Method bootstrap

value.go:951–984

bootstrap will initialize the log file with key id and baseIV. The below figure shows the layout of log file. +----------------+------------------+------------------+ | keyID(8 bytes) | baseIV(12 bytes)| entry... | +----------------+------------------+------------------+

()

// | keyID(8 bytes) |  baseIV(12 bytes)|	 entry...     |
// +----------------+------------------+------------------+
func (lf *logFile) bootstrap() error {
	var err error
	// delete all the data. because bootstrap is been called while creating vlog and as well
	// as replaying log. While replaying log, there may be any data left. So we need to truncate
	// everything.
	if err = lf.fd.Truncate(0); err != nil {
		return y.Wrapf(err, "Error while bootstraping.")
	}

	if _, err = lf.fd.Seek(0, io.SeekStart); err != nil {
		return y.Wrapf(err, "Error while SeekStart for the logfile %d in logFile.bootstarp", lf.fid)
	}
	// generate data key for the log file.
	var dk *pb.DataKey
	if dk, err = lf.registry.latestDataKey(); err != nil {
		return y.Wrapf(err, "Error while retrieving datakey in logFile.bootstarp")
	}
	lf.dataKey = dk
	// We'll always preserve vlogHeaderSize for key id and baseIV.
	buf := make([]byte, vlogHeaderSize)
	// write key id to the buf.
	// key id will be zero if the logfile is in plain text.
	binary.BigEndian.PutUint64(buf[:8], lf.keyID())
	// generate base IV. It'll be used with offset of the vptr to encrypt the entry.
	if _, err := cryptorand.Read(buf[8:]); err != nil {
		return y.Wrapf(err, "Error while creating base IV, while creating logfile")
	}
	// Initialize base IV.
	lf.baseIV = buf[8:]
	y.AssertTrue(len(lf.baseIV) == 12)
	// write the key id and base IV to the file.
	_, err = lf.fd.Write(buf)
	return err
}

func (vlog *valueLog) createVlogFile(fid uint32) (*logFile, error) {
	path := vlog.fpath(fid)