layer1: add namespace remove dispatch step 33

pkg/utils/namespace_manager.go

@@ -57,6 +57,7 @@ type NamespaceManager interface {
 	SnapshotSubscribers() []string
 	Upsert(event NamespaceEvent) NamespaceRecord
 	DispatchAdd(ctx context.Context, namespace string) (NamespaceRecord, bool, error)
+	DispatchRemove(ctx context.Context, namespace string) (NamespaceRecord, bool, error)
 	DispatchResync(ctx context.Context, namespace string) (NamespaceRecord, bool, error)
 	MarkPartState(namespace string, part string, state NamespacePartState) (NamespaceRecord, bool)
 	MarkPartRegistering(namespace string, part string) (NamespaceRecord, bool)
@@ -250,6 +251,30 @@ func (m *inMemoryNamespaceManager) DispatchAdd(ctx context.Context, namespace st
 	})
 }
 
+func (m *inMemoryNamespaceManager) DispatchRemove(ctx context.Context, namespace string) (NamespaceRecord, bool, error) {
+	record, ok := m.Get(namespace)
+	if !ok {
+		return NamespaceRecord{}, false, nil
+	}
+
+	var firstErr error
+	for _, subscriber := range m.snapshotSubscriberObjects() {
+		err := subscriber.OnNamespaceRemove(ctx, record)
+		if err != nil && firstErr == nil {
+			firstErr = err
+		}
+	}
+
+	removedRecord := m.Upsert(NamespaceEvent{
+		Type:       NamespaceEventRemove,
+		Name:       record.Name,
+		Labels:     record.Labels,
+		Source:     record.Source,
+		ObservedAt: time.Now().UTC(),
+	})
+	return removedRecord, true, firstErr
+}
+
 func (m *inMemoryNamespaceManager) DispatchResync(ctx context.Context, namespace string) (NamespaceRecord, bool, error) {
 	return m.dispatch(ctx, namespace, func(subscriber NamespaceSubscriber, record NamespaceRecord) error {
 		return subscriber.OnNamespaceResync(ctx, record)