kyaml: initial support for yaml and resource manipulation

kyaml/yaml/walk/visitor.go

@@ -0,0 +1,38 @@
+// Copyright 2019 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package walk
+
+import (
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+type ListKind int32
+
+const (
+	AssociativeList ListKind = 1 + iota
+	NonAssociateList
+)
+
+// Visitor is invoked by walk with source and destination node pairs
+type Visitor interface {
+	VisitMap(nodes Sources) (*yaml.RNode, error)
+
+	VisitScalar(nodes Sources) (*yaml.RNode, error)
+
+	VisitList(nodes Sources, kind ListKind) (*yaml.RNode, error)
+}
+
+// NoOp is returned if GrepFilter should do nothing after calling Set
+var ClearNode *yaml.RNode = nil