func (this *Election) doUpdateConfig(change *thispb.Configuration) error {
walRecord := thispb.WALRecord{}
walRecord.ConfigChange = change
_, errSync := wal.SyncChangeProto(this.wal, this.uid, &walRecord)
if errSync != nil {
this.Errorf("could not append config change wal record: %v", errSync)
return errSync
}
this.doRestoreConfig(change)
return nil
}
func (this *Election) doUpdateElection(change *thispb.ElectionChange) error {
if !this.wal.IsRecovering() {
walRecord := thispb.WALRecord{}
walRecord.ElectionChange = change
_, errQueue := wal.QueueChangeProto(this.wal, this.uid, &walRecord)
if errQueue != nil {
this.Errorf("could not write election change wal record: %v", errQueue)
return errQueue
}
}
atomic.StoreInt64(&this.currentRound, change.GetElectionRound())
this.currentWinner = change.GetElectionWinner()
return nil
}
// TakeCheckpoint logs a checkpoint record to the wal.
func (this *Election) TakeCheckpoint() error {
lock := this.ctlr.ReadLockAll()
defer lock.Unlock()
if this.MajoritySize() <= 0 {
this.Errorf("election instance is not yet configured")
return errs.ErrInvalid
}
checkpoint := thispb.Checkpoint{}
config := thispb.Configuration{}
this.doSaveConfig(&config)
checkpoint.Configuration = &config
if this.InCommittee() {
state := thispb.CommitteeState{}
this.doSaveCommittee(&state)
checkpoint.CommitteeState = &state
}
state := thispb.ElectionState{}
this.doSaveElection(&state)
checkpoint.ElectionState = &state
walRecord := thispb.WALRecord{}
walRecord.Checkpoint = &checkpoint
errAppend := wal.AppendCheckpointProto(this.wal, this.uid, &walRecord)
if errAppend != nil {
this.Errorf("could not append checkpoint record: %v", errAppend)
return errAppend
}
// Checkpoint recent paxos instances' state.
if this.InCommittee() {
state := checkpoint.CommitteeState
for _, round := range state.ElectionRoundList {
if paxos, ok := this.classicPaxosMap[round]; ok {
if err := paxos.TakeCheckpoint(); err != nil {
this.Errorf("could not take checkpoint of paxos instance for "+
"round %d: %v", err)
return err
}
}
}
}
return nil
}
func (this *Election) doUpdateCommittee(change *thispb.CommitteeChange) error {
if !this.wal.IsRecovering() {
walRecord := thispb.WALRecord{}
walRecord.CommitteeChange = change
_, errSync := wal.SyncChangeProto(this.wal, this.uid, &walRecord)
if errSync != nil {
this.Errorf("could not write committee change wal record: %v", errSync)
return errSync
}
}
round := change.GetNewElectionRound()
winner := change.GetNewElectionWinner()
this.electionHistoryMap[round] = winner
return nil
}
// RecoverCheckpoint restores last known election state from a checkpoint
// record.
func (this *Election) RecoverCheckpoint(uid string, data []byte) error {
if uid != this.uid {
// Check if uid belongs to one of our paxos instances.
if this.IsPaxosUID(uid) {
paxos, errGet := this.doGetPaxosInstance(uid)
if errGet != nil {
this.Errorf("could not find paxos instance for %s: %v", uid, errGet)
return errGet
}
return paxos.RecoverCheckpoint(uid, data)
}
this.Errorf("checkpoint record doesn't belong to this instance")
return errs.ErrInvalid
}
walRecord := thispb.WALRecord{}
if err := proto.Unmarshal(data, &walRecord); err != nil {
this.Errorf("could not parse checkpoint wal record: %v", err)
return err
}
if walRecord.Checkpoint == nil {
this.Errorf("checkpoint record has no data")
return errs.ErrCorrupt
}
checkpoint := walRecord.GetCheckpoint()
this.doRestoreConfig(checkpoint.GetConfiguration())
if this.InCommittee() {
if checkpoint.CommitteeState == nil {
this.Errorf("committee member checkpoint has no election state")
return errs.ErrCorrupt
}
this.doRestoreCommittee(checkpoint.GetCommitteeState())
}
this.doRestoreElection(checkpoint.GetElectionState())
return nil
}
// RecoverChange updates election state from a change record.
func (this *Election) RecoverChange(lsn wal.LSN, uid string,
data []byte) error {
if uid != this.uid {
// Check if uid belongs to one of our paxos instances.
if this.IsPaxosUID(uid) {
paxos, errGet := this.doGetPaxosInstance(uid)
if errGet != nil {
this.Errorf("could not find paxos instance for %s: %v", uid, errGet)
return errGet
}
return paxos.RecoverChange(lsn, uid, data)
}
this.Errorf("change record doesn't belong to this instance")
return errs.ErrInvalid
}
walRecord := thispb.WALRecord{}
if err := proto.Unmarshal(data, &walRecord); err != nil {
this.Errorf("could not parse change record: %v", err)
return err
}
switch {
case walRecord.ConfigChange != nil:
this.doRestoreConfig(walRecord.GetConfigChange())
return nil
case walRecord.CommitteeChange != nil:
if !this.InCommittee() {
this.Errorf("found committee change when instance is not a member")
return errs.ErrCorrupt
}
return this.doUpdateCommittee(walRecord.GetCommitteeChange())
case walRecord.ElectionChange != nil:
return this.doUpdateElection(walRecord.GetElectionChange())
default:
this.Errorf("invalid/unknown change record %s", walRecord)
return errs.ErrInvalid
}
return nil
}