add methods to convert resmap to&from rnodes

api/resmap/factory.go

@@ -9,6 +9,7 @@ import (
 	"sigs.k8s.io/kustomize/api/internal/kusterr"
 	"sigs.k8s.io/kustomize/api/resource"
 	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
 )
 
 // Merginator merges resources.
@@ -148,3 +149,20 @@ func newResMapFromResourceSlice(
 	}
 	return result, nil
 }
+
+// NewResMapFromRNodeSlice returns a ResMap from a slice of RNodes
+func (rmF *Factory) NewResMapFromRNodeSlice(rnodes []*yaml.RNode) (ResMap, error) {
+	var resources []*resource.Resource
+	for _, rnode := range rnodes {
+		s, err := rnode.String()
+		if err != nil {
+			return nil, err
+		}
+		r, err := rmF.resF.FromBytes([]byte(s))
+		if err != nil {
+			return nil, err
+		}
+		resources = append(resources, r)
+	}
+	return newResMapFromResourceSlice(resources)
+}

api/resmap/factory_test.go

@@ -17,6 +17,7 @@ import (
 	resmaptest_test "sigs.k8s.io/kustomize/api/testutils/resmaptest"
 	valtest_test "sigs.k8s.io/kustomize/api/testutils/valtest"
 	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
 )
 
 func TestFromFile(t *testing.T) {
@@ -280,3 +281,56 @@ func TestNewResMapFromSecretArgs(t *testing.T) {
 		t.Fatalf("error: %s", err)
 	}
 }
+
+func TestFromRNodeSlice(t *testing.T) {
+	input := `apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRole
+metadata:
+  name: namespace-reader
+rules:
+- apiGroups:
+  - ""
+  resources:
+  - namespaces
+  verbs:
+  - get
+  - watch
+  - list
+  `
+	rnodes := []*yaml.RNode{
+		yaml.MustParse(input),
+	}
+
+	rm, err := rmF.NewResMapFromRNodeSlice(rnodes)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	expected := resmaptest_test.NewRmBuilder(t, rf).Add(
+		map[string]interface{}{
+			"apiVersion": "rbac.authorization.k8s.io/v1",
+			"kind":       "ClusterRole",
+			"metadata": map[string]interface{}{
+				"name": "namespace-reader",
+			},
+			"rules": []interface{}{
+				map[string]interface{}{
+					"apiGroups": []interface{}{
+						"",
+					},
+					"resources": []interface{}{
+						"namespaces",
+					},
+					"verbs": []interface{}{
+						"get",
+						"watch",
+						"list",
+					},
+				},
+			},
+		}).ResMap()
+
+	if err = expected.ErrorIfNotEqualLists(rm); err != nil {
+		t.Fatalf("error: %s", err)
+	}
+}

api/resmap/resmap.go

@@ -10,6 +10,7 @@ import (
 	"sigs.k8s.io/kustomize/api/resid"
 	"sigs.k8s.io/kustomize/api/resource"
 	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
 )
 
 // A Transformer modifies an instance of ResMap.
@@ -235,4 +236,8 @@ type ResMap interface {
 	// Select returns a list of resources that
 	// are selected by a Selector
 	Select(types.Selector) ([]*resource.Resource, error)
+
+	// ToRNodeSlice converts the resources in the resmp
+	// to a list of RNodes
+	ToRNodeSlice() ([]*yaml.RNode, error)
 }

api/resmap/reswrangler.go

@@ -11,6 +11,7 @@ import (
 	"sigs.k8s.io/kustomize/api/resid"
 	"sigs.k8s.io/kustomize/api/resource"
 	"sigs.k8s.io/kustomize/api/types"
+	kyaml_yaml "sigs.k8s.io/kustomize/kyaml/yaml"
 	"sigs.k8s.io/yaml"
 )
 
@@ -561,3 +562,21 @@ func (m *resWrangler) Select(s types.Selector) ([]*resource.Resource, error) {
 	}
 	return result, nil
 }
+
+// ToRNodeSlice converts the resources in the resmp
+// to a list of RNodes
+func (m *resWrangler) ToRNodeSlice() ([]*kyaml_yaml.RNode, error) {
+	var rnodes []*kyaml_yaml.RNode
+	for _, r := range m.Resources() {
+		s, err := r.MarshalJSON()
+		if err != nil {
+			return nil, err
+		}
+		rnode, err := kyaml_yaml.Parse(string(s))
+		if err != nil {
+			return nil, err
+		}
+		rnodes = append(rnodes, rnode)
+	}
+	return rnodes, nil
+}

api/resmap/reswrangler_test.go

@@ -4,6 +4,7 @@
 package resmap_test
 
 import (
+	"bytes"
 	"fmt"
 	"reflect"
 	"strings"
@@ -15,6 +16,7 @@ import (
 	"sigs.k8s.io/kustomize/api/resource"
 	resmaptest_test "sigs.k8s.io/kustomize/api/testutils/resmaptest"
 	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/yaml"
 )
 
 var rf = resource.NewFactory(
@@ -732,3 +734,50 @@ func TestAbsorbAll(t *testing.T) {
 		t.Fatalf("expected error with unspecified behavior")
 	}
 }
+
+func TestToRNodeSlice(t *testing.T) {
+	input := `apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRole
+metadata:
+  name: namespace-reader
+rules:
+- apiGroups:
+  - ""
+  resources:
+  - namespaces
+  verbs:
+  - get
+  - watch
+  - list
+`
+	rm, err := rmF.NewResMapFromBytes([]byte(input))
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	rnodes, err := rm.ToRNodeSlice()
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	b := bytes.NewBufferString("")
+	for i, n := range rnodes {
+		if i != 0 {
+			b.WriteString("---\n")
+		}
+		s, err := n.String()
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		y, err := yaml.JSONToYAML([]byte(s))
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		b.WriteString(string(y))
+	}
+
+	if !reflect.DeepEqual(input, b.String()) {
+		t.Fatalf("actual doesn't match expected.\nActual:\n%s\n===\nExpected:\n%s\n",
+			b.String(), input)
+	}
+}