[BUG] diskStorage calls ReplaceComponentList function which deletes dir (not recreated again) when contents are empty

[obitoquilt]

What happened:

diskStorage calls ReplaceComponentList function which deletes dir (not recreated again) when contents are empty.

For example, i installed cilium charts (version is 1.15.6). The cilium-agent component has a empty dir named /etc/kubernetes/cache/cilium-agent/cilium2announcementpolicies.v2alpha1.cilium.io. After diskStorage calls ReplaceComponentList function, the empty dir is renamed to /etc/kubernetes/cache/cilium-agent/tmp_cilium2announcementpolicies.v2alpha1.cilium.io.

Because the contents are empty, diskStorage does nothing and removes the tmp dir. So the original dir would not be recreated.

func (ds *diskStorage) ReplaceComponentList(component string, gvr schema.GroupVersionResource, namespace string, contents map[storage.Key][]byte) error {
	rootKey, err := ds.KeyFunc(storage.KeyBuildInfo{
		Component: component,
		Resources: gvr.Resource,
		Group:     gvr.Group,
		Version:   gvr.Version,
		Namespace: namespace,
	})
	if err != nil {
		return err
	}
	storageKey := rootKey.(storageKey)

	for key := range contents {
		if !strings.HasPrefix(key.Key(), rootKey.Key()) {
			return storage.ErrInvalidContent
		}
	}

	if !ds.lockKey(storageKey) {
		return storage.ErrStorageAccessConflict
	}
	defer ds.unLockKey(storageKey)

	// 1. mv old dir into tmp_dir when rootKey dir already exists
	absPath := filepath.Join(ds.baseDir, storageKey.Key())
	tmpRootKey := getTmpKey(storageKey)
	tmpPath := filepath.Join(ds.baseDir, tmpRootKey.Key())
	if !fs.IfExists(absPath) {
		if err := ds.fsOperator.CreateDir(absPath); err != nil {
			return fmt.Errorf("could not create dir at %s", absPath)
		}
		if len(contents) == 0 {
			// nothing need to create, so just return
			return nil
		}
	}
	if ok, err := fs.IsDir(absPath); err == nil && !ok {
		return fmt.Errorf("%s is not a dir", absPath)
	} else if err != nil {
		return fmt.Errorf("could not check the path %s, %v", absPath, err)
	}
	// absPath exists and is a dir
	if err := ds.fsOperator.Rename(absPath, tmpPath); err != nil {
		return err
	}

	// 2. create new file with contents
	// TODO: if error happens, we may need retry mechanism, or add some mechanism to do consistency check.
	for key, data := range contents {
		path := filepath.Join(ds.baseDir, key.Key())
		if err := ds.fsOperator.CreateDir(filepath.Dir(path)); err != nil && err != fs.ErrExists {
			klog.Errorf("could not create dir at %s, %v", filepath.Dir(path), err)
			continue
		}
		if err := ds.fsOperator.CreateFile(path, data); err != nil {
			klog.Errorf("could not write data to %s, %v", path, err)
			continue
		}
		klog.V(4).Infof("[diskStorage] ReplaceComponentList store data at %s", path)
	}

	//  3. delete old tmp dir
	return ds.fsOperator.DeleteDir(tmpPath)

What you expected to happen:

it should be recreate the empty dir

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:

Environment:

• OpenYurt version: v1.5.0
• Kubernetes version (use kubectl version): v1.27.4
• OS (e.g: cat /etc/os-release): centos linux
• Kernel (e.g. uname -a): 5.15.13-1.el7.elrepo.x86_64
• Install tools:
• Others:

others

/kind bug

[rambohe-ch]

@obitoquilt Thank you for raising the issue. I agree with you that there is a bug of Yurthub storage, would you like to make a pull request to fix this bug?

[vie-serendipity]

I make a pull request to fix this bug.