Add leveldb to db backend and fix error wrapping

manager/db_leveldb.go

@@ -0,0 +1,51 @@
+package manager
+
+import (
+	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+// implement kv interface backed by leveldb
+type leveldbAdapter struct {
+	db *leveldb.DB
+}
+
+func (b *leveldbAdapter) InitBucket(bucket string) (err error) {
+	// no-op
+	return
+}
+
+func (b *leveldbAdapter) Get(bucket string, key string) (v []byte, err error) {
+	v, err = b.db.Get([]byte(bucket+key), nil)
+	return
+}
+
+func (b *leveldbAdapter) GetAll(bucket string) (m map[string][]byte, err error) {
+	it := b.db.NewIterator(util.BytesPrefix([]byte(bucket)), nil)
+	defer it.Release()
+	m = make(map[string][]byte)
+	for it.Next() {
+		k := string(it.Key())
+		actualKey := k[len(bucket):]
+		// it.Value() changes on next iteration
+		val := it.Value()
+		v := make([]byte, len(val))
+		copy(v, it.Value())
+		m[actualKey] = v
+	}
+	return
+}
+
+func (b *leveldbAdapter) Put(bucket string, key string, value []byte) error {
+	err := b.db.Put([]byte(bucket+key), []byte(value), nil)
+	return err
+}
+
+func (b *leveldbAdapter) Delete(bucket string, key string) error {
+	err := b.db.Delete([]byte(bucket+key), nil)
+	return err
+}
+
+func (b *leveldbAdapter) Close() error {
+	return b.db.Close()
+}