Golang PaxosMessage.Phase1Request方法代碼示例

// doPhase1 performs classic paxos phase1 steps.
func (this *Paxos) doPhase1(ctxHeader *msgpb.Header, ballot int64,
	phase1AcceptorList []string) ([]byte, []string, error) {

	phase1request := thispb.Phase1Request{}
	phase1request.BallotNumber = proto.Int64(ballot)
	message := thispb.PaxosMessage{}
	message.Phase1Request = &phase1request

	reqHeader := msg.NewNestedRequest(this.msn, ctxHeader, this.namespace,
		this.uid, "ClassicPaxos.Phase1")
	defer this.msn.CloseMessage(reqHeader)

	count, errSend := msg.SendAllProto(this.msn, phase1AcceptorList, reqHeader,
		&message)
	if errSend != nil && count < this.MajoritySize() {
		this.Errorf("could not send phase1 request to majority nodes: %v", errSend)
		return nil, nil, errSend
	}
	this.Infof("sent phase1 request %s to acceptors %v", reqHeader,
		phase1AcceptorList)

	var acceptorList []string
	maxVotedBallot := int64(-1)
	var maxVotedValue []byte
	responseMap := make(map[string]*thispb.Phase1Response)

	for ii := 0; ii < count && len(responseMap) < this.MajoritySize(); ii++ {
		message := thispb.PaxosMessage{}
		resHeader, errRecv := msg.ReceiveProto(this.msn, reqHeader, &message)
		if errRecv != nil {
			this.Warningf("could not receive more phase1 responses for %s: %v",
				reqHeader, errRecv)
			break
		}

		acceptor := resHeader.GetMessengerId()
		if _, ok := responseMap[acceptor]; ok {
			this.Warningf("duplicate phase1 response from %s (ignored)", acceptor)
			continue
		}

		if message.Phase1Response == nil {
			this.Warningf("phase1 response data is empty from %s (ignored)",
				acceptor)
			continue
		}

		response := message.GetPhase1Response()
		if response.PromisedBallot == nil {
			this.Warningf("phase1 response from %s has no promise ballot", acceptor)
			continue
		}

		promisedBallot := response.GetPromisedBallot()
		if promisedBallot > ballot {
			this.Warningf("acceptor %s has moved on to ballot %d", acceptor,
				promisedBallot)
			break
		}

		if promisedBallot < ballot {
			this.Errorf("acceptor %s did not promise this ballot %d", acceptor,
				ballot)
			continue
		}

		// We received a promise from this acceptor.
		acceptorList = append(acceptorList, acceptor)
		responseMap[acceptor] = response

		// If there was a voted value already, we need to pick the max voted value.
		if response.VotedBallot != nil {
			votedBallot := response.GetVotedBallot()
			if votedBallot > maxVotedBallot {
				maxVotedBallot = votedBallot
				maxVotedValue = response.GetVotedValue()
			}
		}
	}

	if len(responseMap) < this.MajoritySize() {
		this.Warningf("could not get majority phase1 votes %v for ballot %d",
			responseMap, ballot)
		return nil, nil, errs.ErrRetry
	}

	if maxVotedValue == nil {
		this.Infof("no prior value was chosen as per phase1 responses %v",
			responseMap)
	} else {
		this.Infof("value [%s] could have been chosen as per phase1 responses %v",
			maxVotedValue, responseMap)
	}

	return maxVotedValue, acceptorList, nil
}