Add an example of reusable builtin plugins with custom config.

pkg/target/customconfigofbuiltinplugin_test.go

@@ -100,3 +100,118 @@ metadata:
   name: zzz-myService
 `)
 }
+
+// Demo custom configuration as a base.
+func TestReusableCustomNamePrefixer(t *testing.T) {
+	tc := plugins_test.NewEnvForTest(t).Set()
+	defer tc.Reset()
+
+	tc.BuildGoPlugin(
+		"builtin", "", "PrefixSuffixTransformer")
+	tc.BuildGoPlugin(
+		"builtin", "", "LabelTransformer")
+
+	th := kusttest_test.NewKustTestPluginHarness(t, "/app/foo")
+
+	// This kustomization file contains resources that
+	// all happen to be plugin configurations. This makes
+	// these plugins all available as part of a base,
+	// re-usable in any number of other kustomizations.
+	// Just specify the path (or URL) to this base in the
+	// "transformers:" field (not the "resources" field).
+	th.WriteK("/app/mytransformers", `
+resources:
+- prefixer.yaml
+- labeller.yaml
+`)
+	th.WriteF("/app/mytransformers/prefixer.yaml", `
+apiVersion: builtin
+kind: PrefixSuffixTransformer
+metadata:
+  name: myPrefixer
+prefix: zzz-
+fieldSpecs:
+- kind: Deployment
+  path: metadata/name
+- kind: Service
+  path: metadata/name
+`)
+	th.WriteF("/app/mytransformers/labeller.yaml", `
+apiVersion: builtin
+kind: LabelTransformer
+metadata:
+  name: myLabeller
+labels:
+  company: acmeCorp
+fieldSpecs:
+- path: spec/template/metadata/labels
+  kind: Deployment
+`)
+
+	th.WriteK("/app/foo", `
+resources:
+- deployment.yaml
+- role.yaml
+- service.yaml
+transformers:
+- ../mytransformers
+`)
+	th.WriteF("/app/foo/deployment.yaml", `
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: myDeployment
+spec:
+  template:
+    metadata:
+      labels:
+        backend: awesome
+    spec:
+      containers:
+      - name: whatever
+        image: whatever
+`)
+	th.WriteF("/app/foo/role.yaml", `
+apiVersion: v1
+kind: Role
+metadata:
+  name: myRole
+`)
+	th.WriteF("/app/foo/service.yaml", `
+apiVersion: v1
+kind: Service
+metadata:
+  name: myService
+`)
+
+	m, err := th.MakeKustTarget().MakeCustomizedResMap()
+	if err != nil {
+		t.Fatalf("Err: %v", err)
+	}
+	th.AssertActualEqualsExpected(m, `
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: zzz-myDeployment
+spec:
+  template:
+    metadata:
+      labels:
+        backend: awesome
+        company: acmeCorp
+    spec:
+      containers:
+      - image: whatever
+        name: whatever
+---
+apiVersion: v1
+kind: Role
+metadata:
+  name: myRole
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: zzz-myService
+`)
+}