Decouple reconcilers from each other

cmd/manager/main.go

@@ -289,6 +289,7 @@ func startControllers(mgr ctrl.Manager, certsReady chan struct{}) {
 	// certs are all in place.
 	setupLog.Info("Waiting for certificate generation to complete")
 	<-certsReady
+	setupLog.Info("Certs ready")
 
 	if testLog {
 		stats.StartLoggingActivity()
@@ -298,18 +299,12 @@ func startControllers(mgr ctrl.Manager, certsReady chan struct{}) {
 	// other components.
 	f := forest.NewForest()
 
-	// Create all validating and mutating admission controllers.
-	if !noWebhooks {
-		setupLog.Info("Registering validating webhook (won't work when running locally; use --no-webhooks)")
-		setup.CreateWebhooks(mgr, f)
-	}
-
-	// Create all reconciling controllers
-	setupLog.Info("Creating controllers", "maxReconciles", maxReconciles)
-	if err := setup.CreateReconcilers(mgr, f, maxReconciles, webhooksOnly, false); err != nil {
-		setupLog.Error(err, "cannot create controllers")
-		os.Exit(1)
+	opts := setup.Options{
+		NoWebhooks:    noWebhooks,
+		MaxReconciles: maxReconciles,
+		ReadOnly:      webhooksOnly,
 	}
+	setup.Create(setupLog, mgr, f, opts)
 
 	setupLog.Info("All controllers started; setup complete")
 }

internal/anchor/reconciler.go

@@ -47,10 +47,10 @@ type Reconciler struct {
 
 	Forest *forest.Forest
 
-	// Affected is a channel of event.GenericEvent (see "Watching Channels" in
+	// affected is a channel of event.GenericEvent (see "Watching Channels" in
 	// https://book-v1.book.kubebuilder.io/beyond_basics/controller_watches.html) that is used to
 	// enqueue additional objects that need updating.
-	Affected chan event.GenericEvent
+	affected chan event.GenericEvent
 
 	// ReadOnly disables writebacks
 	ReadOnly bool
@@ -319,16 +319,22 @@ func (r *Reconciler) updateState(log logr.Logger, inst *api.SubnamespaceAnchor,
 	}
 }
 
-// Enqueue enqueues a subnamespace anchor for later reconciliation. This occurs in a goroutine
-// so the caller doesn't block; since the reconciler is never garbage-collected, this is safe.
-func (r *Reconciler) Enqueue(log logr.Logger, nm, pnm, reason string) {
+// OnChangeNamespace enqueues a subnamespace anchor for later reconciliation. This occurs in a
+// goroutine so the caller doesn't block; since the reconciler is never garbage-collected, this is
+// safe.
+func (r *Reconciler) OnChangeNamespace(log logr.Logger, ns *forest.Namespace) {
+	if ns == nil || !ns.IsSub {
+		return
+	}
+	nm := ns.Name()
+	pnm := ns.Parent().Name()
 	go func() {
 		// The watch handler doesn't care about anything except the metadata.
 		inst := &api.SubnamespaceAnchor{}
 		inst.ObjectMeta.Name = nm
 		inst.ObjectMeta.Namespace = pnm
-		log.V(1).Info("Enqueuing for reconciliation", "affected", pnm+"/"+nm, "reason", reason)
-		r.Affected <- event.GenericEvent{Object: inst}
+		log.V(1).Info("Enqueuing for reconciliation", "affected", pnm+"/"+nm)
+		r.affected <- event.GenericEvent{Object: inst}
 	}()
 }
 
@@ -423,6 +429,8 @@ func (r *Reconciler) deleteNamespace(ctx context.Context, log logr.Logger, inst
 }
 
 func (r *Reconciler) SetupWithManager(mgr ctrl.Manager) error {
+	r.affected = make(chan event.GenericEvent)
+
 	// Maps an subnamespace to its anchor in the parent namespace.
 	nsMapFn := func(obj client.Object) []reconcile.Request {
 		if obj.GetAnnotations()[api.SubnamespaceOf] == "" {
@@ -437,7 +445,7 @@ func (r *Reconciler) SetupWithManager(mgr ctrl.Manager) error {
 	}
 	return ctrl.NewControllerManagedBy(mgr).
 		For(&api.SubnamespaceAnchor{}).
-		Watches(&source.Channel{Source: r.Affected}, &handler.EnqueueRequestForObject{}).
+		Watches(&source.Channel{Source: r.affected}, &handler.EnqueueRequestForObject{}).
 		Watches(&source.Kind{Type: &corev1.Namespace{}}, handler.EnqueueRequestsFromMapFunc(nsMapFn)).
 		Complete(r)
 }

internal/forest/forest.go

@@ -30,16 +30,16 @@ type Forest struct {
 	// We can also move the lock out of the forest and pass it to all reconcilers that need the lock.
 	// In that way, we don't need to put the list in the forest.
 	types []TypeSyncer
+
+	// nsListeners is a list of listeners
+	listeners []NamespaceListener
 }
 
 type namedNamespaces map[string]*Namespace
 
 // TypeSyncer syncs objects of a specific type. Reconcilers implement the interface so that they can be
 // called by the HierarchyReconciler if the hierarchy changes.
 type TypeSyncer interface {
-	// SyncNamespace syncs objects of a namespace for a specific type.
-	SyncNamespace(context.Context, logr.Logger, string) error
-
 	// Provides the GVK that is handled by the reconciler who implements the interface.
 	GetGVK() schema.GroupVersionKind
 
@@ -55,6 +55,12 @@ type TypeSyncer interface {
 	GetNumPropagatedObjects() int
 }
 
+// NamespaceListener has methods that get called whenever a namespace changes.
+type NamespaceListener interface {
+	// OnChangeNamespace is called whenever a namespace changes.
+	OnChangeNamespace(logr.Logger, *Namespace)
+}
+
 func NewForest() *Forest {
 	return &Forest{
 		namespaces: namedNamespaces{},
@@ -148,3 +154,13 @@ func (f *Forest) GetTypeSyncers() []TypeSyncer {
 	copy(types, f.types)
 	return types
 }
+
+func (f *Forest) AddListener(l NamespaceListener) {
+	f.listeners = append(f.listeners, l)
+}
+
+func (f *Forest) OnChangeNamespace(log logr.Logger, ns *Namespace) {
+	for _, l := range f.listeners {
+		l.OnChangeNamespace(log, ns)
+	}
+}

internal/forest/namespace.go

@@ -71,6 +71,9 @@ func (ns *Namespace) Name() string {
 
 // Parent returns a pointer to the parent namespace.
 func (ns *Namespace) Parent() *Namespace {
+	if ns == nil {
+		return nil
+	}
 	return ns.parent
 }
 

internal/forest/namespaceobjects.go

@@ -3,6 +3,7 @@ package forest
 import (
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/types"
 )
 
 // SetSourceObject updates or creates the source object in forest.namespace.
@@ -35,11 +36,11 @@ func (ns *Namespace) DeleteSourceObject(gvk schema.GroupVersionKind, nm string)
 	}
 }
 
-// GetSourceObjects returns all source objects in the namespace.
-func (ns *Namespace) GetSourceObjects(gvk schema.GroupVersionKind) []*unstructured.Unstructured {
-	o := []*unstructured.Unstructured{}
+// GetSourceNames returns all source objects in the namespace.
+func (ns *Namespace) GetSourceNames(gvk schema.GroupVersionKind) []types.NamespacedName {
+	o := []types.NamespacedName{}
 	for _, obj := range ns.sourceObjects[gvk] {
-		o = append(o, obj)
+		o = append(o, types.NamespacedName{Name: obj.GetName(), Namespace: obj.GetNamespace()})
 	}
 	return o
 }
@@ -50,10 +51,10 @@ func (ns *Namespace) GetNumSourceObjects(gvk schema.GroupVersionKind) int {
 	return len(ns.sourceObjects[gvk])
 }
 
-// GetAncestorSourceObjects returns all source objects with the specified name
+// GetAncestorSourceNames returns all source objects with the specified name
 // in the ancestors (including itself) from top down. If the name is not
 // specified, all the source objects in the ancestors will be returned.
-func (ns *Namespace) GetAncestorSourceObjects(gvk schema.GroupVersionKind, name string) []*unstructured.Unstructured {
+func (ns *Namespace) GetAncestorSourceNames(gvk schema.GroupVersionKind, name string) []types.NamespacedName {
 	// The namespace could be nil when we use this function on "ns.Parent()" to
 	// get the source objects of the ancestors excluding itself without caring if
 	// the "ns.Parent()" is nil.
@@ -62,22 +63,22 @@ func (ns *Namespace) GetAncestorSourceObjects(gvk schema.GroupVersionKind, name
 	}
 
 	// Get the source objects in the ancestors from top down.
-	objs := []*unstructured.Unstructured{}
-	ans := ns.AncestryNames()
-	for _, n := range ans {
-		nsObjs := ns.forest.Get(n).GetSourceObjects(gvk)
+	allNNMs := []types.NamespacedName{}
+	ancs := ns.AncestryNames()
+	for _, anc := range ancs {
+		nnms := ns.forest.Get(anc).GetSourceNames(gvk)
 		if name == "" {
 			// Get all the source objects if the name is not specified.
-			objs = append(objs, ns.forest.Get(n).GetSourceObjects(gvk)...)
+			allNNMs = append(allNNMs, nnms...)
 		} else {
 			// If a name is specified, return the matching objects.
-			for _, o := range nsObjs {
-				if o.GetName() == name {
-					objs = append(objs, o)
+			for _, o := range nnms {
+				if o.Name == name {
+					allNNMs = append(allNNMs, o)
 				}
 			}
 		}
 	}
 
-	return objs
+	return allNNMs
 }