Ease doing custom configuration of builtin plugins.

cmd/pluginator/main.go

@@ -16,6 +16,15 @@ import (
 	"sigs.k8s.io/kustomize/v3/pkg/plugins"
 )
 
+//go:generate stringer -type=pluginType
+type pluginType int
+
+const (
+	unknown pluginType = iota
+	Transformer
+	Generator
+)
+
 func main() {
 	root := inputFileRoot()
 	file, err := os.Open(root + ".go")
@@ -34,24 +43,41 @@ func main() {
 		fmt.Sprintf(
 			"// Code generated by pluginator on %s; DO NOT EDIT.",
 			root))
-	w.write("package builtin")
+	w.write("package " + plugins.BuiltinPluginPackage)
+
+	pType := unknown
 
 	for scanner.Scan() {
 		l := scanner.Text()
 		if strings.HasPrefix(l, "//go:generate") {
 			continue
 		}
-		if l == "var "+plugins.PluginSymbol+" plugin" {
-			w.write("func New" + root + "Plugin() *" + root + "Plugin {")
-			w.write("  return &" + root + "Plugin{}")
-			w.write("}")
+		if strings.HasPrefix(l, "//noinspection") {
 			continue
 		}
+		if l == "var "+plugins.PluginSymbol+" plugin" {
+			continue
+		}
+		if strings.Contains(l, " Transform(") {
+			if pType != unknown {
+				log.Fatal("unexpected Transform(")
+			}
+			pType = Transformer
+		} else if strings.Contains(l, " Generate(") {
+			if pType != unknown {
+				log.Fatal("unexpected Generate(")
+			}
+			pType = Generator
+		}
 		w.write(l)
 	}
 	if err := scanner.Err(); err != nil {
 		log.Fatal(err)
 	}
+	w.write("")
+	w.write("func New" + root + "Plugin() resmap." + pType.String() + "Plugin {")
+	w.write("  return &" + root + "Plugin{}")
+	w.write("}")
 }
 
 func inputFileRoot() string {
@@ -93,7 +119,7 @@ func makeOutputFileName(root string) string {
 		pgmconfig.DomainName,
 		pgmconfig.ProgramName,
 		pgmconfig.PluginRoot,
-		"builtin",
+		plugins.BuiltinPluginPackage,
 		root+".go")
 }
 

cmd/pluginator/plugintype_string.go

@@ -0,0 +1,25 @@
+// Code generated by "stringer -type=pluginType"; DO NOT EDIT.
+
+package main
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[unknown-0]
+	_ = x[Transformer-1]
+	_ = x[Generator-2]
+}
+
+const _pluginType_name = "unknownTransformerGenerator"
+
+var _pluginType_index = [...]uint8{0, 7, 18, 27}
+
+func (i pluginType) String() string {
+	if i < 0 || i >= pluginType(len(_pluginType_index)-1) {
+		return "pluginType(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+	return _pluginType_name[_pluginType_index[i]:_pluginType_index[i+1]]
+}