fix: concurrent map writes when replicating namespaced objects (#1264)

Signed-off-by: Dario Tranchitella <dario@tranchitella.eu>

controllers/resources/processor.go

@@ -79,6 +79,7 @@ func (r *Processor) HandlePruning(ctx context.Context, current, desired sets.Set
 	return updateStatus
 }
 
+//nolint:gocognit
 func (r *Processor) HandleSection(ctx context.Context, tnt capsulev1beta2.Tenant, allowCrossNamespaceSelection bool, tenantLabel string, resourceIndex int, spec capsulev1beta2.ResourceSpec) ([]string, error) {
 	log := ctrllog.FromContext(ctx)
 
@@ -125,7 +126,6 @@ func (r *Processor) HandleSection(ctx context.Context, tnt capsulev1beta2.Tenant
 
 	objLabels[Label] = fmt.Sprintf("%d", resourceIndex)
 	objLabels[tenantLabel] = tnt.GetName()
-
 	// processed will contain the sets of resources replicated, both for the raw and the Namespaced ones:
 	// these are required to perform a final pruning once the replication has been occurred.
 	processed := sets.NewString()
@@ -173,17 +173,20 @@ func (r *Processor) HandleSection(ctx context.Context, tnt capsulev1beta2.Tenant
 			var wg sync.WaitGroup
 
 			errorsChan := make(chan error, len(objs.Items))
-
+			// processedRaw is used to avoid concurrent map writes during iteration of namespaced items:
+			// the objects will be then added to processed variable if the resulting string is not empty,
+			// meaning it has been processed correctly.
+			processedRaw := make([]string, len(objs.Items))
 			// Iterating over all the retrieved objects from the resource spec to get replicated in all the selected Namespaces:
 			// in case of error during the create or update function, this will be appended to the list of errors.
-			for _, o := range objs.Items {
+			for i, o := range objs.Items {
 				obj := o
 				obj.SetNamespace(ns.Name)
 				obj.SetOwnerReferences(nil)
 
 				wg.Add(1)
 
-				go func(obj unstructured.Unstructured) {
+				go func(index int, obj unstructured.Unstructured) {
 					defer wg.Done()
 
 					kv := keysAndValues
@@ -204,8 +207,8 @@ func (r *Processor) HandleSection(ctx context.Context, tnt capsulev1beta2.Tenant
 					replicatedItem.Namespace = ns.Name
 					replicatedItem.APIVersion = obj.GetAPIVersion()
 
-					processed.Insert(replicatedItem.String())
-				}(obj)
+					processedRaw[index] = replicatedItem.String()
+				}(i, obj)
 			}
 
 			wg.Wait()
@@ -216,6 +219,14 @@ func (r *Processor) HandleSection(ctx context.Context, tnt capsulev1beta2.Tenant
 					syncErr = errors.Join(syncErr, err)
 				}
 			}
+
+			for _, p := range processedRaw {
+				if p == "" {
+					continue
+				}
+
+				processed.Insert(p)
+			}
 		}
 
 		for rawIndex, item := range spec.RawItems {