// requestLeaderLease sends a request to obtain or extend a leader lease for
// this replica. Unless an error is returned, the obtained lease will be valid
// for a time interval containing the requested timestamp.
func (r *Range) requestLeaderLease(timestamp proto.Timestamp) error {
// TODO(Tobias): get duration from configuration, either as a config flag
// or, later, dynamically adjusted.
duration := int64(DefaultLeaderLeaseDuration)
// Prepare a Raft command to get a leader lease for this replica.
expiration := timestamp.Add(duration, 0)
args := &proto.InternalLeaderLeaseRequest{
RequestHeader: proto.RequestHeader{
Key: r.Desc().StartKey,
Timestamp: timestamp,
CmdID: proto.ClientCmdID{
WallTime: r.rm.Clock().Now().WallTime,
Random: rand.Int63(),
},
},
Lease: proto.Lease{
Start: timestamp,
Expiration: expiration,
RaftNodeID: r.rm.RaftNodeID(),
},
}
// Send lease request directly to raft in order to skip unnecessary
// checks from normal request machinery, (e.g. the command queue).
errChan, pendingCmd := r.proposeRaftCommand(r.context(), args, &proto.InternalLeaderLeaseResponse{})
var err error
if err = <-errChan; err == nil {
// Next if the command was committed, wait for the range to apply it.
err = <-pendingCmd.done
}
return err
}
// requestLeaderLease sends a request to obtain or extend a leader lease for
// this replica. Unless an error is returned, the obtained lease will be valid
// for a time interval containing the requested timestamp.
func (r *Replica) requestLeaderLease(timestamp proto.Timestamp) error {
// TODO(Tobias): get duration from configuration, either as a config flag
// or, later, dynamically adjusted.
duration := int64(DefaultLeaderLeaseDuration)
// Prepare a Raft command to get a leader lease for this replica.
expiration := timestamp.Add(duration, 0)
desc := r.Desc()
args := &proto.LeaderLeaseRequest{
RequestHeader: proto.RequestHeader{
Key: desc.StartKey,
Timestamp: timestamp,
CmdID: proto.ClientCmdID{
WallTime: r.rm.Clock().Now().WallTime,
Random: rand.Int63(),
},
RangeID: desc.RangeID,
},
Lease: proto.Lease{
Start: timestamp,
Expiration: expiration,
RaftNodeID: r.rm.RaftNodeID(),
},
}
// Send lease request directly to raft in order to skip unnecessary
// checks from normal request machinery, (e.g. the command queue).
// Note that the command itself isn't traced, but usually the caller
// waiting for the result has an active Trace.
errChan, pendingCmd := r.proposeRaftCommand(r.context(), args)
if err := <-errChan; err != nil {
return err
}
// Next if the command was committed, wait for the range to apply it.
return (<-pendingCmd.done).Err
}
