// 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 }