package meta import ( "encoding/binary" "errors" "fmt" "go.etcd.io/bbolt" ) // version contains current metabase version. const version = 2 var versionKey = []byte("version") // ErrOutdatedVersion is returned on initializing // an existing metabase that is not compatible with // the current code version. var ErrOutdatedVersion = errors.New("invalid version") func checkVersion(tx *bbolt.Tx, initialized bool) error { var knownVersion bool b := tx.Bucket(shardInfoBucket) if b != nil { data := b.Get(versionKey) if len(data) == 8 { knownVersion = true stored := binary.LittleEndian.Uint64(data) if stored != version { return fmt.Errorf("%w: expected=%d, stored=%d", ErrOutdatedVersion, version, stored) } } } if !initialized { // new database, write version return updateVersion(tx, version) } else if !knownVersion { // db is initialized but no version // has been found; that could happen // if the db is corrupted or the version // is <2 (is outdated and requires resync // anyway) return ErrOutdatedVersion } return nil } func updateVersion(tx *bbolt.Tx, version uint64) error { data := make([]byte, 8) binary.LittleEndian.PutUint64(data, version) b, err := tx.CreateBucketIfNotExists(shardInfoBucket) if err != nil { return fmt.Errorf("can't create auxiliary bucket: %w", err) } return b.Put(versionKey, data) }