improvements jan2025 (#6)

* feat(controller): add lazy watcher, improve resource usage and add pattern validation

- [x] Add cache sync health check for readiness probe verification
- [x] Create namespace lister with API reader support for fresh label queries
- [x] Add pattern validation with warning logs for invalid glob patterns
- [x] Implement lazy watcher initialization mode to scan for active resources
- [x] Add requeue delay to namespace reconciler for cache settlement
- [x] Replace custom containsString with slices.Contains from stdlib
- [x] Add structured logging context to reconcilers (kind, group, version)
- [x] Improve error variable naming for clarity in nested conditions
- [x] Add nil-safe label access in namespace reconciler setup
- [x] Add APIReader to namespace and source reconcilers for fresh data
- [x] Improve type assertions with proper error handling in mirror operations
- [x] Reorder struct fields for consistency and readability
- [x] Add comprehensive pattern validation tests and validation API

* feat(controller): add lazy watcher, improve resource usage and add pattern validation

- [x] Add circuit breaker for reconciliation failure tracking and prevention
- [x] Implement granular registration state tracking (not-registered, source-only, fully-registered)
- [x] Add lazy controller initialization for active resource types only
- [x] Consolidate namespace listing into single API call for efficiency
- [x] Add mirror creation verification to catch webhook rejections
- [x] Implement high-cardinality resource detection and warnings
- [x] Add source deletion check in mirror reconciler to prevent races
- [x] Preserve transformation annotations on errors in mirror reconciliation
- [x] Expand constants documentation with labels vs annotations design rationale
- [x] Add comprehensive test coverage for circuit breaker and registration states
- [x] Add mutation-safety tests for hash computation

* fixup! feat(controller): add lazy watcher, improve resource usage and add pattern validation

pkg/controller/mirror_reconciler.go

@@ -24,7 +24,13 @@ type MirrorReconciler struct {
 
 // Reconcile checks if a mirrored resource's source still exists, and deletes the mirror if orphaned.
 func (r *MirrorReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
-	logger := log.FromContext(ctx)
+	logger := log.FromContext(ctx).WithValues(
+		"mirrorNamespace", req.Namespace,
+		"mirrorName", req.Name,
+		"kind", r.GVK.Kind,
+		"group", r.GVK.Group,
+		"version", r.GVK.Version,
+	)
 
 	// Fetch the mirror resource
 	mirror := &unstructured.Unstructured{}
@@ -73,9 +79,10 @@ func (r *MirrorReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctr
 				"sourceName", sourceName,
 				"sourceUID", sourceUID)
 
-			if err := r.Delete(ctx, mirror); err != nil {
-				logger.Error(err, "failed to delete orphaned mirror")
-				return ctrl.Result{}, err
+			deleteErr := r.Delete(ctx, mirror)
+			if deleteErr != nil {
+				logger.Error(deleteErr, "failed to delete orphaned mirror")
+				return ctrl.Result{}, deleteErr
 			}
 
 			logger.Info("orphaned mirror deleted successfully",
@@ -91,6 +98,16 @@ func (r *MirrorReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctr
 		return ctrl.Result{}, err
 	}
 
+	// Check if source is being deleted - if so, let the SourceReconciler handle cleanup
+	// This prevents race conditions where both reconcilers try to delete mirrors
+	if !source.GetDeletionTimestamp().IsZero() {
+		logger.V(1).Info("source is being deleted, skipping mirror check (SourceReconciler will handle cleanup)",
+			"mirror", req.NamespacedName,
+			"sourceNamespace", sourceNs,
+			"sourceName", sourceName)
+		return ctrl.Result{}, nil
+	}
+
 	// Source exists - verify UID matches
 	actualUID := string(source.GetUID())
 	if actualUID != sourceUID {