Method KeepAlive

datanode/bootstrap/bootstrap_server.go:183–228

KeepAlive is like client/server ping process, to notify health about each other

(stream pb.PeerDataNode_KeepAliveServer)

// KeepAlive is like client/server ping process, to notify health about each other
func (p *PeerDataNodeServerImpl) KeepAlive(stream pb.PeerDataNode_KeepAliveServer) error {
	utils.GetLogger().With("action", "bootstrap").Info("keep alive called")
	var sessionInfo *sessionInfo
	var err error

	defer func() {
		if sessionInfo != nil {
			if err == nil {
				logInfoMsg(sessionInfo, "keep alive stoped")
			} else {
				logErrorMsg(sessionInfo, err, "keep alive failed")
			}
		} else {
			utils.GetLogger().With("action", "bootstrap", "error", err).Error("keep alive stopped")
		}
	}()

	for {
		var session *pb.Session
		session, err = stream.Recv()
		if err == io.EOF {
			err = nil
			break
		}
		if err != nil {
			return err
		}

		if sessionInfo == nil {
			if err = p.validateSessionSource(session.ID, session.NodeID); err != nil {
				return err
			}
			sessionInfo, _ = p.getSession(session.ID)
		}
		// update last live time
		sessionInfo.lastLiveTime = utils.Now()

		if err = stream.Send(&pb.KeepAliveResponse{ID: session.ID, Ttl: sessionInfo.ttl}); err != nil {
			return err
		}
	}
	if sessionInfo != nil {
		p.cleanSession(sessionInfo.sessionID, true)
	}
	return nil
}

// FetchTableShardMetaData to retrieve all metadata for one table/shard
func (p *PeerDataNodeServerImpl) FetchTableShardMetaData(ctx context.Context, req *pb.TableShardMetaDataRequest) (*pb.TableShardMetaData, error) {