layer1: share watcher namespace manager bootstrap

pkg/utils/namespace_manager.go

@@ -88,6 +88,18 @@ func NewBootstrappedNamespaceManager(resolver *NamespaceResolver, source Namespa
 	return manager
 }
 
+func NewWatcherNamespaceManager(ctx context.Context, namespaces []string, source NamespaceSource, observedAt time.Time, subscribers ...NamespaceSubscriber) (NamespaceManager, error) {
+	manager := NewNamespaceManager()
+	for _, subscriber := range subscribers {
+		if subscriber == nil {
+			continue
+		}
+		manager.Subscribe(subscriber)
+	}
+	_, err := manager.BootstrapAndDispatch(ctx, namespaces, source, observedAt)
+	return manager, err
+}
+
 func (m *inMemoryNamespaceManager) Subscribe(subscriber NamespaceSubscriber) {
 	m.mu.Lock()
 	defer m.mu.Unlock()

pkg/utils/namespace_manager_test.go

@@ -270,6 +270,21 @@ func TestNewBootstrappedNamespaceManager(t *testing.T) {
 	}
 }
 
+func TestNewWatcherNamespaceManager(t *testing.T) {
+	router := &testNamespaceSubscriber{name: "router"}
+	builder := &testNamespaceSubscriber{name: "buildermgr"}
+	manager, err := NewWatcherNamespaceManager(context.Background(), []string{"tenant-b", "tenant-a"}, NamespaceSourceEnv, time.Now().UTC(), router, builder)
+	if err != nil {
+		t.Fatalf("expected watcher manager bootstrap success: %v", err)
+	}
+	if !reflect.DeepEqual([]string{"tenant-a", "tenant-b"}, manager.Snapshot()) {
+		t.Fatalf("expected watcher manager snapshot to match bootstrapped namespaces")
+	}
+	if router.addCalls != 2 || builder.addCalls != 2 {
+		t.Fatalf("expected all subscribers to receive bootstrap dispatch calls")
+	}
+}
+
 func TestNamespaceManagerDispatchAdd(t *testing.T) {
 	manager := NewNamespaceManager()
 	manager.Upsert(NamespaceEvent{Type: NamespaceEventAdd, Name: "tenant-a", Source: NamespaceSourceWatcher})