WIP: Expose generic mechanism for configuring the controller builder

pkg/reconciler/reconciler.go

@@ -40,6 +40,7 @@ import (
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/client-go/tools/record"
 	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/builder"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/controller"
 	"sigs.k8s.io/controller-runtime/pkg/handler"
@@ -78,6 +79,7 @@ type Reconciler struct {
 	maxConcurrentReconciles int
 	reconcilePeriod         time.Duration
 	maxHistory              int
+	builderSetupFuncs       []BuilderSetupFunc
 
 	annotSetupOnce       sync.Once
 	annotations          map[string]struct{}
@@ -86,6 +88,9 @@ type Reconciler struct {
 	uninstallAnnotations map[string]annotation.Uninstall
 }
 
+// BuilderSetupFunc allows configuring a controller's builder.
+type BuilderSetupFunc func(b *builder.Builder)
+
 // New creates a new Reconciler that reconciles custom resources that define a
 // Helm release. New takes variadic Option arguments that are used to configure
 // the Reconciler.
@@ -133,7 +138,38 @@ func (r *Reconciler) SetupWithManager(mgr ctrl.Manager) error {
 	r.addDefaults(mgr, controllerName)
 	r.setupScheme(mgr)
 
-	c, err := controller.New(controllerName, mgr, controller.Options{Reconciler: r, MaxConcurrentReconciles: r.maxConcurrentReconciles})
+	// Unfortunately the controller builder API requires us to use the For() method for registering
+	// an object to watch. This object is registered using the standard EnqueueRequestForObject event handler,
+	// without any way to configure this.
+	//
+	// For our object watches we would like to use the sdkhandler.InstrumentedEnqueueRequestForObject event
+	// handler -- the registration is being done in setupWatches.
+	//
+	// Currently I don't see an easy way out here: In order to implement a generic mechanism for configuring
+	// the controller builder we need to use the controller builder API for creating the controller.
+	//
+	// As long as using For() is mandatory we need to provide some object to this method.
+	//
+	// As I understand it, we cannot use the actual type we would like to register for watching, because
+	// it is hard-coded to use an undesired event handler.
+	//
+	// Therefore I am registering a dummy type here. :-(
+	//
+	// -MC
+	dummyObj := &unstructured.Unstructured{}
+	dummyObj.SetGroupVersionKind(schema.GroupVersionKind{
+		Group:   "dummy",
+		Version: "0.0",
+		Kind:    "_dummy",
+	})
+	opts := controller.Options{Reconciler: r, MaxConcurrentReconciles: r.maxConcurrentReconciles}
+	builder := builder.ControllerManagedBy(mgr).Named(controllerName).WithOptions(opts).For(dummyObj)
+
+	for _, f := range r.builderSetupFuncs {
+		f(builder)
+	}
+
+	c, err := builder.Build(r)
 	if err != nil {
 		return err
 	}
@@ -425,6 +461,14 @@ func WithSelector(s metav1.LabelSelector) Option {
 	}
 }
 
+// WithBuilderSetupFunc is an Option that allows configuring a controller's builder using a custom function.
+func WithBuilderSetupFunc(f BuilderSetupFunc) Option {
+	return func(r *Reconciler) error {
+		r.builderSetupFuncs = append(r.builderSetupFuncs, f)
+		return nil
+	}
+}
+
 // Reconcile reconciles a CR that defines a Helm v3 release.
 //
 //   - If a release does not exist for this CR, a new release is installed.

pkg/reconciler/reconciler_test.go

@@ -41,6 +41,7 @@ import (
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/client-go/tools/record"
+	"sigs.k8s.io/controller-runtime/pkg/builder"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/client/fake"
 	"sigs.k8s.io/controller-runtime/pkg/log/zap"
@@ -1222,6 +1223,42 @@ var _ = Describe("Reconciler", func() {
 		})
 	})
 
+	var _ = Describe("Test custom controller builder setup", func() {
+		const customName = "renamed-controller"
+
+		var (
+			mgr             manager.Manager
+			r               *Reconciler
+			err             error
+			builderModified bool
+		)
+		setupBuilder := func(b *builder.Builder) {
+			b.Named(customName)
+			builderModified = true
+		}
+
+		It("Registering builder setup function for reconciler works", func() {
+			mgr = getManagerOrFail()
+			r, err = New(
+				WithGroupVersionKind(gvk),
+				WithChart(chrt),
+				WithInstallAnnotations(annotation.InstallDescription{}),
+				WithUpgradeAnnotations(annotation.UpgradeDescription{}),
+				WithUninstallAnnotations(annotation.UninstallDescription{}),
+				WithOverrideValues(map[string]string{
+					"image.repository": "custom-nginx",
+				}),
+				WithBuilderSetupFunc(setupBuilder),
+			)
+			Expect(err).To(BeNil())
+		})
+
+		It("Setting up reconciler with manager causes custom builder setup to be executed", func() {
+			Expect(r.SetupWithManager(mgr)).To(Succeed())
+			Expect(builderModified).To(BeTrue())
+		})
+	})
+
 	var _ = Describe("Test predicate selector", func() {
 		It("verifying when a valid selector is passed", func() {
 			selectorPass := metav1.LabelSelector{