some transformer plugins

pkg/target/kusttarget.go

@@ -21,6 +21,9 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
+	"os"
+	"path/filepath"
+	"plugin"
 	"strings"
 
 	"github.com/ghodss/yaml"
@@ -318,5 +321,58 @@ func (kt *KustTarget) newTransformer(
 		return nil, err
 	}
 	r = append(r, t)
+
+	tp, err := kt.loadTransformerPlugins()
+	if err != nil {
+		return nil, err
+	}
+	r = append(r, tp...)
 	return transformers.NewMultiTransformer(r), nil
 }
+
+func (kt *KustTarget) loadTransformerPlugins() ([]transformers.Transformer, error) {
+	var result []transformers.Transformer
+
+	pc := types.PluginConfig{
+		DirectoryPath: os.Getenv("GOPATH"),
+		GoEnabled:     true}
+
+	root := filepath.Join(
+		pc.DirectoryPath, "src", "sigs.k8s.io", "kustomize", "plugins")
+
+	if !pc.GoEnabled {
+		return nil, fmt.Errorf("plugins not enabled")
+	}
+
+	transformerPluginConfigs, err := kt.rFactory.FromFiles(
+		kt.ldr, kt.kustomization.Transformers)
+
+	for id, res := range transformerPluginConfigs {
+		fileName := filepath.Join(root, id.Gvk().Kind+".so")
+		goPlugin, err := plugin.Open(fileName)
+		if err != nil {
+			return nil, fmt.Errorf("plugin %s file not opened", fileName)
+		}
+		symbol, err := goPlugin.Lookup("Transformer")
+		if err != nil {
+			return nil, fmt.Errorf("plugin %s fails lookup", fileName)
+		}
+		c, ok := symbol.(transformers.Configurable)
+		if !ok {
+			return nil, fmt.Errorf("plugin %s not configurable", fileName)
+		}
+		err = c.Config(res)
+		if err != nil {
+			return nil, errors.Wrapf(err, "plugin %s fails configuration", fileName)
+		}
+		t, ok := c.(transformers.Transformer)
+		if !ok {
+			return nil, fmt.Errorf("plugin %s not a transformer", fileName)
+		}
+
+		result = append(result, t)
+		fmt.Printf("Added plugin %s\n", fileName)
+
+	}
+	return result, err
+}

pkg/target/transformerplugin_test.go

@@ -0,0 +1,119 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+ 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 target_test
+
+import (
+	"sigs.k8s.io/kustomize/pkg/types"
+	"testing"
+)
+
+func writeDeployment(th *KustTestHarness, path string) {
+	th.writeF(path, `
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: myDeployment
+spec:
+  template:
+    metadata:
+      labels:
+        backend: awesome
+    spec:
+      containers:
+      - name: whatever
+        image: whatever
+`)
+}
+
+func writeStringPrefixer(th *KustTestHarness, path string) {
+	th.writeF(path, `
+apiVersion: strings.microwoosh.com/v1
+kind: StringPrefixer
+metadata:
+  name: myStringPrefixer
+prefix: apple-
+`)
+}
+
+func writeDatePrefixer(th *KustTestHarness, path string) {
+	th.writeF(path, `
+apiVersion: team.dater.com/v1
+kind: DatePrefixer
+metadata:
+  name: myDatePrefixer
+`)
+}
+
+func TestOrderedTransformers(t *testing.T) {
+	th := NewKustTestHarnessWithPluginConfig(
+		t, "/app", types.PluginConfig{GoEnabled: true})
+	th.writeK("/app", `
+resources:
+- deployment.yaml
+transformers:
+- stringPrefixer.yaml
+`)
+	writeDeployment(th, "/app/deployment.yaml")
+	writeStringPrefixer(th, "/app/stringPrefixer.yaml")
+	writeDatePrefixer(th, "/app/datePrefixer.yaml")
+	m, err := th.makeKustTarget().MakeCustomizedResMap()
+	if err != nil {
+		t.Fatalf("Err: %v", err)
+	}
+	th.assertActualEqualsExpected(m, `
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: apple-myDeployment
+spec:
+  template:
+    metadata:
+      labels:
+        backend: awesome
+    spec:
+      containers:
+      - image: whatever
+        name: whatever
+`)
+}
+
+func xTestTransformedTransformers(t *testing.T) {
+	th := NewKustTestHarnessWithPluginConfig(
+		t, "/app/overlay", types.PluginConfig{GoEnabled: true})
+
+	th.writeK("/app/base", `
+resources:
+- stringPrefixer.yaml
+transformers:
+- datePrefixer.yaml
+`)
+	writeStringPrefixer(th, "/app/base/stringPrefixer.yaml")
+	writeDatePrefixer(th, "/app/base/datePrefixer.yaml")
+
+	th.writeK("/app/overlay", `
+resources:
+- deployment.yaml
+transformers:
+- ../base
+`)
+	writeDeployment(th, "/app/overlay/deployment.yaml")
+
+	m, err := th.makeKustTarget().MakeCustomizedResMap()
+	if err != nil {
+		t.Fatalf("Err: %v", err)
+	}
+	th.assertActualEqualsExpected(m, `
+HEY
+`)
+}

pkg/transformers/transformer.go

@@ -17,10 +17,17 @@ limitations under the License.
 // Package transformers has implementations of resmap.ResMap transformers.
 package transformers
 
-import "sigs.k8s.io/kustomize/pkg/resmap"
+import (
+	"sigs.k8s.io/kustomize/pkg/ifc"
+	"sigs.k8s.io/kustomize/pkg/resmap"
+)
 
 // A Transformer modifies an instance of resmap.ResMap.
 type Transformer interface {
 	// Transform modifies data in the argument, e.g. adding labels to resources that can be labelled.
 	Transform(m resmap.ResMap) error
 }
+
+type Configurable interface {
+	Config(k ifc.Kunstructured) error
+}

plugins/DatePrefixer.go

@@ -0,0 +1,30 @@
+// +build plugin
+
+package main
+
+import (
+	"time"
+
+	"sigs.k8s.io/kustomize/pkg/ifc"
+	"sigs.k8s.io/kustomize/pkg/resmap"
+	"sigs.k8s.io/kustomize/pkg/transformers"
+	"sigs.k8s.io/kustomize/pkg/transformers/config"
+)
+
+type plugin struct{}
+
+var Transformer plugin
+
+func (p *plugin) Config(k ifc.Kunstructured) error {
+	return nil
+}
+
+func (p *plugin) Transform(m resmap.ResMap) error {
+	tr, err := transformers.NewNamePrefixSuffixTransformer(
+		time.Now().Format("2006-01-02")+"-", "",
+		config.MakeDefaultConfig().NamePrefix)
+	if err != nil {
+		return err
+	}
+	return tr.Transform(m)
+}

plugins/StringPrefixer.go

@@ -0,0 +1,44 @@
+// +build plugin
+
+// Assuming GOPATH is something like
+//   ~/gopath
+// and this source file is located at
+//   $GOPATH/src/sigs.k8s.io/kustomize/plugins/StringPrefixer.go,
+// build it like this:
+//   dir=$GOPATH/src/sigs.k8s.io/kustomize/plugins
+//   go build -buildmode plugin -tags=plugin \
+//     -o $dir/StringPrefixer.so $dir/StringPrefixer.go
+
+package main
+
+import (
+	"sigs.k8s.io/kustomize/pkg/ifc"
+	"sigs.k8s.io/kustomize/pkg/resmap"
+	"sigs.k8s.io/kustomize/pkg/transformers"
+	"sigs.k8s.io/kustomize/pkg/transformers/config"
+)
+
+type plugin struct{
+	prefix string
+}
+
+var Transformer plugin
+
+func (p *plugin) Config(k ifc.Kunstructured) error {
+	var err error
+	p.prefix, err = k.GetFieldValue("prefix")
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (p *plugin) Transform(m resmap.ResMap) error {
+	tr, err := transformers.NewNamePrefixSuffixTransformer(
+		p.prefix, "",
+		config.MakeDefaultConfig().NamePrefix)
+	if err != nil {
+		return err
+	}
+	return tr.Transform(m)
+}

plugins/kvMaker.go

@@ -0,0 +1,24 @@
+// +build plugin
+
+package main
+var database = map[string]string{
+  "TREE":      "oak",
+  "ROCKET":    "Saturn V",
+  "FRUIT":     "apple",
+  "VEGETABLE": "carrot",
+  "SIMPSON":   "homer",
+}
+
+type plugin struct{}
+var KVSource plugin
+func (p plugin) Get(
+    root string, args []string) (map[string]string, error) {
+  r := make(map[string]string)
+  for _, k := range args {
+    v, ok := database[k]
+    if ok {
+      r[k] = v
+    }
+  }
+  return r, nil
+}