One plugin per dir.

plugin/someteam.example.com/v1/dateprefixer/DatePrefixer.go

@@ -0,0 +1,38 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+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{}
+
+var KustomizePlugin plugin
+
+func (p *plugin) Config(
+	ldr ifc.Loader, rf *resmap.Factory, c []byte) error {
+	return nil
+}
+
+// Returns a constant, rather than
+//   time.Now().Format("2006-01-02")
+// to make tests happy.
+// This is just an example.
+func getDate() string {
+	return "2018-05-11"
+}
+
+func (p *plugin) Transform(m resmap.ResMap) error {
+	tr, err := transformers.NewNamePrefixSuffixTransformer(
+		getDate()+"-", "",
+		config.MakeDefaultConfig().NamePrefix)
+	if err != nil {
+		return err
+	}
+	return tr.Transform(m)
+}