name string) bool {
 	}
 	return false
 }
-
-func valueOf(mapNode *yaml.Node, key string) *yaml.Node {
-	if mapNode.Kind != yaml.MappingNode {
-		return nil
-	}
-	for i, ch := range mapNode.Content {
-		if i%2 == 0 && ch.Kind == yaml.ScalarNode && ch.Value == key {
-			return mapNode.Content[i+1]
-		}
-	}
-	return nil
-}

internal/kubeconfig/currentcontext.go

@@ -14,18 +14,26 @@
 
 package kubeconfig
 
+import (
+	"strings"
+
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
 // GetCurrentContext returns "current-context" value in given
 // kubeconfig object Node, or returns "" if not found.
 func (k *Kubeconfig) GetCurrentContext() string {
-	v := valueOf(k.rootNode, "current-context")
+	v, err := k.config.Pipe(yaml.Get("current-context"))
-	if v == nil {
+	if err != nil {
 		return ""
 	}
-	return v.Value
+	str, err := v.String()
+	if err != nil {
+		return ""
+	}
+	return strings.TrimSpace(str)
 }
 
 func (k *Kubeconfig) UnsetCurrentContext() error {
-	curCtxValNode := valueOf(k.rootNode, "current-context")
+	return k.config.PipeE(yaml.SetField("current-context", yaml.NewStringRNode("")))
-	curCtxValNode.Value = ""
-	return nil
 }

internal/kubeconfig/kubeconfig.go

@@ -36,7 +36,7 @@ type Kubeconfig struct {
 	loader Loader
 
 	f      ReadWriteResetCloser
-	rootNode *yaml.Node
+	config *yaml.RNode
 }
 
 func (k *Kubeconfig) WithLoader(l Loader) *Kubeconfig {
@@ -65,15 +65,19 @@ func (k *Kubeconfig) Parse() error {
 	if err := yaml.NewDecoder(f).Decode(&v); err != nil {
 		return errors.Wrap(err, "failed to decode")
 	}
-	k.rootNode = v.Content[0]
+	k.config = yaml.NewRNode(&v)
-	if k.rootNode.Kind != yaml.MappingNode {
+	if k.config.YNode().Kind != yaml.MappingNode {
 		return errors.New("kubeconfig file is not a map document")
 	}
 	return nil
 }
 
 func (k *Kubeconfig) Bytes() ([]byte, error) {
-	return yaml.Marshal(k.rootNode)
+	str, err := k.config.String()
+	if err != nil {
+		return nil, err
+	}
+	return []byte(str), nil
 }
 
 func (k *Kubeconfig) Save() error {
@@ -82,5 +86,5 @@ func (k *Kubeconfig) Save() error {
 	}
 	enc := yaml.NewEncoder(k.f)
 	enc.SetIndent(0)
-	return enc.Encode(k.rootNode)
+	return enc.Encode(k.config.YNode())
 }

internal/kubeconfig/namespace.go

@@ -14,7 +14,11 @@
 
 package kubeconfig
 
-import "sigs.k8s.io/kustomize/kyaml/yaml"
+import (
+	"strings"
+
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
 
 const (
 	defaultNamespace = "default"
@@ -25,53 +29,27 @@ func (k *Kubeconfig) NamespaceOfContext(contextName string) (string, error) {
 	if err != nil {
 		return "", err
 	}
-	ctxBody := valueOf(ctx, "context")
+	namespace, err := ctx.Pipe(yaml.Lookup("context", "namespace"))
-	if ctxBody == nil {
+	if namespace == nil || err != nil {
-		return defaultNamespace, nil
+		return defaultNamespace, err
 	}
-	ns := valueOf(ctxBody, "namespace")
+	nsStr, err := namespace.String()
-	if ns == nil || ns.Value == "" {
+	if nsStr == "" || err != nil {
-		return defaultNamespace, nil
+		return defaultNamespace, err
 	}
-	return ns.Value, nil
+	return strings.TrimSpace(nsStr), nil
 }
 
 func (k *Kubeconfig) SetNamespace(ctxName string, ns string) error {
-	ctxNode, err := k.contextNode(ctxName)
+	ctx, err := k.contextNode(ctxName)
 	if err != nil {
 		return err
 	}
-
+	if err := ctx.PipeE(
-	var ctxBodyNodeWasEmpty bool // actual namespace value is in contexts[index].context.namespace, but .context might not exist
+		yaml.LookupCreate(yaml.MappingNode, "context"),
-	ctxBodyNode := valueOf(ctxNode, "context")
+		yaml.SetField("namespace", yaml.NewStringRNode(ns)),
-	if ctxBodyNode == nil {
+	); err != nil {
-		ctxBodyNodeWasEmpty = true
+		return err
-		ctxBodyNode = &yaml.Node{
-			Kind: yaml.MappingNode,
-		}
-	}
-
-	nsNode := valueOf(ctxBodyNode, "namespace")
-	if nsNode != nil {
-		nsNode.Value = ns
-		return nil
-	}
-
-	keyNode := &yaml.Node{
-		Kind:  yaml.ScalarNode,
-		Value: "namespace",
-		Tag:   "!!str"}
-	valueNode := &yaml.Node{
-		Kind:  yaml.ScalarNode,
-		Value: ns,
-		Tag:   "!!str"}
-	ctxBodyNode.Content = append(ctxBodyNode.Content, keyNode, valueNode)
-	if ctxBodyNodeWasEmpty {
-		ctxNode.Content = append(ctxNode.Content, &yaml.Node{
-			Kind:  yaml.ScalarNode,
-			Value: "context",
-			Tag:   "!!str",
-		}, ctxBodyNode)
 	}
 	return nil
 }