Golang common.Message類代碼示例

func (tfh *TestFileHandler) HandleMessage(payload []byte) {
	m := new(common.Message)
	m.Destination = tfh.dest
	m.Payload = []byte(tfh.data)
	tfh.tcpServ.SendMessage(m)

	tfh.done <- true
}

// Announce ourself to the bootstrap address, who will announce us to the quorum
func (s *State) JoinSia() (err error) {
	// Send join message to bootstrap address
	m := new(common.Message)
	m.Destination.Id = bootstrapId
	m.Destination.Host = bootstrapHost
	m.Destination.Port = bootstrapPort
	m.Payload = append([]byte(string(joinSia)), s.self.marshal()...)
	err = s.messageRouter.SendMessage(m)
	return
}

// Takes a payload and sends it in a message to every participant in the quorum
func (s *State) broadcast(payload []byte) {
	s.participantsLock.RLock()
	for i := range s.participants {
		if s.participants[i] != nil {
			m := new(common.Message)
			m.Payload = payload
			m.Destination = s.participants[i].address
			err := s.messageRouter.SendMessage(m)
			if err != nil {
				log.Errorln("messageSender returning an error")
			}
		}
	}
	s.participantsLock.RUnlock()
}

// DownloadFile retrieves the erasure-coded segments corresponding to a given file from a quorum.
// It reconstructs the original file from the segments using erasure.RebuildSector().
func DownloadFile(mr common.MessageRouter, fileHash crypto.Hash, length int, k int, quorum [common.QuorumSize]common.Address) (fileData []byte, err error) {
	// spawn a separate thread for each segment
	for i := range quorum {
		go func() {
			// send request
			m := new(common.Message)
			m.Destination = quorum[i]
			m.Payload = []byte{0x01}
			m.Payload = append(m.Payload, fileHash[:]...)
			mr.SendMessage(m)
			// wait for response
		}()
	}
	return
}

// TestTCPDownloadFile tests the NewTCPServer and DownloadFile functions.
// NewTCPServer must properly initialize a TCP server.
// UploadFile splits a file into erasure-coded segments and distributes them across a quorum.
// k is the number of non-redundant segments.
// The file is padded to satisfy the erasure-coding requirements that:
//     len(fileData) = k*bytesPerSegment, and:
//     bytesPerSegment % 64 = 0
func UploadFile(mr common.MessageRouter, file *os.File, k int, quorum [common.QuorumSize]common.Address) (bytesPerSegment int, err error) {
	// read file
	fileInfo, err := file.Stat()
	if err != nil {
		return
	}
	if fileInfo.Size() > int64(common.QuorumSize*common.MaxSegmentSize) {
		err = fmt.Errorf("File exceeds maximum per-quorum size")
		return
	}
	fileData := make([]byte, fileInfo.Size())
	_, err = io.ReadFull(file, fileData)
	if err != nil {
		return
	}

	// calculate EncodeRing parameters, padding file if necessary
	bytesPerSegment = len(fileData) / k
	if bytesPerSegment%64 != 0 {
		bytesPerSegment += 64 - (bytesPerSegment % 64)
		padding := k*bytesPerSegment - len(fileData)
		fileData = append(fileData, bytes.Repeat([]byte{0x00}, padding)...)
	}

	// create erasure-coded segments
	segments, err := erasure.EncodeRing(k, bytesPerSegment, fileData)
	if err != nil {
		return
	}

	// for now we just send segment i to node i
	// this may need to be randomized for security
	for i := range quorum {
		m := new(common.Message)
		m.Destination = quorum[i]
		m.Payload = append([]byte{byte(i)}, []byte(segments[i])...)
		err = mr.SendMessage(m)
		if err != nil {
			return
		}
	}

	return
}

func (s *State) announceSignedHeartbeat(sh *signedHeartbeat) {
	for i := range s.participants {
		if s.participants[i] != nil {
			payload, err := sh.marshal()
			if err != nil {
				log.Fatalln(err)
			}

			m := new(common.Message)
			m.Payload = append([]byte{byte(1)}, payload...)
			m.Destination = s.participants[i].Address
			//time.Sleep(time.Millisecond) // prevents panics. No idea where original source of bug is.
			err = s.messageSender.SendMessage(m)
			if err != nil {
				log.Fatalln("Error while sending message")
			}
		}
	}
}

// Add a participant to the state, tell the participant about ourselves
func (s *State) addNewParticipant(payload []byte) {
	// extract index and participant object from payload
	participantIndex := payload[0]
	p, err := unmarshalParticipant(payload[1:])
	if err != nil {
		return
	}

	// for this participant, make the heartbeat map and add the default heartbeat
	hb := new(heartbeat)
	emptyHash, err := crypto.CalculateTruncatedHash(hb.entropyStage2[:])
	hb.entropyStage1 = emptyHash
	s.heartbeatsLock.Lock()
	s.participantsLock.Lock()
	s.heartbeats[participantIndex] = make(map[crypto.TruncatedHash]*heartbeat)
	s.heartbeats[participantIndex][emptyHash] = hb
	s.heartbeatsLock.Unlock()

	if *p == *s.self {
		// add our self object to the correct index in participants
		s.participants[participantIndex] = s.self
		s.tickingLock.Lock()
		s.ticking = true
		s.tickingLock.Unlock()

		go s.tick()
	} else {
		// add the participant to participants
		s.participants[participantIndex] = p

		// tell the new guy about ourselves
		m := new(common.Message)
		m.Destination = p.address
		m.Payload = append([]byte(string(newParticipant)), s.self.marshal()...)
		s.messageRouter.SendMessage(m)
	}
	s.participantsLock.Unlock()
}

func (a *Announce) SendOutAnnounce(recipients []*Participant) error {
	//TODO Add code to actually send out to participants when it works.
	server, err := network.NewTCPServer(7777)
	if err != nil {
		log.Fatal("TCP Server not initialized")
	}
	for _, i := range recipients {
		s, err := json.Marshal(a)
		s = []byte(string(rune(0)) + string(s))
		if err != nil {
			log.Fatal(err)
		}
		c := new(common.Message)
		c.Payload = s
		c.Destination = i.Address
		err = server.SendMessage(c)
		if err != nil {
			log.Fatal(err)
		}
	}

	return nil
}