4 files changed, 215 insertions, 0 deletions
diff --git a/weed/filesys/meta_cache/cache_config.go b/weed/filesys/meta_cache/cache_config.go
new file mode 100644
index 000000000..e6593ebde
--- /dev/null
+++ b/weed/filesys/meta_cache/cache_config.go
@@ -0,0 +1,32 @@
+package meta_cache
+
+import "github.com/chrislusf/seaweedfs/weed/util"
+
+var (
+	_ = util.Configuration(&cacheConfig{})
+)
+
+// implementing util.Configuraion
+type cacheConfig struct {
+	dir string
+}
+
+func (c cacheConfig) GetString(key string) string {
+	return c.dir
+}
+
+func (c cacheConfig) GetBool(key string) bool {
+	panic("implement me")
+}
+
+func (c cacheConfig) GetInt(key string) int {
+	panic("implement me")
+}
+
+func (c cacheConfig) GetStringSlice(key string) []string {
+	panic("implement me")
+}
+
+func (c cacheConfig) SetDefault(key string, value interface{}) {
+	panic("implement me")
+}
diff --git a/weed/filesys/meta_cache/meta_cache.go b/weed/filesys/meta_cache/meta_cache.go
new file mode 100644
index 000000000..4c9090d42
--- /dev/null
+++ b/weed/filesys/meta_cache/meta_cache.go
@@ -0,0 +1,93 @@
+package meta_cache
+
+import (
+	"context"
+	"os"
+	"sync"
+
+	"github.com/chrislusf/seaweedfs/weed/filer2"
+	"github.com/chrislusf/seaweedfs/weed/filer2/leveldb"
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/util"
+)
+
+type MetaCache struct {
+	actualStore filer2.FilerStore
+	sync.RWMutex
+}
+
+func NewMetaCache(dbFolder string) *MetaCache {
+	return &MetaCache{
+		actualStore: openMetaStore(dbFolder),
+	}
+}
+
+func openMetaStore(dbFolder string) filer2.FilerStore {
+
+	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 store
+
+}
+
+func (mc *MetaCache) InsertEntry(ctx context.Context, entry *filer2.Entry) error {
+	mc.Lock()
+	defer mc.Unlock()
+	return mc.actualStore.InsertEntry(ctx, entry)
+}
+
+func (mc *MetaCache) AtomicUpdateEntry(ctx context.Context, oldPath util.FullPath, newEntry *filer2.Entry) error {
+	mc.Lock()
+	defer mc.Unlock()
+	if oldPath != "" {
+		if err := mc.actualStore.DeleteEntry(ctx, oldPath); err != nil {
+			return err
+		}
+	}
+	if newEntry != nil {
+		if err := mc.actualStore.InsertEntry(ctx, newEntry); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (mc *MetaCache) UpdateEntry(ctx context.Context, entry *filer2.Entry) error {
+	mc.Lock()
+	defer mc.Unlock()
+	return mc.actualStore.UpdateEntry(ctx, entry)
+}
+
+func (mc *MetaCache) FindEntry(ctx context.Context, fp util.FullPath) (entry *filer2.Entry, err error) {
+	mc.RLock()
+	defer mc.RUnlock()
+	return mc.actualStore.FindEntry(ctx, fp)
+}
+
+func (mc *MetaCache) DeleteEntry(ctx context.Context, fp util.FullPath) (err error) {
+	mc.Lock()
+	defer mc.Unlock()
+	return mc.actualStore.DeleteEntry(ctx, fp)
+}
+
+func (mc *MetaCache) ListDirectoryEntries(ctx context.Context, dirPath util.FullPath, startFileName string, includeStartFile bool, limit int) ([]*filer2.Entry, error) {
+	mc.RLock()
+	defer mc.RUnlock()
+	return mc.actualStore.ListDirectoryEntries(ctx, dirPath, startFileName, includeStartFile, limit)
+}
+
+func (mc *MetaCache) Shutdown() {
+	mc.Lock()
+	defer mc.Unlock()
+	mc.actualStore.Shutdown()
+}
diff --git a/weed/filesys/meta_cache/meta_cache_init.go b/weed/filesys/meta_cache/meta_cache_init.go
new file mode 100644
index 000000000..58bf6862e
--- /dev/null
+++ b/weed/filesys/meta_cache/meta_cache_init.go
@@ -0,0 +1,21 @@
+package meta_cache
+
+import (
+	"context"
+
+	"github.com/chrislusf/seaweedfs/weed/filer2"
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+	"github.com/chrislusf/seaweedfs/weed/util"
+)
+
+func InitMetaCache(mc *MetaCache, client filer_pb.FilerClient, path string) error {
+	glog.V(0).Infof("synchronizing meta data ...")
+	filer_pb.TraverseBfs(client, util.FullPath(path), func(parentPath util.FullPath, pbEntry *filer_pb.Entry) {
+		entry := filer2.FromPbEntry(string(parentPath), pbEntry)
+		if err := mc.InsertEntry(context.Background(), entry); err != nil {
+			glog.V(0).Infof("read %s: %v", entry.FullPath, err)
+		}
+	})
+	return nil
+}
diff --git a/weed/filesys/meta_cache/meta_cache_subscribe.go b/weed/filesys/meta_cache/meta_cache_subscribe.go
new file mode 100644
index 000000000..2e411a48a
--- /dev/null
+++ b/weed/filesys/meta_cache/meta_cache_subscribe.go
@@ -0,0 +1,69 @@
+package meta_cache
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"time"
+
+	"github.com/chrislusf/seaweedfs/weed/filer2"
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+	"github.com/chrislusf/seaweedfs/weed/util"
+)
+
+func SubscribeMetaEvents(mc *MetaCache, client filer_pb.FilerClient, dir string, lastTsNs int64) error {
+
+	processEventFn := func(resp *filer_pb.SubscribeMetadataResponse) error {
+		message := resp.EventNotification
+		var oldPath util.FullPath
+		var newEntry *filer2.Entry
+		if message.OldEntry != nil {
+			oldPath = util.NewFullPath(resp.Directory, message.OldEntry.Name)
+			glog.V(4).Infof("deleting %v", oldPath)
+		}
+
+		if message.NewEntry != nil {
+			dir := resp.Directory
+			if message.NewParentPath != "" {
+				dir = message.NewParentPath
+			}
+			key := util.NewFullPath(dir, message.NewEntry.Name)
+			glog.V(4).Infof("creating %v", key)
+			newEntry = filer2.FromPbEntry(dir, message.NewEntry)
+		}
+		return mc.AtomicUpdateEntry(context.Background(), oldPath, newEntry)
+	}
+
+	for {
+		err := client.WithFilerClient(func(client filer_pb.SeaweedFilerClient) error {
+			stream, err := client.SubscribeMetadata(context.Background(), &filer_pb.SubscribeMetadataRequest{
+				ClientName: "mount",
+				PathPrefix: dir,
+				SinceNs:    lastTsNs,
+			})
+			if err != nil {
+				return fmt.Errorf("subscribe: %v", err)
+			}
+
+			for {
+				resp, listenErr := stream.Recv()
+				if listenErr == io.EOF {
+					return nil
+				}
+				if listenErr != nil {
+					return listenErr
+				}
+
+				if err := processEventFn(resp); err != nil {
+					return fmt.Errorf("process %v: %v", resp, err)
+				}
+				lastTsNs = resp.TsNs
+			}
+		})
+		if err != nil {
+			glog.V(0).Infof("subscribing filer meta change: %v", err)
+			time.Sleep(time.Second)
+		}
+	}
+}