// NotifyAllLearners sends the current vote to all learners.
func (this *Paxos) NotifyAllLearners() (status error) {
if !this.IsConfigured() || !this.IsAcceptor() {
return nil
}
defer func() {
if status != nil && !errs.IsClosed(status) {
now := time.Now()
next := now.Add(this.opts.LearnRetryInterval)
_ = this.alarm.ScheduleAt(this.uid, next, this.NotifyAllLearners)
}
}()
rlock := this.ctlr.ReadLock("acceptor", "config")
// Stop notifications when all learners know the consensus value.
if len(this.doneLearnerSet) == len(this.learnerList) {
rlock.Unlock()
return nil
}
// Make a copy of what we need: learners and the vote map.
numLearners := len(this.learnerList)
learnerList := append([]string{}, this.learnerList...)
votedValueMap := make(map[int64][]byte)
for ballot, value := range this.votedValueMap {
if ackMap := this.learnerAckMap[ballot]; len(ackMap) < numLearners {
votedValueMap[ballot] = value
}
}
rlock.Unlock()
request := thispb.LearnRequest{}
for ballot, value := range votedValueMap {
request.VotedBallotList = append(request.VotedBallotList, ballot)
request.VotedValueList = append(request.VotedValueList, value)
}
message := thispb.PaxosMessage{}
message.LearnRequest = &request
// Send notification to all learners.
reqHeader := this.msn.NewRequest(this.namespace, this.uid,
"ClassicPaxos.Learn", this.opts.LearnTimeout)
defer this.msn.CloseMessage(reqHeader)
count, errSend := msg.SendAllProto(this.msn, learnerList, reqHeader,
&message)
if errSend != nil {
this.Errorf("could not send learn request to all learners: %v", errSend)
return errSend
}
// Wait for responses from all learners.
for ii := 0; ii < count; ii++ {
message := thispb.PaxosMessage{}
resHeader, errRecv := msg.ReceiveProto(this.msn, reqHeader, &message)
if errRecv != nil {
this.Warningf("could not receive learner responses: %v", errRecv)
break
}
learner := resHeader.GetMessengerId()
if message.LearnResponse == nil {
continue
}
response := message.GetLearnResponse()
// Save the learner acknowledgment to the wal.
change := thispb.AcceptorChange{}
change.AckedLearner = proto.String(learner)
if response.GetKnowsChosenValue() {
change.AckedChosenValue = proto.Bool(true)
} else {
for ballot := range votedValueMap {
change.AckedBallotList = append(change.AckedBallotList, ballot)
}
}
if err := this.UpdateAcceptor(&change); err != nil {
this.Errorf("could not update acceptor state: %v", err)
return err
}
}
return nil
}
