Golang Header.GetMessengerId方法代码示例

// CloseMessage releases a message header.
//
// header: Message header.
//
// Returns nil on success.
func (this *Messenger) CloseMessage(header *msgpb.Header) error {
	if header.GetMessengerId() != this.uid {
		this.Errorf("message header %s is not created by this messenger", header)
		return errs.ErrInvalid
	}

	if header.Request == nil {
		return nil
	}
	//
	// Remove the request and its response channel from live requests map.
	//
	lock, errLock := this.ctlr.Lock("this.requestMap")
	if errLock != nil {
		return errLock
	}
	defer lock.Unlock()

	requestID := header.GetMessageId()
	responseCh, found := this.requestMap[requestID]
	if !found {
		return nil
	}

	close(responseCh)
	delete(this.requestMap, requestID)
	return nil
}

// StatusRPC implements the Election.Status rpc.
func (this *Election) StatusRPC(reqHeader *msgpb.Header,
	request *thispb.StatusRequest) error {

	if !this.InCommittee() {
		this.Errorf("this election object is not a committee member")
		return errs.ErrNotExist
	}

	lock := this.ctlr.ReadLock("election")
	round := this.CurrentRound()
	winner := this.currentWinner
	lock.Unlock()

	// Committee members always have up to date election information.
	response := thispb.StatusResponse{}
	response.ElectionRound = proto.Int64(round)
	response.ElectionWinner = proto.String(winner)
	message := thispb.ElectionMessage{}
	message.StatusResponse = &response

	clientID := reqHeader.GetMessengerId()
	if err := msg.SendResponseProto(this.msn, reqHeader, &message); err != nil {
		this.Errorf("could not send status response to %s: %v", clientID, err)
		return err
	}
	return nil
}

// Phase1RPC handles ClassicPaxos.Phase1 rpc.
func (this *Paxos) Phase1RPC(header *msgpb.Header,
	request *thispb.Phase1Request) (status error) {

	if !this.IsAcceptor() {
		this.Errorf("this paxos instance is not an acceptor; rejecting %s", header)
		return errs.ErrInvalid
	}

	lock, errLock := this.ctlr.TimedLock(msg.RequestTimeout(header),
		"acceptor")
	if errLock != nil {
		return errLock
	}
	defer lock.Unlock()

	clientID := header.GetMessengerId()
	respond := func() error {
		response := thispb.Phase1Response{}
		response.PromisedBallot = proto.Int64(this.promisedBallot)
		if this.votedBallot >= 0 {
			response.VotedBallot = proto.Int64(this.votedBallot)
			response.VotedValue = this.votedValue
		}
		message := thispb.PaxosMessage{}
		message.Phase1Response = &response
		errSend := msg.SendResponseProto(this.msn, header, &message)
		if errSend != nil {
			this.Errorf("could not send phase1 response to %s: %v", clientID,
				errSend)
			return errSend
		}
		return nil
	}

	ballot := request.GetBallotNumber()
	if ballot < this.promisedBallot {
		this.Warningf("phase1 request from %s is ignored due to stale ballot %d",
			clientID, ballot)
		return respond()
	}

	if ballot == this.promisedBallot {
		this.Warningf("duplicate phase1 request from client %s with an already "+
			"promised ballot number %d", clientID, ballot)
		return respond()
	}

	// Save the promise into the wal.
	change := thispb.AcceptorChange{}
	change.PromisedBallot = proto.Int64(ballot)
	if err := this.doUpdateAcceptor(&change); err != nil {
		this.Errorf("could not update acceptor state: %v", err)
		return err
	}

	this.Infof("this acceptor has now promised higher ballot %d from %s", ballot,
		clientID)
	return respond()
}

// SendResponse sends a response message to the source of a request.
//
// msn: The Messenger.
//
// reqHeader: Message header for a request.
//
// data: User data to include in the response.
//
// Returns nil on success.
func SendResponse(msn Messenger, reqHeader *msgpb.Header, data []byte) error {
	if reqHeader.Request == nil {
		msn.Errorf("message header %s is not a request", reqHeader)
		return errs.ErrInvalid
	}
	resHeader := msn.NewResponse(reqHeader)
	return msn.Send(reqHeader.GetMessengerId(), resHeader, data)
}

func (this *RPCServer) Dispatch(header *msgpb.Header, data []byte) error {
	response := this.NewResponse(header)
	sourceID := header.GetMessengerId()
	if err := this.Send(sourceID, response, []byte("response-data")); err != nil {
		this.Errorf("could not send response for %s to messenger %s: %v", header,
			sourceID, err)
		return err
	}
	return nil
}

// ElectRPC implements the Election.Elect rpc.
func (this *Election) ElectRPC(reqHeader *msgpb.Header,
	request *thispb.ElectRequest) (status error) {

	if !this.InCommittee() {
		return errs.ErrInvalid
	}

	round := request.GetElectionRound()
	current := this.CurrentRound()
	if round != current+1 {
		this.Errorf("could not begin election round %d because current round "+
			"is only at %d", round, current)
		return errs.ErrStale
	}

	uid := this.PaxosUIDFromElectionRound(round)
	paxos, errGet := this.GetPaxosInstance(uid)
	if errGet != nil {
		this.Errorf("could not find paxos instance for uid %s: %v", uid, errGet)
		return errGet
	}

	this.Infof("starting new election for round %d using paxos instance %s",
		round, uid)

	clientID := reqHeader.GetMessengerId()
	proposedValue := []byte(clientID)
	chosenValue, errPropose := paxos.Propose(proposedValue,
		msg.RequestTimeout(reqHeader))
	if errPropose != nil {
		this.Errorf("could not propose %s as the leader for election round %d: %v",
			proposedValue, round, errPropose)
		return errPropose
	}
	winner := string(chosenValue)

	// Send the election result.
	response := thispb.ElectResponse{}
	response.ElectionRound = proto.Int64(round)
	response.ElectionWinner = proto.String(winner)
	message := thispb.ElectionMessage{}
	message.ElectResponse = &response
	if err := msg.SendResponseProto(this.msn, reqHeader, &message); err != nil {
		this.Errorf("could not send election response to %s: %v", clientID, err)
		return err
	}
	return nil
}

// LearnRPC handles ClassicPaxos.Learn rpc.
func (this *Paxos) LearnRPC(header *msgpb.Header,
	request *thispb.LearnRequest) (status error) {

	if !this.IsLearner() {
		this.Errorf("this paxos instance is not a learner; rejecting %s", header)
		return errs.ErrInvalid
	}

	lock, errLock := this.ctlr.TimedLock(msg.RequestTimeout(header), "learner")
	if errLock != nil {
		return errLock
	}
	defer lock.Unlock()

	acceptor := header.GetMessengerId()
	if this.chosenValue == nil {
		change := thispb.LearnerChange{}
		change.VotedBallotList = request.VotedBallotList
		change.VotedValueList = request.VotedValueList
		change.VotedAcceptor = proto.String(acceptor)
		if err := this.doUpdateLearner(&change); err != nil {
			this.Errorf("could not update learner state: %v", err)
			return err
		}
	}

	response := thispb.LearnResponse{}
	if this.chosenValue != nil {
		response.KnowsChosenValue = proto.Bool(true)
	}
	message := thispb.PaxosMessage{}
	message.LearnResponse = &response
	errSend := msg.SendResponseProto(this.msn, header, &message)
	if errSend != nil {
		this.Errorf("could not respond to learn request from %s: %v", acceptor,
			errSend)
		return errSend
	}
	return nil
}

// DispatchRequest invokes the target (exported) function identified in the
// request message.
//
// header: Message header for the request.
//
// data: User data in the request.
//
// Returns dispatch operation status and the handler status.
func (this *Messenger) DispatchRequest(header *msgpb.Header,
	data []byte) (msnStatus, appStatus error) {

	defer func() {
		if msnStatus != nil || appStatus != nil {
			failure := this.NewResponse(header)
			if msnStatus != nil {
				failure.Response.MessengerStatus = errs.MakeProtoFromError(msnStatus)
			} else {
				failure.Response.HandlerStatus = errs.MakeProtoFromError(appStatus)
			}

			sourceID := header.GetMessengerId()
			if err := this.Send(sourceID, failure, nil); err != nil {
				this.Errorf("could not reply failure %s for %s from %s (ignored)",
					failure, header, sourceID)
			}
		}
	}()

	lock, errLock := this.ctlr.Lock("this.exportMap")
	if errLock != nil {
		return errLock, nil
	}
	defer lock.Unlock()

	request := header.GetRequest()
	classID := request.GetClassId()
	methodName := request.GetMethodName()
	if len(classID) == 0 || len(methodName) == 0 {
		this.Errorf("header %s is invalid because class id and/or method name "+
			"are empty", header)
		msnStatus = errs.NewErrInvalid("class id and/or method name cannot be " +
			"empty")
		return msnStatus, nil
	}

	methodMap, found := this.exportMap[classID]
	if !found {
		this.Errorf("no class with id %s was registered", classID)
		msnStatus = errs.NewErrNotExist("no class with id %s was registered",
			classID)
		return msnStatus, nil
	}

	handler, found := methodMap[methodName]
	if !found {
		this.Errorf("class %s has no method named %s", classID, methodName)
		msnStatus = errs.NewErrNotExist("class %s has no method named %s", classID,
			methodName)
		return msnStatus, nil
	}

	// Close the lock early to release the resources.
	lock.Unlock()

	appStatus = handler.Dispatch(header, data)
	if appStatus != nil {
		this.Warningf("request %s failed with status %v", header, appStatus)
	}
	return nil, appStatus
}

// Phase2RPC handles ClassicPaxos.Phase2 rpc.
func (this *Paxos) Phase2RPC(header *msgpb.Header,
	request *thispb.Phase2Request) (status error) {

	if !this.IsAcceptor() {
		this.Errorf("this paxos instance is not an acceptor; rejecting %s", header)
		return errs.ErrInvalid
	}

	lock, errLock := this.ctlr.TimedLock(msg.RequestTimeout(header), "acceptor")
	if errLock != nil {
		return errLock
	}
	defer lock.Unlock()

	clientID := header.GetMessengerId()
	respond := func() error {
		response := thispb.Phase2Response{}
		response.PromisedBallot = proto.Int64(this.promisedBallot)
		if this.votedBallot >= 0 {
			response.VotedBallot = proto.Int64(this.votedBallot)
			response.VotedValue = this.votedValue
		}
		message := thispb.PaxosMessage{}
		message.Phase2Response = &response
		errSend := msg.SendResponseProto(this.msn, header, &message)
		if errSend != nil {
			this.Errorf("could not send phase2 response to %s: %v", clientID,
				errSend)
			return errSend
		}
		return nil
	}

	ballot := request.GetBallotNumber()
	if ballot < this.promisedBallot {
		this.Warningf("phase2 request from %s is ignored due to stale ballot %d",
			clientID, ballot)
		return respond()
	}

	if ballot > this.promisedBallot {
		this.Errorf("phase2 request from client %s without acquiring a prior "+
			"promise", clientID)
		return respond()
	}
	value := request.GetProposedValue()

	// Save the phase2 vote into the wal.
	change := thispb.AcceptorChange{}
	change.VotedBallot = proto.Int64(ballot)
	change.VotedValue = value
	if err := this.doUpdateAcceptor(&change); err != nil {
		this.Errorf("could not update acceptor state: %v", err)
		return err
	}

	this.Infof("this acceptor has voted for %d in ballot %s", ballot, value)
	if err := respond(); err != nil {
		return err
	}

	// Schedule a notification to all learners.
	_ = this.alarm.ScheduleAt(this.uid, time.Now(), this.NotifyAllLearners)
	return nil
}