Switch prefix transformer to kyaml.

api/filters/annotations/annotations.go

@@ -30,7 +30,7 @@ func (f Filter) Filter(nodes []*yaml.RNode) ([]*yaml.RNode, error) {
 			for _, k := range keys {
 				if err := node.PipeE(fsslice.Filter{
 					FsSlice:    f.FsSlice,
-					SetValue:   fsslice.SetEntry(k, f.Annotations[k], yaml.StringTag),
+					SetValue:   filtersutil.SetEntry(k, f.Annotations[k], yaml.StringTag),
 					CreateKind: yaml.MappingNode, // Annotations are MappingNodes.
 					CreateTag:  "!!map",
 				}); err != nil {

api/filters/fieldspec/doc.go

@@ -0,0 +1,6 @@
+// Copyright 2020 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+// Package fieldspec contains a yaml.Filter to modify a resource
+// that matches the FieldSpec.
+package fieldspec

api/filters/fieldspec/example_test.go

@@ -0,0 +1,61 @@
+// Copyright 2020 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package fieldspec_test
+
+import (
+	"bytes"
+	"log"
+	"os"
+
+	. "sigs.k8s.io/kustomize/api/filters/fieldspec"
+	"sigs.k8s.io/kustomize/api/filters/filtersutil"
+	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+func ExampleFilter() {
+	in := &kio.ByteReader{
+		Reader: bytes.NewBufferString(`
+apiVersion: example.com/v1
+kind: Foo
+metadata:
+  name: instance
+---
+apiVersion: example.com/v1
+kind: Bar
+metadata:
+  name: instance
+`),
+	}
+	fltr := Filter{
+		CreateKind: yaml.ScalarNode,
+		SetValue:   filtersutil.SetScalar("green"),
+		FieldSpec:  types.FieldSpec{Path: "a/b", CreateIfNotPresent: true},
+	}
+
+	err := kio.Pipeline{
+		Inputs:  []kio.Reader{in},
+		Filters: []kio.Filter{kio.FilterAll(fltr)},
+		Outputs: []kio.Writer{kio.ByteWriter{Writer: os.Stdout}},
+	}.Execute()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Output:
+	// apiVersion: example.com/v1
+	// kind: Foo
+	// metadata:
+	//   name: instance
+	// a:
+	//   b: green
+	// ---
+	// apiVersion: example.com/v1
+	// kind: Bar
+	// metadata:
+	//   name: instance
+	// a:
+	//   b: green
+}

api/filters/fsslice/fieldspec_filter.go → api/filters/fieldspec/fieldspec.go

@@ -1,24 +1,27 @@
 // Copyright 2019 The Kubernetes Authors.
 // SPDX-License-Identifier: Apache-2.0
 
-package fsslice
+package fieldspec
 
 import (
 	"strings"
 
+	"sigs.k8s.io/kustomize/api/filters/filtersutil"
 	"sigs.k8s.io/kustomize/api/types"
 	"sigs.k8s.io/kustomize/kyaml/errors"
 	"sigs.k8s.io/kustomize/kyaml/yaml"
 )
 
-// fieldSpecFilter applies a single fieldSpec to a single object
-// fieldSpecFilter stores internal state and should not be reused
-type fieldSpecFilter struct {
+var _ yaml.Filter = Filter{}
+
+// Filter applies a single fieldSpec to a single object
+// Filter stores internal state and should not be reused
+type Filter struct {
 	// FieldSpec contains the path to the value to set.
 	FieldSpec types.FieldSpec `yaml:"fieldSpec"`
 
 	// Set the field using this function
-	SetValue SetFn
+	SetValue filtersutil.SetFn
 
 	// CreateKind defines the type of node to create if the field is not found
 	CreateKind yaml.Kind
@@ -29,7 +32,7 @@ type fieldSpecFilter struct {
 	path []string
 }
 
-func (fltr fieldSpecFilter) Filter(obj *yaml.RNode) (*yaml.RNode, error) {
+func (fltr Filter) Filter(obj *yaml.RNode) (*yaml.RNode, error) {
 	// check if the FieldSpec applies to the object
 	if match, err := isMatchGVK(fltr.FieldSpec, obj); !match || err != nil {
 		return obj, errors.Wrap(err)
@@ -43,7 +46,7 @@ func (fltr fieldSpecFilter) Filter(obj *yaml.RNode) (*yaml.RNode, error) {
 	return obj, nil
 }
 
-func (fltr fieldSpecFilter) filter(obj *yaml.RNode) error {
+func (fltr Filter) filter(obj *yaml.RNode) error {
 	if len(fltr.path) == 0 {
 		// found the field -- set its value
 		return fltr.SetValue(obj)
@@ -60,7 +63,7 @@ func (fltr fieldSpecFilter) filter(obj *yaml.RNode) error {
 }
 
 // field calls filter on the field matching the next path element
-func (fltr fieldSpecFilter) field(obj *yaml.RNode) error {
+func (fltr Filter) field(obj *yaml.RNode) error {
 	fieldName, isSeq := isSequenceField(fltr.path[0])
 
 	// lookup the field matching the next path element
@@ -104,9 +107,9 @@ func (fltr fieldSpecFilter) field(obj *yaml.RNode) error {
 }
 
 // seq calls filter on all sequence elements
-func (fltr fieldSpecFilter) seq(obj *yaml.RNode) error {
+func (fltr Filter) seq(obj *yaml.RNode) error {
 	if err := obj.VisitElements(func(node *yaml.RNode) error {
-		// recurse on each element -- re-allocating a fieldSpecFilter is
+		// recurse on each element -- re-allocating a Filter is
 		// not strictly required, but is more consistent with field
 		// and less likely to have side effects
 		// keep the entire path -- it does not contain parts for sequences