Function to set labels.

api/filters/labels/doc.go

@@ -0,0 +1,6 @@
+// Copyright 2020 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+// Package labels contains a kio.Filter implementation of the kustomize
+// labels transformer.
+package labels

api/filters/labels/example_test.go

@@ -0,0 +1,55 @@
+// Copyright 2020 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package labels
+
+import (
+	"bytes"
+	"log"
+	"os"
+
+	"sigs.k8s.io/kustomize/api/internal/plugins/builtinconfig"
+	"sigs.k8s.io/kustomize/kyaml/kio"
+)
+
+func ExampleFilter() {
+	fss := builtinconfig.MakeDefaultConfig().CommonLabels
+	err := kio.Pipeline{
+		Inputs: []kio.Reader{&kio.ByteReader{Reader: bytes.NewBufferString(`
+apiVersion: example.com/v1
+kind: Foo
+metadata:
+  name: instance
+---
+apiVersion: example.com/v1
+kind: Bar
+metadata:
+  name: instance
+`)}},
+		Filters: []kio.Filter{Filter{
+			Labels: map[string]string{
+				"foo": "bar",
+			},
+			FsSlice: fss,
+		}},
+		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
+	//   labels:
+	//     foo: bar
+	// ---
+	// apiVersion: example.com/v1
+	// kind: Bar
+	// metadata:
+	//   name: instance
+	//   labels:
+	//     foo: bar
+}

api/filters/labels/labels.go

@@ -0,0 +1,43 @@
+// Copyright 2020 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package labels
+
+import (
+	"sigs.k8s.io/kustomize/api/filters/filtersutil"
+	"sigs.k8s.io/kustomize/api/filters/fsslice"
+	"sigs.k8s.io/kustomize/api/types"
+	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+type labelMap map[string]string
+
+// Filter sets labels.
+type Filter struct {
+	// Labels is the set of labels to apply to the inputs
+	Labels labelMap `yaml:"labels,omitempty"`
+
+	// FsSlice identifies the label fields.
+	FsSlice types.FsSlice
+}
+
+var _ kio.Filter = Filter{}
+
+func (f Filter) Filter(nodes []*yaml.RNode) ([]*yaml.RNode, error) {
+	keys := filtersutil.SortedMapKeys(f.Labels)
+	_, err := kio.FilterAll(yaml.FilterFunc(
+		func(node *yaml.RNode) (*yaml.RNode, error) {
+			for _, k := range keys {
+				if err := node.PipeE(fsslice.Filter{
+					FsSlice:    f.FsSlice,
+					SetValue:   fsslice.SetEntry(k, f.Labels[k]),
+					CreateKind: yaml.MappingNode, // Labels are MappingNodes.
+				}); err != nil {
+					return nil, err
+				}
+			}
+			return node, nil
+		})).Filter(nodes)
+	return nodes, err
+}

api/filters/labels/labels_test.go

@@ -0,0 +1,139 @@
+// Copyright 2020 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package labels
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"sigs.k8s.io/kustomize/api/internal/plugins/builtinconfig"
+	filtertest_test "sigs.k8s.io/kustomize/api/testutils/filtertest"
+	"sigs.k8s.io/kustomize/api/types"
+)
+
+var labelsFs = builtinconfig.MakeDefaultConfig().CommonLabels
+
+func TestLabels_Filter(t *testing.T) {
+	testCases := map[string]struct {
+		input          string
+		expectedOutput string
+		filter         Filter
+		fsSlice        types.FsSlice
+	}{
+		"add": {
+			input: `
+apiVersion: example.com/v1
+kind: Foo
+metadata:
+  name: instance
+  labels:
+    hero: batman
+    fiend: riddler
+`,
+			expectedOutput: `
+apiVersion: example.com/v1
+kind: Foo
+metadata:
+  name: instance
+  labels:
+    hero: batman
+    fiend: riddler
+    auto: ford
+    bean: cannellini
+    clown: emmett kelley
+    dragon: smaug
+`,
+			filter: Filter{Labels: labelMap{
+				"clown":  "emmett kelley",
+				"auto":   "ford",
+				"dragon": "smaug",
+				"bean":   "cannellini",
+			}},
+		},
+		"update": {
+			input: `
+apiVersion: example.com/v1
+kind: Foo
+metadata:
+  name: instance
+  labels:
+    hero: batman
+    fiend: riddler
+`,
+			expectedOutput: `
+apiVersion: example.com/v1
+kind: Foo
+metadata:
+  name: instance
+  labels:
+    hero: superman
+    fiend: luthor
+    bean: cannellini
+    clown: emmett kelley
+`,
+			filter: Filter{Labels: labelMap{
+				"clown": "emmett kelley",
+				"hero":  "superman",
+				"fiend": "luthor",
+				"bean":  "cannellini",
+			}},
+		},
+		"data-fieldspecs": {
+			input: `
+apiVersion: example.com/v1
+kind: Foo
+metadata:
+  name: instance
+---
+apiVersion: example.com/v1
+kind: Bar
+metadata:
+  name: instance
+`,
+			expectedOutput: `
+apiVersion: example.com/v1
+kind: Foo
+metadata:
+  name: instance
+  labels:
+    sleater: kinney
+a:
+  b:
+    sleater: kinney
+---
+apiVersion: example.com/v1
+kind: Bar
+metadata:
+  name: instance
+  labels:
+    sleater: kinney
+a:
+  b:
+    sleater: kinney
+`,
+			filter: Filter{Labels: labelMap{
+				"sleater": "kinney",
+			}},
+			fsSlice: []types.FieldSpec{
+				{
+					Path:               "a/b",
+					CreateIfNotPresent: true,
+				},
+			},
+		},
+	}
+
+	for tn, tc := range testCases {
+		t.Run(tn, func(t *testing.T) {
+			filter := tc.filter
+			filter.FsSlice = append(labelsFs, tc.fsSlice...)
+			if !assert.Equal(t,
+				strings.TrimSpace(tc.expectedOutput),
+				strings.TrimSpace(filtertest_test.RunFilter(t, tc.input, filter))) {
+				t.FailNow()
+			}
+		})
+	}
+}