One plugin per dir.

pkg/plugins/compiler.go

@@ -21,6 +21,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"strings"
 	"time"
 
 	"sigs.k8s.io/kustomize/k8sdeps/kv/plugin"
@@ -95,7 +96,8 @@ func goBin() string {
 // Compile reads ${srcRoot}/${g}/${v}/${k}.go
 //    and writes ${objRoot}/${g}/${v}/${k}.so
 func (b *Compiler) Compile(g, v, k string) error {
-	objDir := filepath.Join(b.objRoot, g, v)
+	lowK := strings.ToLower(k)
+	objDir := filepath.Join(b.objRoot, g, v, lowK)
 	objFile := filepath.Join(objDir, k) + ".so"
 	if RecentFileExists(objFile) {
 		// Skip rebuilding it.
@@ -105,7 +107,7 @@ func (b *Compiler) Compile(g, v, k string) error {
 	if err != nil {
 		return err
 	}
-	srcFile := filepath.Join(b.srcRoot, g, v, k) + ".go"
+	srcFile := filepath.Join(b.srcRoot, g, v, lowK, k) + ".go"
 	if !FileExists(srcFile) {
 		return fmt.Errorf(
 			"cannot find source %s", srcFile)
@@ -114,7 +116,6 @@ func (b *Compiler) Compile(g, v, k string) error {
 		"build",
 		"-buildmode",
 		"plugin",
-		"-tags=plugin",
 		"-o", objFile, srcFile,
 	}
 	goBin := goBin()

pkg/plugins/compiler_test.go

@@ -42,7 +42,7 @@ func TestCompiler(t *testing.T) {
 
 	expectObj := filepath.Join(
 		c.ObjRoot(),
-		"someteam.example.com", "v1", "DatePrefixer.so")
+		"someteam.example.com", "v1", "dateprefixer", "DatePrefixer.so")
 	if FileExists(expectObj) {
 		t.Errorf("obj file should not exist yet: %s", expectObj)
 	}
@@ -56,7 +56,7 @@ func TestCompiler(t *testing.T) {
 
 	expectObj = filepath.Join(
 		c.ObjRoot(),
-		"builtin", "", "SecretGenerator.so")
+		"builtin", "", "secretgenerator", "SecretGenerator.so")
 	if FileExists(expectObj) {
 		t.Errorf("obj file should not exist yet: %s", expectObj)
 	}

pkg/plugins/execplugin.go

@@ -22,7 +22,6 @@ import (
 	"io/ioutil"
 	"os"
 	"os/exec"
-	"path/filepath"
 	"strings"
 	"syscall"
 
@@ -39,8 +38,8 @@ const (
 // ExecPlugin record the name and args of an executable
 // It triggers the executable generator and transformer
 type ExecPlugin struct {
-	// name of the executable
-	name string
+	// absolute path of the executable
+	path string
 
 	// Optional command line arguments to the executable
 	// pulled from specially named fields in cfg.
@@ -57,15 +56,13 @@ type ExecPlugin struct {
 	ldr ifc.Loader
 }
 
-func NewExecPlugin(root string, id resid.ResId) *ExecPlugin {
-	return &ExecPlugin{
-		name: filepath.Join(root, pluginPath(id)),
-	}
+func NewExecPlugin(p string) *ExecPlugin {
+	return &ExecPlugin{path: p}
 }
 
 // isAvailable checks to see if the plugin is available
 func (p *ExecPlugin) isAvailable() bool {
-	f, err := os.Stat(p.name)
+	f, err := os.Stat(p.path)
 	if os.IsNotExist(err) {
 		return false
 	}
@@ -164,7 +161,7 @@ func (p *ExecPlugin) invokePlugin(input []byte) ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
-	cmd := exec.Command(p.name, args...)
+	cmd := exec.Command(p.path, args...)
 	cmd.Env = p.getEnv()
 	cmd.Stdin = bytes.NewReader(input)
 	cmd.Stderr = os.Stderr
@@ -226,7 +223,7 @@ func (p *ExecPlugin) updateResMapValues(output []byte, rm resmap.ResMap) error {
 		idString, ok := annotations[idAnnotation]
 		if !ok {
 			return fmt.Errorf("the transformer %s should not remove annotation %s",
-				p.name, idAnnotation)
+				p.path, idAnnotation)
 		}
 		id := resid.ResId{}
 		err := yaml.Unmarshal([]byte(idString), &id)

pkg/plugins/execplugin_test.go

@@ -51,8 +51,9 @@ s/$BAR/bar/g
 `))
 
 	p := NewExecPlugin(
-		plugin.DefaultPluginConfig().DirectoryPath,
-		pluginConfig.Id())
+		AbsolutePluginPath(
+			plugin.DefaultPluginConfig(),
+			pluginConfig.Id()))
 
 	yaml, err := pluginConfig.AsYAML()
 	if err != nil {
@@ -60,9 +61,9 @@ s/$BAR/bar/g
 	}
 	p.Config(ldr, rf, yaml)
 
-	expected := "/kustomize/plugin/someteam.example.com/v1/SedTransformer"
-	if !strings.HasSuffix(p.name, expected) {
-		t.Fatalf("expected suffix '%s', got '%s'", expected, p.name)
+	expected := "/kustomize/plugin/someteam.example.com/v1/sedtransformer/SedTransformer"
+	if !strings.HasSuffix(p.path, expected) {
+		t.Fatalf("expected suffix '%s', got '%s'", expected, p.path)
 	}
 
 	expected = `apiVersion: someteam.example.com/v1

pkg/plugins/loader.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"path/filepath"
 	"plugin"
+	"strings"
 
 	"github.com/pkg/errors"
 	"sigs.k8s.io/kustomize/pkg/ifc"
@@ -96,8 +97,20 @@ func (l *Loader) LoadTransformer(
 	return t, nil
 }
 
-func pluginPath(id resid.ResId) string {
-	return filepath.Join(id.Gvk().Group, id.Gvk().Version, id.Gvk().Kind)
+func relativePluginPath(id resid.ResId) string {
+	return filepath.Join(
+		id.Gvk().Group,
+		id.Gvk().Version,
+		strings.ToLower(id.Gvk().Kind))
+}
+
+func AbsolutePluginPath(pc *types.PluginConfig, id resid.ResId) string {
+	return filepath.Join(
+		pc.DirectoryPath, relativePluginPath(id), id.Gvk().Kind)
+}
+
+func (l *Loader) absolutePluginPath(id resid.ResId) string {
+	return AbsolutePluginPath(l.pc, id)
 }
 
 func (l *Loader) loadAndConfigurePlugin(
@@ -106,7 +119,8 @@ func (l *Loader) loadAndConfigurePlugin(
 		return nil, errors.Errorf(
 			"plugins not enabled, but trying to load %s", res.Id())
 	}
-	if p := NewExecPlugin(l.pc.DirectoryPath, res.Id()); p.isAvailable() {
+	if p := NewExecPlugin(
+		l.absolutePluginPath(res.Id())); p.isAvailable() {
 		c = p
 	} else {
 		c, err = l.loadGoPlugin(res.Id())
@@ -135,26 +149,26 @@ func (l *Loader) loadAndConfigurePlugin(
 var registry = make(map[string]Configurable)
 
 func (l *Loader) loadGoPlugin(id resid.ResId) (c Configurable, err error) {
+	regId := relativePluginPath(id)
 	var ok bool
-	path := pluginPath(id)
-	if c, ok = registry[path]; ok {
+	if c, ok = registry[regId]; ok {
 		return c, nil
 	}
-	name := filepath.Join(l.pc.DirectoryPath, path)
-	p, err := plugin.Open(name + ".so")
+	absPath := l.absolutePluginPath(id)
+	p, err := plugin.Open(absPath + ".so")
 	if err != nil {
-		return nil, errors.Wrapf(err, "plugin %s fails to load", name)
+		return nil, errors.Wrapf(err, "plugin %s fails to load", absPath)
 	}
 	symbol, err := p.Lookup(PluginSymbol)
 	if err != nil {
 		return nil, errors.Wrapf(
 			err, "plugin %s doesn't have symbol %s",
-			name, PluginSymbol)
+			regId, PluginSymbol)
 	}
 	c, ok = symbol.(Configurable)
 	if !ok {
-		return nil, fmt.Errorf("plugin %s not configurable", name)
+		return nil, fmt.Errorf("plugin %s not configurable", regId)
 	}
-	registry[path] = c
+	registry[regId] = c
 	return
 }

pkg/plugins/loader_test.go

@@ -43,7 +43,7 @@ port: "12345"
 )
 
 func TestLoader(t *testing.T) {
-	tc := plugin.NewPluginTestEnv(t).Set()
+	tc := plugin.NewEnvForTest(t).Set()
 	defer tc.Reset()
 
 	tc.BuildGoPlugin(