fix: Cleanup tags when component is removed (#28)

When we receive a deletion request for the resource, we will also try to
clean the TagBindings associated, which helps clean up unused
tagValues/tagkeys residing on the GCP project

Tested locally the following scenarios:
----------------------------------------
Multiple Resources created with multiple tags and deleting the resources
only deletes the unused tags leaving behind the used tags(Since it is
binding to other resources)

Tested change in tag key-values which creates the new ones and deletes
the old ones if unused.

Creation and deletion of tags for single resources.

---------

Co-authored-by: jijinp <[email protected]>

hack/verify-git-clean.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -euo pipefail
-
+go mod tidy
 if [ -n "$(git status --porcelain)" ]; then
-  echo "Working directory is not clean. Please run make generate helm, stash your changes or remove untracked files."
+  echo "Working directory is not clean. Please run make generate helm or run go mod tidy, stash your changes or remove untracked files."
   exit 1
 fi

internal/controller/taggable_controller.go

@@ -98,6 +98,23 @@ func (r *TaggableResourceReconciler[T, P, PT]) Reconcile(ctx context.Context, re
 			if err := r.Update(ctx, resource); err != nil {
 				return ctrl.Result{}, err
 			}
+			log.Info("resource deletion request received trying to delete associated tagValue/tagKey if unused")
+			projectID := r.determineProjectID(ctx, resource)
+			labels := resource.GetLabels()
+			for k, v := range r.LabelMatcher(labels) {
+				// return tagValue.Name, tagKey.Name, nil
+				valueID, keyID, err := r.getValueAndKeyID(ctx, projectID, k, v)
+				if err != nil {
+					return ctrl.Result{Requeue: true, RequeueAfter: 10 * time.Second}, err
+				}
+				if err := r.TagsManager.DeleteValueIfUnused(ctx, projectID, keyID, valueID); err != nil {
+					return ctrl.Result{Requeue: true, RequeueAfter: 10 * time.Second}, err
+				}
+				if err := r.TagsManager.DeleteKeyIfUnused(ctx, projectID, keyID); err != nil {
+					return ctrl.Result{Requeue: true, RequeueAfter: 10 * time.Second}, err
+				}
+			}
+
 		}
 		// Stop reconciliation as the resource is being deleted
 		return ctrl.Result{}, nil
@@ -320,11 +337,30 @@ func (r *TaggableResourceReconciler[T, P, PT]) handleTagBindingsDeletion(ctx con
 				return fmt.Errorf("error deleting tag binding %s: %w", tagBinding.Name, err)
 			}
 		}
+		// Cleanup finalizer
+		controllerutil.RemoveFinalizer(&tagBinding, "cnrm.cloud.google.com/finalizer")
+		if err := r.Update(ctx, &tagBinding); err != nil {
+			return fmt.Errorf("error removing finalizer from resource %s: %w", tagBinding.Name, err)
+		}
 	}
 
 	return nil
 }
 
+func (r *TaggableResourceReconciler[T, P, PT]) getValueAndKeyID(ctx context.Context, projectID, key, value string) (string, string, error) {
+	tagValue, err := r.TagsManager.LookupValue(ctx, projectID, key, value)
+	if err != nil {
+		return "", "", fmt.Errorf("failed to lookup tag value: %w", err)
+	}
+
+	tagKey, err := r.TagsManager.LookupKey(ctx, projectID, key)
+	if err != nil {
+		return "", "", fmt.Errorf("failed to lookup tag key: %w", err)
+	}
+
+	return tagValue.Name, tagKey.Name, nil
+}
+
 func CreateTaggableResourceController[T any, P ResourceMetadataProvider[T], PT ResourcePointer[T]](mgr ctrl.Manager, tagsManager gcp.TagsManager, provider P, labelMatcher func(map[string]string) map[string]string) {
 	if err := (&TaggableResourceReconciler[T, P, PT]{
 		Client:           mgr.GetClient(),

internal/gcp/tags.go

@@ -39,6 +39,8 @@ type TagsManager interface {
 	LookupValue(ctx context.Context, projectID string, key string, value string) (*resourcemanagerpb.TagValue, error)
 	CreateValue(ctx context.Context, projectID string, key string, value string) (*resourcemanagerpb.TagValue, error)
 	GetProjectInfo(ctx context.Context, projectID string) (*resourcemanagerpb.Project, error)
+	DeleteValueIfUnused(ctx context.Context, projectID string, key string, value string) error
+	DeleteKeyIfUnused(ctx context.Context, projectID string, key string) error
 }
 
 type tagsManager struct {
@@ -178,3 +180,51 @@ func (m *tagsManager) GetProjectInfo(ctx context.Context, projectID string) (*re
 	m.cache.Set(cacheKey, project, tagCacheDuration)
 	return project, nil
 }
+
+func (m *tagsManager) DeleteValueIfUnused(ctx context.Context, projectID string, key string, value string) error {
+
+	req := &resourcemanagerpb.DeleteTagValueRequest{
+		Name: value,
+	}
+
+	op, err := m.valuesClient.DeleteTagValue(ctx, req)
+	if err != nil {
+		var ae *apierror.APIError
+		if errors.As(err, &ae) && (ae.GRPCStatus().Code() == codes.FailedPrecondition || ae.GRPCStatus().Code() == codes.NotFound) {
+			// tag value is in use
+			return nil
+		}
+		return fmt.Errorf("failed to call tagValue deletion request: %w", err)
+	}
+
+	_, err = op.Wait(ctx)
+	if err != nil {
+		return fmt.Errorf("failed to delete the tagValue %w", err)
+	}
+
+	m.cache.Delete(cacheKeyTagValue(key, value))
+	return nil
+}
+
+func (m *tagsManager) DeleteKeyIfUnused(ctx context.Context, projectID string, key string) error {
+
+	// Attempt to delete the tag key
+	req := &resourcemanagerpb.DeleteTagKeyRequest{
+		Name: key,
+	}
+	op, err := m.keysClient.DeleteTagKey(ctx, req)
+	if err != nil {
+		var ae *apierror.APIError
+		if errors.As(err, &ae) && (ae.GRPCStatus().Code() == codes.FailedPrecondition || ae.GRPCStatus().Code() == codes.NotFound) {
+			return nil
+		}
+		return fmt.Errorf("failed to call tagKey deletion request: %w", err)
+	}
+
+	_, err = op.Wait(ctx)
+	if err != nil {
+		return fmt.Errorf("failed to delete the tagKey %w", err)
+	}
+	m.cache.Delete(cacheKeyTagKey(key))
+	return nil
+}