Util functions for kyaml <-> kunstruct compatibility

api/filters/filtersutil/filtersutil.go

@@ -0,0 +1,77 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package filtersutil
+
+import (
+	"encoding/json"
+
+	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+// ApplyToJSON applies the filter to the json objects.
+func ApplyToJSON(filter kio.Filter, objs ...marshalerUnmarshaler) error {
+	var nodes []*yaml.RNode
+	for i := range objs {
+		node, err := getRNode(objs[i])
+		if err != nil {
+			return err
+		}
+		nodes = append(nodes, node)
+		l, err := filter.Filter([]*yaml.RNode{node})
+		if err != nil {
+			return err
+		}
+		err = setRNode(objs[i], l[0])
+		if err != nil {
+			return err
+		}
+	}
+
+	_, err := filter.Filter(nodes)
+	if err != nil {
+		return err
+	}
+
+	for i := range nodes {
+		err = setRNode(objs[i], nodes[i])
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+type marshalerUnmarshaler interface {
+	json.Unmarshaler
+	json.Marshaler
+}
+
+// getRNode converts k into an RNode
+func getRNode(k json.Marshaler) (*yaml.RNode, error) {
+	j, err := k.MarshalJSON()
+	if err != nil {
+		return nil, err
+	}
+	return yaml.Parse(string(j))
+}
+
+// setRNode marshals node into k
+func setRNode(k json.Unmarshaler, node *yaml.RNode) error {
+	s, err := node.String()
+	if err != nil {
+		return err
+	}
+	m := map[string]interface{}{}
+	if err := yaml.Unmarshal([]byte(s), &m); err != nil {
+		return err
+	}
+
+	b, err := json.Marshal(m)
+	if err != nil {
+		return err
+	}
+	return k.UnmarshalJSON(b)
+}

api/filters/filtersutil/filtersutil_test.go

@@ -0,0 +1,60 @@
+package filtersutil_test
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"sigs.k8s.io/kustomize/api/filters/filtersutil"
+	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+func TestApplyToJSON(t *testing.T) {
+	instance1 := bytes.NewBufferString(`{"kind": "Foo"}`)
+	instance2 := bytes.NewBufferString(`{"kind": "Bar"}`)
+	err := filtersutil.ApplyToJSON(
+		kio.FilterFunc(func(nodes []*yaml.RNode) ([]*yaml.RNode, error) {
+			for i := range nodes {
+				set := yaml.SetField(
+					"foo", yaml.NewScalarRNode("bar"))
+				node := nodes[i]
+				err := node.PipeE(set)
+				if !assert.NoError(t, err) {
+					t.FailNow()
+				}
+			}
+			return nodes, nil
+		}), buffer{Buffer: instance1}, buffer{Buffer: instance2},
+	)
+	if !assert.NoError(t, err) {
+		t.FailNow()
+	}
+
+	if !assert.Equal(t,
+		strings.TrimSpace(`{"foo":"bar","kind":"Foo"}`),
+		strings.TrimSpace(instance1.String())) {
+		t.FailNow()
+	}
+
+	if !assert.Equal(t,
+		strings.TrimSpace(`{"foo":"bar","kind":"Bar"}`),
+		strings.TrimSpace(instance2.String())) {
+		t.FailNow()
+	}
+}
+
+type buffer struct {
+	*bytes.Buffer
+}
+
+func (buff buffer) UnmarshalJSON(b []byte) error {
+	buff.Reset()
+	buff.Write(b)
+	return nil
+}
+
+func (buff buffer) MarshalJSON() ([]byte, error) {
+	return buff.Bytes(), nil
+}