listen for metadata updates

weed/mount/meta_cache/meta_cache.go

@@ -0,0 +1,160 @@
+package meta_cache
+
+import (
+	"context"
+	"github.com/chrislusf/seaweedfs/weed/filer"
+	"github.com/chrislusf/seaweedfs/weed/filer/leveldb"
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+	"github.com/chrislusf/seaweedfs/weed/util"
+	"os"
+)
+
+// need to have logic similar to FilerStoreWrapper
+// e.g. fill fileId field for chunks
+
+type MetaCache struct {
+	localStore filer.VirtualFilerStore
+	// sync.RWMutex
+	uidGidMapper   *UidGidMapper
+	markCachedFn   func(fullpath util.FullPath)
+	isCachedFn     func(fullpath util.FullPath) bool
+	invalidateFunc func(fullpath util.FullPath, entry *filer_pb.Entry)
+}
+
+func NewMetaCache(dbFolder string, uidGidMapper *UidGidMapper, markCachedFn func(path util.FullPath), isCachedFn func(path util.FullPath) bool, invalidateFunc func(util.FullPath, *filer_pb.Entry)) *MetaCache {
+	return &MetaCache{
+		localStore:   openMetaStore(dbFolder),
+		markCachedFn: markCachedFn,
+		isCachedFn:   isCachedFn,
+		uidGidMapper: uidGidMapper,
+		invalidateFunc: func(fullpath util.FullPath, entry *filer_pb.Entry) {
+			invalidateFunc(fullpath, entry)
+		},
+	}
+}
+
+func openMetaStore(dbFolder string) filer.VirtualFilerStore {
+
+	os.RemoveAll(dbFolder)
+	os.MkdirAll(dbFolder, 0755)
+
+	store := &leveldb.LevelDBStore{}
+	config := &cacheConfig{
+		dir: dbFolder,
+	}
+
+	if err := store.Initialize(config, ""); err != nil {
+		glog.Fatalf("Failed to initialize metadata cache store for %s: %+v", store.GetName(), err)
+	}
+
+	return filer.NewFilerStoreWrapper(store)
+
+}
+
+func (mc *MetaCache) InsertEntry(ctx context.Context, entry *filer.Entry) error {
+	//mc.Lock()
+	//defer mc.Unlock()
+	return mc.doInsertEntry(ctx, entry)
+}
+
+func (mc *MetaCache) doInsertEntry(ctx context.Context, entry *filer.Entry) error {
+	return mc.localStore.InsertEntry(ctx, entry)
+}
+
+func (mc *MetaCache) AtomicUpdateEntryFromFiler(ctx context.Context, oldPath util.FullPath, newEntry *filer.Entry) error {
+	//mc.Lock()
+	//defer mc.Unlock()
+
+	oldDir, _ := oldPath.DirAndName()
+	if mc.isCachedFn(util.FullPath(oldDir)) {
+		if oldPath != "" {
+			if newEntry != nil && oldPath == newEntry.FullPath {
+				// skip the unnecessary deletion
+				// leave the update to the following InsertEntry operation
+			} else {
+				glog.V(3).Infof("DeleteEntry %s", oldPath)
+				if err := mc.localStore.DeleteEntry(ctx, oldPath); err != nil {
+					return err
+				}
+			}
+		}
+	} else {
+		// println("unknown old directory:", oldDir)
+	}
+
+	if newEntry != nil {
+		newDir, _ := newEntry.DirAndName()
+		if mc.isCachedFn(util.FullPath(newDir)) {
+			glog.V(3).Infof("InsertEntry %s/%s", newDir, newEntry.Name())
+			if err := mc.localStore.InsertEntry(ctx, newEntry); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func (mc *MetaCache) UpdateEntry(ctx context.Context, entry *filer.Entry) error {
+	//mc.Lock()
+	//defer mc.Unlock()
+	return mc.localStore.UpdateEntry(ctx, entry)
+}
+
+func (mc *MetaCache) FindEntry(ctx context.Context, fp util.FullPath) (entry *filer.Entry, err error) {
+	//mc.RLock()
+	//defer mc.RUnlock()
+	entry, err = mc.localStore.FindEntry(ctx, fp)
+	if err != nil {
+		return nil, err
+	}
+	mc.mapIdFromFilerToLocal(entry)
+	return
+}
+
+func (mc *MetaCache) DeleteEntry(ctx context.Context, fp util.FullPath) (err error) {
+	//mc.Lock()
+	//defer mc.Unlock()
+	return mc.localStore.DeleteEntry(ctx, fp)
+}
+func (mc *MetaCache) DeleteFolderChildren(ctx context.Context, fp util.FullPath) (err error) {
+	//mc.Lock()
+	//defer mc.Unlock()
+	return mc.localStore.DeleteFolderChildren(ctx, fp)
+}
+
+func (mc *MetaCache) ListDirectoryEntries(ctx context.Context, dirPath util.FullPath, startFileName string, includeStartFile bool, limit int64, eachEntryFunc filer.ListEachEntryFunc) error {
+	//mc.RLock()
+	//defer mc.RUnlock()
+
+	if !mc.isCachedFn(dirPath) {
+		// if this request comes after renaming, it should be fine
+		glog.Warningf("unsynchronized dir: %v", dirPath)
+	}
+
+	_, err := mc.localStore.ListDirectoryEntries(ctx, dirPath, startFileName, includeStartFile, limit, func(entry *filer.Entry) bool {
+		mc.mapIdFromFilerToLocal(entry)
+		return eachEntryFunc(entry)
+	})
+	if err != nil {
+		return err
+	}
+	return err
+}
+
+func (mc *MetaCache) Shutdown() {
+	//mc.Lock()
+	//defer mc.Unlock()
+	mc.localStore.Shutdown()
+}
+
+func (mc *MetaCache) mapIdFromFilerToLocal(entry *filer.Entry) {
+	entry.Attr.Uid, entry.Attr.Gid = mc.uidGidMapper.FilerToLocal(entry.Attr.Uid, entry.Attr.Gid)
+}
+
+func (mc *MetaCache) Debug() {
+	if debuggable, ok := mc.localStore.(filer.Debuggable); ok {
+		println("start debugging")
+		debuggable.Debug(os.Stderr)
+	}
+}