Golang protocol.Request类代码示例

func (self *log) appendRequest(request *protocol.Request, shardId uint32) error {
	bytes, err := request.Encode()

	if err != nil {
		return err
	}
	// every request is preceded with the length, shard id and the request number
	hdr := &entryHeader{
		shardId:       shardId,
		requestNumber: request.GetRequestNumber(),
		length:        uint32(len(bytes)),
	}
	writtenHdrBytes, err := hdr.Write(self.file)
	if err != nil {
		logger.Error("Error while writing header: %s", err)
		return err
	}
	written, err := self.file.Write(bytes)
	if err != nil {
		logger.Error("Error while writing request: %s", err)
		return err
	}
	if written < len(bytes) {
		err = fmt.Errorf("Couldn't write entire request")
		logger.Error("Error while writing request: %s", err)
		return err
	}
	self.fileSize += uint64(writtenHdrBytes + written)
	return nil
}

func (self *log) appendRequest(request *protocol.Request, shardId uint32) (uint32, error) {
	self.assignSequenceNumbers(shardId, request)
	bytes, err := request.Encode()

	if err != nil {
		return 0, err
	}
	requestNumber := self.state.getNextRequestNumber()
	// every request is preceded with the length, shard id and the request number
	hdr := &entryHeader{
		shardId:       shardId,
		requestNumber: requestNumber,
		length:        uint32(len(bytes)),
	}
	writtenHdrBytes, err := hdr.Write(self.file)
	if err != nil {
		logger.Error("Error while writing header: %s", err)
		return 0, err
	}
	written, err := self.file.Write(bytes)
	if err != nil {
		logger.Error("Error while writing request: %s", err)
		return 0, err
	}
	if written < len(bytes) {
		err = fmt.Errorf("Couldn't write entire request")
		logger.Error("Error while writing request: %s", err)
		return 0, err
	}
	self.fileSize += uint64(writtenHdrBytes + written)
	self.conditionalBookmarkAndIndex()
	return requestNumber, nil
}

func (self *ProtobufRequestHandler) HandleRequest(request *protocol.Request, conn net.Conn) error {
	if *request.Type == protocol.Request_WRITE {
		shard := self.clusterConfig.GetLocalShardById(*request.ShardId)
		log.Debug("HANDLE: (%d):%d:%v", self.clusterConfig.LocalServer.Id, request.GetId(), shard)
		err := shard.WriteLocalOnly(request)
		if err != nil {
			log.Error("ProtobufRequestHandler: error writing local shard: ", err)
			return err
		}
		response := &protocol.Response{RequestId: request.Id, Type: &self.writeOk}
		return self.WriteResponse(conn, response)
	} else if *request.Type == protocol.Request_DROP_DATABASE {
		go self.handleDropDatabase(request, conn)
		return nil
	} else if *request.Type == protocol.Request_QUERY {
		go self.handleQuery(request, conn)
	} else if *request.Type == protocol.Request_HEARTBEAT {
		response := &protocol.Response{RequestId: request.Id, Type: &heartbeatResponse}
		return self.WriteResponse(conn, response)
	} else {
		log.Error("unknown request type: %v", request)
		return errors.New("Unknown request type")
	}
	return nil
}

func (self *CoordinatorImpl) ReplicateWrite(request *protocol.Request) error {
	id := atomic.AddUint32(&self.requestId, uint32(1))
	request.Id = &id
	location := common.RingLocation(request.Database, request.Series.Name, request.Series.Points[0].Timestamp)
	replicas := self.clusterConfiguration.GetServersByRingLocation(request.Database, &location)
	request.Type = &replicateWrite
	self.sendRequestToReplicas(request, replicas)
	return nil
}

func (self *CoordinatorImpl) ReplicateDelete(request *protocol.Request) error {
	id := atomic.AddUint32(&self.requestId, uint32(1))
	request.Id = &id
	server := self.clusterConfiguration.GetServerById(request.OwnerServerId)
	_, replicas := self.clusterConfiguration.GetReplicas(server, request.Database)
	request.Type = &replicateDelete
	self.sendRequestToReplicas(request, replicas)
	return nil
}

func (self *CoordinatorImpl) sendRequestToReplicas(request *protocol.Request, replicas []*ClusterServer) {
	for _, server := range replicas {
		if server.Id != self.clusterConfiguration.localServerId {
			err := server.MakeRequest(request, nil)
			if err != nil {
				log.Warn("REPLICATION ERROR: ", request.GetSequenceNumber(), err)
			}
		}
	}
}

func (self *ClusterServer) Write(request *protocol.Request) error {
	responseChan := make(chan *protocol.Response)
	err := self.connection.MakeRequest(request, responseChan)
	if err != nil {
		return err
	}
	log.Debug("Waiting for response to %d", request.GetRequestNumber())
	response := <-responseChan
	if response.ErrorMessage != nil {
		return errors.New(*response.ErrorMessage)
	}
	return nil
}

func (self *CoordinatorImpl) proxyWrite(clusterServer *ClusterServer, request *protocol.Request) error {
	originatingServerId := request.OriginatingServerId
	request.OriginatingServerId = nil
	defer func() { request.OriginatingServerId = originatingServerId }()

	responseChan := make(chan *protocol.Response, 1)
	clusterServer.protobufClient.MakeRequest(request, responseChan)
	response := <-responseChan
	if *response.Type == protocol.Response_WRITE_OK {
		return nil
	} else {
		return errors.New(response.GetErrorMessage())
	}
}

func (self *ProtobufRequestHandler) handleWrites(request *protocol.Request, conn net.Conn) {
	shard := self.clusterConfig.GetLocalShardById(*request.ShardId)
	log.Debug("HANDLE: (%d):%d:%v", self.clusterConfig.LocalServer.Id, request.GetId(), shard)
	err := shard.WriteLocalOnly(request)
	var errorMsg *string
	if err != nil {
		log.Error("ProtobufRequestHandler: error writing local shard: %s", err)
		errorMsg = protocol.String(err.Error())
	}
	response := &protocol.Response{RequestId: request.Id, Type: &self.writeOk, ErrorMessage: errorMsg}
	if err := self.WriteResponse(conn, response); err != nil {
		log.Error("ProtobufRequestHandler: error writing local shard: %s", err)
	}
}

// Makes a request to the server. If the responseStream chan is not nil it will expect a response from the server
// with a matching request.Id. The REQUEST_RETRY_ATTEMPTS constant of 3 and the RECONNECT_RETRY_WAIT of 100ms means
// that an attempt to make a request to a downed server will take 300ms to time out.
func (self *ProtobufClient) MakeRequest(request *protocol.Request, responseStream chan *protocol.Response) error {
	if request.Id == nil {
		id := atomic.AddUint32(&self.lastRequestId, uint32(1))
		request.Id = &id
	}
	if responseStream != nil {
		self.requestBufferLock.Lock()

		// this should actually never happen. The sweeper should clear out dead requests
		// before the uint32 ids roll over.
		if oldReq, alreadyHasRequestById := self.requestBuffer[*request.Id]; alreadyHasRequestById {
			message := "already has a request with this id, must have timed out"
			log.Error(message)
			oldReq.responseChan <- &protocol.Response{Type: &endStreamResponse, ErrorMessage: &message}
		}
		self.requestBuffer[*request.Id] = &runningRequest{timeMade: time.Now(), responseChan: responseStream, request: request}
		self.requestBufferLock.Unlock()
	}

	data, err := request.Encode()
	if err != nil {
		return err
	}

	conn := self.getConnection()
	if conn == nil {
		conn = self.reconnect()
		if conn == nil {
			return fmt.Errorf("Failed to connect to server %s", self.hostAndPort)
		}
	}

	if self.writeTimeout > 0 {
		conn.SetWriteDeadline(time.Now().Add(self.writeTimeout))
	}
	buff := bytes.NewBuffer(make([]byte, 0, len(data)+8))
	binary.Write(buff, binary.LittleEndian, uint32(len(data)))
	_, err = conn.Write(append(buff.Bytes(), data...))

	if err == nil {
		return nil
	}

	// if we got here it errored out, clear out the request
	self.requestBufferLock.Lock()
	delete(self.requestBuffer, *request.Id)
	self.requestBufferLock.Unlock()
	self.reconnect()
	return err
}

func (self *ShardData) forwardRequest(request *p.Request) ([]<-chan *p.Response, []uint32, error) {
	ids := []uint32{}
	responses := []<-chan *p.Response{}
	for _, server := range self.clusterServers {
		responseChan := make(chan *p.Response, 1)
		// do this so that a new id will get assigned
		request.Id = nil
		log.Debug("Forwarding request %s to %d", request.GetDescription(), server.Id)
		server.MakeRequest(request, responseChan)
		responses = append(responses, responseChan)
		ids = append(ids, server.Id)
	}
	return responses, ids, nil
}

// This method never blocks. It'll buffer writes until they fill the buffer then drop the on the
// floor and let the background goroutine replay from the WAL
func (self *WriteBuffer) Write(request *protocol.Request) {
	self.shardLastRequestNumber[request.GetShardId()] = request.GetRequestNumber()
	select {
	case self.writes <- request:
		return
	default:
		select {
		case self.stoppedWrites <- *request.RequestNumber:
			return
		default:
			return
		}
	}
}

func (self *LevelDbDatastore) LogRequestAndAssignSequenceNumber(request *protocol.Request, replicationFactor *uint8, ownerServerId *uint32) error {
	// log to this key structure on a different DB sharded by day: <cluster version><owner id><sequence server id><replication sequence>
	var numberKey []byte
	if request.SequenceNumber == nil {
		sequenceNumber, err := self.AtomicIncrement(self.keyForOwnerAndServerSequenceNumber(request.ClusterVersion, replicationFactor, ownerServerId, request.OriginatingServerId), 1)
		if err != nil {
			return err
		}
		request.SequenceNumber = &sequenceNumber
	} else {
		// this is for a replicated write, ensure that it's the next in line for this owner and server
		name := self.keyForOwnerAndServerSequenceNumber(request.ClusterVersion, replicationFactor, ownerServerId, request.OriginatingServerId)
		numberKey = append(ATOMIC_INCREMENT_PREFIX, []byte(name)...)
		numberBytes, err := self.db.Get(self.readOptions, numberKey)
		if err != nil {
			return err
		}
		previousSequenceNumber := self.bytesToCurrentNumber(numberBytes)
		if previousSequenceNumber+uint64(1) != *request.SequenceNumber {
			return SequenceMissingRequestsError{"Missing requests between last seen and this one.", previousSequenceNumber}
		}
	}

	self.requestLogLock.RLock()
	requestLog := self.currentRequestLog
	self.requestLogLock.RUnlock()

	// proxied writes should be logged as replicated ones. That's what is expected if they're replayed later
	if *request.Type == protocol.Request_PROXY_WRITE {
		request.Type = &replicateWrite
	}

	data, err := request.Encode()
	if err != nil {
		return err
	}

	key := self.requestLogKey(request.ClusterVersion, request.OriginatingServerId, ownerServerId, request.SequenceNumber, replicationFactor)
	err = requestLog.db.Put(self.writeOptions, key, data)
	if err != nil {
		return err
	}
	if numberKey != nil {
		currentNumberBuffer := bytes.NewBuffer(make([]byte, 0, 8))
		binary.Write(currentNumberBuffer, binary.BigEndian, *request.SequenceNumber)
		self.db.Put(self.writeOptions, numberKey, currentNumberBuffer.Bytes())
	}
	return nil
}

func (self *ShardData) Write(request *protocol.Request) error {
	request.ShardId = &self.id
	requestNumber, err := self.wal.AssignSequenceNumbersAndLog(request, self)
	if err != nil {
		return err
	}
	request.RequestNumber = &requestNumber
	if self.store != nil {
		self.store.BufferWrite(request)
	}
	for _, server := range self.clusterServers {
		server.BufferWrite(request)
	}
	return nil
}

func (self *LevelDbDatastore) LogRequestAndAssignSequenceNumber(request *protocol.Request, replicationFactor *uint8, ownerServerId *uint32) error {
	// log to this key structure on a different DB sharded by day: <cluster version><owner id><sequence server id><replication sequence>
	updateSequenceNumber := false
	if request.SequenceNumber == nil {
		sequenceNumber, err := self.AtomicIncrement(self.keyForOwnerAndServerSequenceNumber(request.ClusterVersion, replicationFactor, ownerServerId, request.OriginatingServerId), 1)
		if err != nil {
			return err
		}
		request.SequenceNumber = &sequenceNumber
	} else {
		updateSequenceNumber = true
		previousSequenceNumber, err := self.CurrentSequenceNumber(request.ClusterVersion, replicationFactor, ownerServerId, request.OriginatingServerId)
		if err != nil {
			return err
		}
		// Do a less than comparison because it's ok if we're just getting the same write again. As long as we haven't missed one.
		if previousSequenceNumber+uint64(1) < *request.SequenceNumber {
			log.Warn("MISSING REQUESTS: %d, %d", previousSequenceNumber, *request.SequenceNumber)
			return SequenceMissingRequestsError{"Missing requests between last seen and this one.", previousSequenceNumber, *request.SequenceNumber}
		}
	}

	self.requestLogLock.RLock()
	requestLog := self.currentRequestLog
	self.requestLogLock.RUnlock()

	// proxied writes should be logged as replicated ones. That's what is expected if they're replayed later
	if *request.Type == protocol.Request_PROXY_WRITE {
		request.Type = &replicateWrite
	}

	data, err := request.Encode()
	if err != nil {
		return err
	}

	key := NewWALKey(request.ClusterVersion, request.OriginatingServerId, ownerServerId, request.SequenceNumber, replicationFactor)
	err = requestLog.db.Put(self.writeOptions, key, data)
	if err != nil {
		return err
	}
	if updateSequenceNumber {
		return self.updateSequenceNumber(request.ClusterVersion, replicationFactor, ownerServerId, request.OriginatingServerId, *request.SequenceNumber)
	}
	return nil
}