add goplugin for exec generators and transformers

pkg/plugins/builtin/executable.go

@@ -0,0 +1,72 @@
+// +build plugin
+
+package main
+
+import (
+	"bytes"
+	"os"
+	"os/exec"
+	"path/filepath"
+
+	"github.com/ghodss/yaml"
+	"sigs.k8s.io/kustomize/pkg/ifc"
+	"sigs.k8s.io/kustomize/pkg/pgmconfig"
+	"sigs.k8s.io/kustomize/pkg/resmap"
+)
+
+type plugin struct {
+	name  string
+	input string
+	rf    *resmap.Factory
+}
+
+var KustomizePlugin plugin
+
+func (p *plugin) Config(
+	ldr ifc.Loader, rf *resmap.Factory, k ifc.Kunstructured) error {
+	dir := filepath.Join(pgmconfig.ConfigRoot(), "plugins")
+	id := k.GetGvk()
+	p.name = filepath.Join(dir, id.Group, id.Version, id.Kind)
+	content, err := yaml.Marshal(k)
+	if err != nil {
+		return err
+	}
+	p.input = string(content)
+	p.rf = rf
+	return nil
+}
+
+func (p *plugin) Generate() (resmap.ResMap, error) {
+	return p.run(nil)
+}
+
+func (p *plugin) Transformer(rm resmap.ResMap) error {
+	result, err := p.run(rm)
+	if err != nil {
+		return err
+	}
+	for id := range rm {
+		delete(rm, id)
+	}
+	for id, r := range result {
+		rm[id] = r
+	}
+	return nil
+}
+
+func (p *plugin) run(rm resmap.ResMap) (resmap.ResMap, error) {
+	cmd := exec.Command(p.name, p.input)
+	cmd.Env = os.Environ()
+	if rm != nil {
+		content, err := rm.EncodeAsYaml()
+		if err != nil {
+			return nil, err
+		}
+		cmd.Stdin = bytes.NewReader(content)
+	}
+	output, err := cmd.Output()
+	if err != nil {
+		return nil, err
+	}
+	return p.rf.NewResMapFromBytes(output)
+}

pkg/plugins/generators.go

@@ -47,14 +47,13 @@ func (l generatorLoader) Load(
 	}
 	var result []transformers.Generator
 	for id, res := range rm {
-		fileName := pluginFileName(l.pc, id)
-		c, err := loadAndConfigurePlugin(fileName, l.ldr, l.rf, res)
+		c, err := loadAndConfigurePlugin(l.pc.DirectoryPath, id, l.ldr, l.rf, res)
 		if err != nil {
 			return nil, err
 		}
 		g, ok := c.(transformers.Generator)
 		if !ok {
-			return nil, fmt.Errorf("plugin %s not a generator", fileName)
+			return nil, fmt.Errorf("plugin %s not a generator", id.String())
 		}
 		result = append(result, g)
 	}

pkg/plugins/transformers.go

@@ -18,8 +18,10 @@ package plugins
 
 import (
 	"fmt"
+	"os"
 	"path/filepath"
 	"plugin"
+	"runtime"
 
 	"github.com/pkg/errors"
 	kplugin "sigs.k8s.io/kustomize/k8sdeps/kv/plugin"
@@ -57,29 +59,53 @@ func (l transformerLoader) Load(
 	}
 	var result []transformers.Transformer
 	for id, res := range rm {
-		fileName := pluginFileName(l.pc, id)
-		c, err := loadAndConfigurePlugin(fileName, l.ldr, l.rf, res)
+		c, err := loadAndConfigurePlugin(l.pc.DirectoryPath, id, l.ldr, l.rf, res)
 		if err != nil {
 			return nil, err
 		}
 		t, ok := c.(transformers.Transformer)
 		if !ok {
-			return nil, fmt.Errorf("plugin %s not a transformer", fileName)
+			return nil, fmt.Errorf("plugin %s not a transformer", id.String())
 		}
 		result = append(result, t)
 	}
 	return result, nil
 }
 
-func pluginFileName(pc *types.PluginConfig, id resid.ResId) string {
+func goPluginFileName(dir string, id resid.ResId) string {
+	return execPluginFileName(dir, id) + ".so"
+}
+
+func execPluginFileName(dir string, id resid.ResId) string {
 	return filepath.Join(
-		pc.DirectoryPath,
-		id.Gvk().Group, id.Gvk().Version, id.Gvk().Kind+".so")
+		dir,
+		id.Gvk().Group, id.Gvk().Version, id.Gvk().Kind)
+}
+
+// isExecAvailable checks if an executable is available
+func isExecAvailable(name string) bool {
+	f, err := os.Stat(name)
+	if os.IsNotExist(err) {
+		return false
+	}
+	if f.Mode()&0111 != 0000 {
+		return true
+	}
+	return false
 }
 
 func loadAndConfigurePlugin(
-	fileName string, ldr ifc.Loader,
+	dir string, id resid.ResId,
+	ldr ifc.Loader,
 	rf *resmap.Factory, res *resource.Resource) (Configurable, error) {
+	var fileName string
+	exec := execPluginFileName(dir, id)
+	if isExecAvailable(exec) {
+		_, f, _, _ := runtime.Caller(1)
+		fileName = filepath.Join(filepath.Dir(f), "builtin", "executable.so")
+	} else {
+		fileName = goPluginFileName(dir, id)
+	}
 	goPlugin, err := plugin.Open(fileName)
 	if err != nil {
 		return nil, errors.Wrapf(err, "plugin %s fails to load", fileName)