kyaml: initial support for yaml and resource manipulation

kyaml/kio/example_test.go

@@ -0,0 +1,110 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package kio_test
+
+import (
+	"bytes"
+	"log"
+	"os"
+
+	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+func Example() {
+	input := bytes.NewReader([]byte(`apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: nginx
+  labels:
+    app: nginx
+spec:
+  replicas: 3
+  selector:
+    matchLabels:
+      app: nginx
+  template:
+    metadata:
+      labels:
+        app: nginx
+    spec:
+      containers:
+      - name: nginx
+        image: nginx:1.7.9
+        ports:
+        - containerPort: 80
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: nginx
+spec:
+  selector:
+    app: nginx
+  ports:
+    - protocol: TCP
+      port: 80
+      targetPort: 80
+`))
+
+	// setAnnotationFn
+	setAnnotationFn := kio.FilterFunc(func(operand []*yaml.RNode) ([]*yaml.RNode, error) {
+		for i := range operand {
+			resource := operand[i]
+			_, err := resource.Pipe(yaml.SetAnnotation("foo", "bar"))
+			if err != nil {
+				return nil, err
+			}
+		}
+		return operand, nil
+	})
+
+	err := kio.Pipeline{
+		Inputs:  []kio.Reader{&kio.ByteReader{Reader: input}},
+		Filters: []kio.Filter{setAnnotationFn},
+		Outputs: []kio.Writer{kio.ByteWriter{Writer: os.Stdout}},
+	}.Execute()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Output:
+	// apiVersion: apps/v1
+	// kind: Deployment
+	// metadata:
+	//   name: nginx
+	//   labels:
+	//     app: nginx
+	//   annotations:
+	//     foo: bar
+	// spec:
+	//   replicas: 3
+	//   selector:
+	//     matchLabels:
+	//       app: nginx
+	//   template:
+	//     metadata:
+	//       labels:
+	//         app: nginx
+	//     spec:
+	//       containers:
+	//       - name: nginx
+	//         image: nginx:1.7.9
+	//         ports:
+	//         - containerPort: 80
+	// ---
+	// apiVersion: v1
+	// kind: Service
+	// metadata:
+	//   name: nginx
+	//   annotations:
+	//     foo: bar
+	// spec:
+	//   selector:
+	//     app: nginx
+	//   ports:
+	//   - protocol: TCP
+	//     port: 80
+	//     targetPort: 80
+}