add leveldb store

1. switch to viper for filer store configuration
2. simplify FindEntry() return values, removing “found”
3. add leveldb store

weed/filer2/leveldb/leveldb_store.go

@@ -0,0 +1,171 @@
+package leveldb
+
+import (
+	"fmt"
+	"bytes"
+
+	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/chrislusf/seaweedfs/weed/filer2"
+	leveldb_util "github.com/syndtr/goleveldb/leveldb/util"
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/spf13/viper"
+	weed_util "github.com/chrislusf/seaweedfs/weed/util"
+)
+
+const (
+	DIR_FILE_SEPARATOR = byte(0x00)
+)
+
+func init() {
+	filer2.Stores = append(filer2.Stores, &LevelDBStore{})
+}
+
+type LevelDBStore struct {
+	db *leveldb.DB
+}
+
+func (filer *LevelDBStore) GetName() string {
+	return "leveldb"
+}
+
+func (filer *LevelDBStore) Initialize(viper *viper.Viper) (err error) {
+	dir := viper.GetString("dir")
+	return filer.initialize(dir)
+}
+
+func (filer *LevelDBStore) initialize(dir string) (err error) {
+	if err := weed_util.TestFolderWritable(dir); err != nil {
+		return fmt.Errorf("Check Level Folder %s Writable: %s", dir, err)
+	}
+
+	if filer.db, err = leveldb.OpenFile(dir, nil); err != nil {
+		return
+	}
+	return
+}
+
+func (store *LevelDBStore) InsertEntry(entry *filer2.Entry) (err error) {
+	key := genKey(entry.DirAndName())
+
+	value, err := entry.EncodeAttributesAndChunks()
+	if err != nil {
+		return fmt.Errorf("encoding %s %+v: %v", entry.FullPath, entry.Attr, err)
+	}
+
+	err = store.db.Put(key, value, nil)
+
+	if err != nil {
+		return fmt.Errorf("persisting %s : %v", entry.FullPath, err)
+	}
+
+	// println("saved", entry.FullPath, "chunks", len(entry.Chunks))
+
+	return nil
+}
+
+func (store *LevelDBStore) UpdateEntry(entry *filer2.Entry) (err error) {
+
+	return store.InsertEntry(entry)
+}
+
+func (store *LevelDBStore) FindEntry(fullpath filer2.FullPath) (entry *filer2.Entry, err error) {
+	key := genKey(fullpath.DirAndName())
+
+	data, err := store.db.Get(key, nil)
+
+	if err == leveldb.ErrNotFound {
+		return nil, filer2.ErrNotFound
+	}
+	if err != nil {
+		return nil, fmt.Errorf("get %s : %v", entry.FullPath, err)
+	}
+
+	entry = &filer2.Entry{
+		FullPath: fullpath,
+	}
+	err = entry.DecodeAttributesAndChunks(data)
+	if err != nil {
+		return entry, fmt.Errorf("decode %s : %v", entry.FullPath, err)
+	}
+
+	// println("read", entry.FullPath, "chunks", len(entry.Chunks), "data", len(data), string(data))
+
+	return entry, nil
+}
+
+func (store *LevelDBStore) DeleteEntry(fullpath filer2.FullPath) (entry *filer2.Entry, err error) {
+	key := genKey(fullpath.DirAndName())
+
+	entry, _ = store.FindEntry(fullpath)
+
+	err = store.db.Delete(key, nil)
+	if err != nil {
+		return entry, fmt.Errorf("delete %s : %v", entry.FullPath, err)
+	}
+
+	return entry, nil
+}
+
+func (store *LevelDBStore) ListDirectoryEntries(fullpath filer2.FullPath, startFileName string, inclusive bool,
+	limit int) (entries []*filer2.Entry, err error) {
+
+	directoryPrefix := genDirectoryKeyPrefix(fullpath, "")
+
+	iter := store.db.NewIterator(&leveldb_util.Range{Start: genDirectoryKeyPrefix(fullpath, startFileName)}, nil)
+	for iter.Next() {
+		key := iter.Key()
+		if !bytes.HasPrefix(key, directoryPrefix) {
+			break
+		}
+		fileName := getNameFromKey(key)
+		if fileName == "" {
+			continue
+		}
+		if fileName == startFileName && !inclusive {
+			continue
+		}
+		limit--
+		if limit < 0 {
+			break
+		}
+		entry := &filer2.Entry{
+			FullPath: filer2.NewFullPath(string(fullpath), fileName),
+		}
+		if decodeErr := entry.DecodeAttributesAndChunks(iter.Value()); decodeErr != nil {
+			err = decodeErr
+			glog.V(0).Infof("list %s : %v", entry.FullPath, err)
+			break
+		}
+		entries = append(entries, entry)
+	}
+	iter.Release()
+
+	return entries, err
+}
+
+func genKey(dirPath, fileName string) (key []byte) {
+	key = []byte(dirPath)
+	key = append(key, DIR_FILE_SEPARATOR)
+	key = append(key, []byte(fileName)...)
+	return key
+}
+
+func genDirectoryKeyPrefix(fullpath filer2.FullPath, startFileName string) (keyPrefix []byte) {
+	keyPrefix = []byte(string(fullpath))
+	keyPrefix = append(keyPrefix, DIR_FILE_SEPARATOR)
+	if len(startFileName) > 0 {
+		keyPrefix = append(keyPrefix, []byte(startFileName)...)
+	}
+	return keyPrefix
+}
+
+func getNameFromKey(key []byte) (string) {
+
+	sepIndex := len(key) - 1
+	for sepIndex >= 0 && key[sepIndex] != DIR_FILE_SEPARATOR {
+		sepIndex--
+	}
+
+	return string(key[sepIndex+1:])
+
+}