Scaling
这一部分的实现跟之前有显著的不同，先从入口shardingsphere-scaling-bootstrap ScalingServerBootstrap 看下，就是先初始化配置，再启动一个netty服务
@NoArgsConstructor(access = AccessLevel.PRIVATE) @Slf4j public final class ScalingServerBootstrap { public static void main(final String[] args) { // CHECKSTYLE:ON log.info("ShardingSphere-Scaling Server Startup"); ServerConfigurationInitializer.init(); startScalingServer(); } @SneakyThrows(InterruptedException.class) private static void startScalingServer() { log.info("Start scaling server"); EventLoopGroup bossGroup = new NioEventLoopGroup(1); EventLoopGroup workerGroup = new NioEventLoopGroup(); try { ServerBootstrap bootstrap = new ServerBootstrap(); bootstrap.option(ChannelOption.SO_BACKLOG, 1024); bootstrap.group(bossGroup, workerGroup) .channel(NioServerSocketChannel.class) .handler(new LoggingHandler(LogLevel.INFO)) .childHandler(new HttpServerInitializer()); int port = ScalingContext.getInstance().getServerConfig().getPort(); Channel channel = bootstrap.bind(port).sync().channel(); log.info("ShardingSphere-Scaling is server on http://127.0.0.1:{}/", port); channel.closeFuture().sync(); } finally { bossGroup.shutdownGracefully(); workerGroup.shutdownGracefully(); } } }
继续跟进，看起来似乎就是解码http请求，再处理下
public final class HttpServerInitializer extends ChannelInitializer<SocketChannel> { @Override protected void initChannel(final SocketChannel socketChannel) { ChannelPipeline channelPipeline = socketChannel.pipeline(); channelPipeline.addLast(new HttpServerCodec()); channelPipeline.addLast(new HttpObjectAggregator(65536)); channelPipeline.addLast(new HttpServerHandler()); } }
进到最后一个handler，就十分清晰了，得到请求后，按照路径对应执行不同的/scaling/job/***
public final class HttpServerHandler extends SimpleChannelInboundHandler<FullHttpRequest> { private static final Gson GSON = new GsonBuilder().disableHtmlEscaping().serializeNulls().setLongSerializationPolicy(LongSerializationPolicy.STRING).create(); private final ScalingAPI scalingAPI = ScalingAPIFactory.getScalingAPI(); @Override protected void channelRead0(final ChannelHandlerContext context, final FullHttpRequest request) { String requestPath = request.uri().toLowerCase(); String requestBody = request.content().toString(CharsetUtil.UTF_8); log.info("Http request path: {}", requestPath); log.info("Http request body: {}", requestBody); if ("/scaling/job/start".equalsIgnoreCase(requestPath) && request.method().equals(HttpMethod.POST)) { startJob(context, requestBody); return; } if ("/scaling/job/list".equalsIgnoreCase(requestPath)) { listJobs(context); return; } if (requestPath.startsWith("/scaling/job/progress/")) { getJobProgress(context, requestPath); return; } if (requestPath.startsWith("/scaling/job/stop/")) { stopJob(context, requestPath); return; } if (requestPath.contains("/scaling/job/check/")) { checkJob(context, requestPath); return; } if (requestPath.contains("/scaling/job/reset/")) { resetJob(context, requestPath); return; } response(ResponseContentUtil.handleBadRequest("Not support request!"), context, HttpResponseStatus.BAD_REQUEST); } private void startJob(final ChannelHandlerContext context, final String requestBody) { Optional<Long> jobId = scalingAPI.start(GSON.fromJson(requestBody, JobConfiguration.class)); if (jobId.isPresent()) { response(ResponseContentUtil.build(jobId.get()), context, HttpResponseStatus.OK); return; } response(ResponseContentUtil.handleBadRequest("Invalid scaling job config!"), context, HttpResponseStatus.BAD_REQUEST); } private void listJobs(final ChannelHandlerContext context) { List<JobInfo> jobContexts = scalingAPI.list(); response(ResponseContentUtil.build(jobContexts), context, HttpResponseStatus.OK); } private void getJobProgress(final ChannelHandlerContext context, final String requestPath) { try { response(ResponseContentUtil.build(scalingAPI.getProgress(getJobId(requestPath))), context, HttpResponseStatus.OK); } catch (final ScalingJobNotFoundException ex) { response(ResponseContentUtil.handleBadRequest(ex.getMessage()), context, HttpResponseStatus.BAD_REQUEST); } } private void stopJob(final ChannelHandlerContext context, final String requestPath) { scalingAPI.stop(getJobId(requestPath)); response(ResponseContentUtil.success(), context, HttpResponseStatus.OK); } private void checkJob(final ChannelHandlerContext context, final String requestPath) { try { response(ResponseContentUtil.build(scalingAPI.dataConsistencyCheck(getJobId(requestPath))), context, HttpResponseStatus.OK); } catch (final ScalingJobNotFoundException ex) { response(ResponseContentUtil.handleBadRequest(ex.getMessage()), context, HttpResponseStatus.BAD_REQUEST); } } private void resetJob(final ChannelHandlerContext context, final String requestPath) { try { scalingAPI.reset(getJobId(requestPath)); response(ResponseContentUtil.success(), context, HttpResponseStatus.OK); } catch (final ScalingJobNotFoundException | SQLException ex) { response(ResponseContentUtil.handleBadRequest(ex.getMessage()), context, HttpResponseStatus.BAD_REQUEST); } } private long getJobId(final String requestPath) { return Long.parseLong(requestPath.split("/")[4]); } private void response(final Object content, final ChannelHandlerContext context, final HttpResponseStatus status) { FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, status, Unpooled.copiedBuffer(GSON.toJson(content), CharsetUtil.UTF_8)); response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/plain;charset=UTF-8"); HttpUtil.setContentLength(response, response.content().readableBytes()); response.headers().set(HttpHeaderNames.CONNECTION, HttpHeaderValues.KEEP_ALIVE); context.writeAndFlush(response); } @Override public void exceptionCaught(final ChannelHandlerContext context, final Throwable cause) { log.error("Http request handle occur error:", cause); response(ResponseContentUtil.handleException(cause.toString()), context, HttpResponseStatus.INTERNAL_SERVER_ERROR); context.close(); } }
具体执行已经脱离了netty应用本身，这里shardingsphere框架封装了一个ScalingAPIFactory
具体看这个类的内容，发现实际执行是依赖了ElasticJob，所有命令都相当于是注册中心协调下的job运行
@NoArgsConstructor(access = AccessLevel.PRIVATE) public final class ScalingAPIFactory { /** * Get scaling API. * * @return scaling API */ public static ScalingAPI getScalingAPI() { return ScalingAPIHolder.getInstance(); } /** * Get governance repository API. * * @return governance repository API */ public static GovernanceRepositoryAPI getGovernanceRepositoryAPI() { return GovernanceRepositoryAPIHolder.getInstance(); } /** * Get job statistics API. * * @return job statistics API */ public static JobStatisticsAPI getJobStatisticsAPI() { return ElasticJobAPIHolder.getInstance().getJobStatisticsAPI(); } /** * Get job configuration API. * * @return job configuration API */ public static JobConfigurationAPI getJobConfigurationAPI() { return ElasticJobAPIHolder.getInstance().getJobConfigurationAPI(); } /** * Get job operate API. * * @return job operate API */ public static JobOperateAPI getJobOperateAPI() { return ElasticJobAPIHolder.getInstance().getJobOperateAPI(); } /** * Get registry center. * * @return Coordinator registry center */ public static CoordinatorRegistryCenter getRegistryCenter() { return RegistryCenterHolder.getInstance(); } private static void checkServerConfig() { ServerConfiguration serverConfig = ScalingContext.getInstance().getServerConfig(); Preconditions.checkNotNull(serverConfig, "Scaling server configuration is required."); Preconditions.checkNotNull(serverConfig.getGovernanceConfig(), "Governance configuration is required."); } private static final class ScalingAPIHolder { private static volatile ScalingAPI instance; public static ScalingAPI getInstance() { if (null == instance) { synchronized (ScalingAPIFactory.class) { if (null == instance) { checkServerConfig(); instance = new ScalingAPIImpl(); } } } return instance; } } private static final class GovernanceRepositoryAPIHolder { private static volatile GovernanceRepositoryAPI instance; static { ShardingSphereServiceLoader.register(RegistryCenterRepository.class); } public static GovernanceRepositoryAPI getInstance() { if (null == instance) { synchronized (ScalingAPIFactory.class) { if (null == instance) { instance = createGovernanceRepositoryAPI(); } } } return instance; } private static GovernanceRepositoryAPI createGovernanceRepositoryAPI() { checkServerConfig(); GovernanceConfiguration governanceConfig = ScalingContext.getInstance().getServerConfig().getGovernanceConfig(); RegistryCenterConfiguration registryCenterConfig = governanceConfig.getRegistryCenterConfiguration(); RegistryCenterRepository registryCenterRepository = TypedSPIRegistry.getRegisteredService(RegistryCenterRepository.class, registryCenterConfig.getType(), registryCenterConfig.getProps()); registryCenterRepository.init(governanceConfig.getName(), registryCenterConfig); return new GovernanceRepositoryAPIImpl(registryCenterRepository); } } @Getter private static final class ElasticJobAPIHolder { private static volatile ElasticJobAPIHolder instance; private final JobStatisticsAPI jobStatisticsAPI; private final JobConfigurationAPI jobConfigurationAPI; private final JobOperateAPI jobOperateAPI; private ElasticJobAPIHolder() { checkServerConfig(); GovernanceConfiguration governanceConfig = ScalingContext.getInstance().getServerConfig().getGovernanceConfig(); String namespace = governanceConfig.getName() + ScalingConstant.SCALING_ROOT; jobStatisticsAPI = JobAPIFactory.createJobStatisticsAPI(governanceConfig.getRegistryCenterConfiguration().getServerLists(), namespace, null); jobConfigurationAPI = JobAPIFactory.createJobConfigurationAPI(governanceConfig.getRegistryCenterConfiguration().getServerLists(), namespace, null); jobOperateAPI = JobAPIFactory.createJobOperateAPI(governanceConfig.getRegistryCenterConfiguration().getServerLists(), namespace, null); } public static ElasticJobAPIHolder getInstance() { if (null == instance) { synchronized (ScalingAPIFactory.class) { if (null == instance) { instance = new ElasticJobAPIHolder(); } } } return instance; } } private static final class RegistryCenterHolder { private static volatile CoordinatorRegistryCenter instance; public static CoordinatorRegistryCenter getInstance() { if (null == instance) { synchronized (ScalingAPIFactory.class) { if (null == instance) { instance = createRegistryCenter(); } } } return instance; } private static CoordinatorRegistryCenter createRegistryCenter() { CoordinatorRegistryCenter result = new ZookeeperRegistryCenter(getZookeeperConfig()); result.init(); return result; } private static ZookeeperConfiguration getZookeeperConfig() { checkServerConfig(); GovernanceConfiguration governanceConfig = ScalingContext.getInstance().getServerConfig().getGovernanceConfig(); ZookeeperConfiguration result = new ZookeeperConfiguration(governanceConfig.getRegistryCenterConfiguration().getServerLists(), governanceConfig.getName() + ScalingConstant.SCALING_ROOT); Properties props = governanceConfig.getRegistryCenterConfiguration().getProps(); result.setMaxSleepTimeMilliseconds(getProperty(props, "max.sleep.time.milliseconds", result.getMaxSleepTimeMilliseconds())); result.setBaseSleepTimeMilliseconds(getProperty(props, "base.sleep.time.milliseconds", result.getBaseSleepTimeMilliseconds())); result.setConnectionTimeoutMilliseconds(getProperty(props, "connection.timeout.milliseconds", result.getConnectionTimeoutMilliseconds())); result.setSessionTimeoutMilliseconds(getProperty(props, "session.timeout.milliseconds", result.getSessionTimeoutMilliseconds())); return result; } private static int getProperty(final Properties props, final String key, final int defaultValue) { return Strings.isNullOrEmpty(props.getProperty(key)) ? defaultValue : Integer.parseInt(props.getProperty(key)); } } }
再看下包里的另一个文件 ScalingWorkerBootstrap，也是个有main方法的类，看名字先初始化配置再初始化工作者
@NoArgsConstructor(access = AccessLevel.PRIVATE) @Slf4j public final class ScalingWorkerBootstrap { public static void main(final String[] args) { // CHECKSTYLE:ON log.info("ShardingSphere-Scaling Worker Startup"); ServerConfigurationInitializer.init(); ScalingWorker.init(); wait0(); } private static synchronized void wait0() { try { ScalingWorkerBootstrap.class.wait(); } catch (final InterruptedException ignored) { } } }
工作者是做什么工作的？通过事件、定时任务、注册中心驱动整个job的执行周期
@Slf4j public final class ScalingWorker { private static final ScalingWorker INSTANCE = new ScalingWorker(); private final ScalingAPI scalingAPI = ScalingAPIFactory.getScalingAPI(); /** * Init scaling worker. */ public static void init() { ShardingSphereEventBus.getInstance().register(INSTANCE); new FinishedCheckJobExecutor().start(); new ScalingJobExecutor().start(); } /** * Start scaling job. * * @param event start scaling event. */ @Subscribe public void start(final StartScalingEvent event) { log.info("Start scaling job by {}", event); Optional<Long> jobId = scalingAPI.start(createJobConfig(event)); if (!jobId.isPresent()) { log.info("Switch rule configuration ruleCacheId = {} immediately.", event.getRuleCacheId()); ShardingSphereEventBus.getInstance().post(new SwitchRuleConfigurationEvent(event.getSchemaName(), event.getRuleCacheId())); } } private JobConfiguration createJobConfig(final StartScalingEvent event) { JobConfiguration result = new JobConfiguration(); result.setRuleConfig(getRuleConfiguration(event)); result.setHandleConfig(new HandleConfiguration(new WorkflowConfiguration(event.getSchemaName(), event.getRuleCacheId()))); return result; } private RuleConfiguration getRuleConfiguration(final StartScalingEvent event) { RuleConfiguration result = new RuleConfiguration(); result.setSource(new ShardingSphereJDBCDataSourceConfiguration(event.getSourceDataSource(), event.getSourceRule()).wrap()); result.setTarget(new ShardingSphereJDBCDataSourceConfiguration(event.getTargetDataSource(), event.getTargetRule()).wrap()); return result; } }
ScalingJobExecutor 监听注册中心任务，收到通知后做对应的执行动作，相当于通过注册中心解耦了http请求接收和真正的执行处理
@Slf4j public final class ScalingJobExecutor extends AbstractScalingExecutor { private static final Pattern CONFIG_PATTERN = Pattern.compile(ScalingConstant.SCALING_ROOT + "/(\\d+)/config"); private static final Set<String> EXECUTING_JOBS = Sets.newConcurrentHashSet(); @Override public void start() { super.start(); log.info("Start scaling job executor."); watchGovernanceRepositoryConfiguration(); } private void watchGovernanceRepositoryConfiguration() { ScalingAPIFactory.getGovernanceRepositoryAPI().watch(ScalingConstant.SCALING_ROOT, event -> { Optional<JobConfigurationPOJO> jobConfigPOJOOptional = getJobConfigPOJO(event); if (!jobConfigPOJOOptional.isPresent()) { return; } JobConfigurationPOJO jobConfigPOJO = jobConfigPOJOOptional.get(); if (DataChangedEvent.Type.DELETED == event.getType() || jobConfigPOJO.isDisabled()) { EXECUTING_JOBS.remove(jobConfigPOJO.getJobName()); JobSchedulerCenter.stop(Long.parseLong(jobConfigPOJO.getJobName())); return; } switch (event.getType()) { case ADDED: case UPDATED: execute(jobConfigPOJO); break; default: break; } }); } private Optional<JobConfigurationPOJO> getJobConfigPOJO(final DataChangedEvent event) { try { if (CONFIG_PATTERN.matcher(event.getKey()).matches()) { log.info("{} job config: {} = {}", event.getType(), event.getKey(), event.getValue()); return Optional.of(YamlEngine.unmarshal(event.getValue(), JobConfigurationPOJO.class)); } // CHECKSTYLE:OFF } catch (final Exception ex) { // CHECKSTYLE:ON log.error("analyze job config pojo failed.", ex); } return Optional.empty(); } private void execute(final JobConfigurationPOJO jobConfigPOJO) { if (EXECUTING_JOBS.add(jobConfigPOJO.getJobName())) { new OneOffJobBootstrap(ScalingAPIFactory.getRegistryCenter(), new ScalingJob(), jobConfigPOJO.toJobConfiguration()).execute(); } } }
具体的扩展操作是分为几个步骤的，官网写的不错，转
准备阶段：在准备阶段，弹性伸缩模块会进行数据源连通性及权限的校验，同时进行存量数据的统计、日志位点的记录，最后根据数据量和用户设置的并行度，对任务进行分片。
存量数据迁移阶段：执行在准备阶段拆分好的存量数据迁移作业，存量迁移阶段采用 JDBC 查询的方式，直接从数据节点中读取数据，并使用新规则写入到新集群中。
增量数据同步阶段：由于存量数据迁移耗费的时间受到数据量和并行度等因素影响，此时需要对这段时间内业务新增的数据进行同步。 不同的数据库使用的技术细节不同，但总体上均为基于复制协议或 WAL 日志实现的变更数据捕获功能。
-
MySQL：订阅并解析 binlog
-
PostgreSQL：采用官方逻辑复制
这些捕获的增量数据，同样会由弹性伸缩模块根据新规则写入到新数据节点中。当增量数据基本同步完成时（由于业务系统未停止，增量数据是不断的），则进入规则切换阶段。
规则切换阶段：在此阶段，可能存在一定时间的业务只读窗口期，通过设置数据库只读或ShardingSphere的熔断机制，让旧数据节点中的数据短暂静态，确保增量同步已完全完成。这个窗口期时间短则数秒，长则数分钟，取决于数据量和用户是否需要对数据进行强校验。 确认完成后，Apache ShardingSphere 可通过配置中心修改配置，将业务导向新规则的集群，弹性伸缩完成。
先不论其他，先来看下MySql Binlog同步相关代码
MySQLClient 这个类整体就是启动一个Netty服务，支持与MYSQL做协议交互，伪装从节点做binlog同步，dump等。。。
@RequiredArgsConstructor @Slf4j public final class MySQLClient { private final ConnectInfo connectInfo; private EventLoopGroup eventLoopGroup; private Channel channel; private Promise<Object> responseCallback; private final ArrayBlockingQueue<AbstractBinlogEvent> blockingEventQueue = new ArrayBlockingQueue<>(10000); private ServerInfo serverInfo; /** * Connect to MySQL. */ public synchronized void connect() { eventLoopGroup = new NioEventLoopGroup(1); responseCallback = new DefaultPromise<>(eventLoopGroup.next()); channel = new Bootstrap() .group(eventLoopGroup) .channel(NioSocketChannel.class) .option(ChannelOption.AUTO_READ, true) .handler(new ChannelInitializer<SocketChannel>() { @Override protected void initChannel(final SocketChannel socketChannel) { socketChannel.pipeline().addLast(new PacketCodec(new MySQLPacketCodecEngine())); socketChannel.pipeline().addLast(new MySQLNegotiatePackageDecoder()); socketChannel.pipeline().addLast(new MySQLCommandPacketDecoder()); socketChannel.pipeline().addLast(new MySQLNegotiateHandler(connectInfo.getUsername(), connectInfo.getPassword(), responseCallback)); socketChannel.pipeline().addLast(new MySQLCommandResponseHandler()); } }).connect(connectInfo.getHost(), connectInfo.getPort()).channel(); serverInfo = waitExpectedResponse(ServerInfo.class); } /** * Execute command. * * @param queryString query string * @return true if execute successfully, otherwise false */ public synchronized boolean execute(final String queryString) { responseCallback = new DefaultPromise<>(eventLoopGroup.next()); MySQLComQueryPacket comQueryPacket = new MySQLComQueryPacket(queryString); channel.writeAndFlush(comQueryPacket); return null != waitExpectedResponse(MySQLOKPacket.class); } /** * Execute update. * * @param queryString query string * @return affected rows */ public synchronized int executeUpdate(final String queryString) { responseCallback = new DefaultPromise<>(eventLoopGroup.next()); MySQLComQueryPacket comQueryPacket = new MySQLComQueryPacket(queryString); channel.writeAndFlush(comQueryPacket); return (int) Objects.requireNonNull(waitExpectedResponse(MySQLOKPacket.class)).getAffectedRows(); } /** * Execute query. * * @param queryString query string * @return result set */ public synchronized InternalResultSet executeQuery(final String queryString) { responseCallback = new DefaultPromise<>(eventLoopGroup.next()); MySQLComQueryPacket comQueryPacket = new MySQLComQueryPacket(queryString); channel.writeAndFlush(comQueryPacket); return waitExpectedResponse(InternalResultSet.class); } /** * Start dump binlog. * * @param binlogFileName binlog file name * @param binlogPosition binlog position */ public synchronized void subscribe(final String binlogFileName, final long binlogPosition) { initDumpConnectSession(); registerSlave(); dumpBinlog(binlogFileName, binlogPosition, queryChecksumLength()); } private void initDumpConnectSession() { if (serverInfo.getServerVersion().greaterThanOrEqualTo(5, 6, 0)) { execute("SET @MASTER_BINLOG_CHECKSUM= @@GLOBAL.BINLOG_CHECKSUM"); } } private void registerSlave() { responseCallback = new DefaultPromise<>(eventLoopGroup.next()); InetSocketAddress localAddress = (InetSocketAddress) channel.localAddress(); MySQLComRegisterSlaveCommandPacket packet = new MySQLComRegisterSlaveCommandPacket( connectInfo.getServerId(), localAddress.getHostName(), connectInfo.getUsername(), connectInfo.getPassword(), localAddress.getPort()); channel.writeAndFlush(packet); waitExpectedResponse(MySQLOKPacket.class); } private int queryChecksumLength() { if (!serverInfo.getServerVersion().greaterThanOrEqualTo(5, 6, 0)) { return 0; } InternalResultSet resultSet = executeQuery("SELECT @@GLOBAL.BINLOG_CHECKSUM"); String checksumType = resultSet.getFieldValues().get(0).getData().iterator().next().toString(); switch (checksumType) { case "None": return 0; case "CRC32": return 4; default: throw new UnsupportedOperationException(checksumType); } } private void dumpBinlog(final String binlogFileName, final long binlogPosition, final int checksumLength) { responseCallback = null; channel.pipeline().remove(MySQLCommandPacketDecoder.class); channel.pipeline().remove(MySQLCommandResponseHandler.class); channel.pipeline().addLast(new MySQLBinlogEventPacketDecoder(checksumLength)); channel.pipeline().addLast(new MySQLBinlogEventHandler()); channel.writeAndFlush(new MySQLComBinlogDumpCommandPacket((int) binlogPosition, connectInfo.getServerId(), binlogFileName)); } /** * Poll binlog event. * * @return binlog event */ public synchronized AbstractBinlogEvent poll() { try { return blockingEventQueue.poll(100, TimeUnit.MILLISECONDS); } catch (final InterruptedException ignored) { return null; } } @SuppressWarnings("unchecked") private <T> T waitExpectedResponse(final Class<T> type) { try { Object response = responseCallback.get(); if (null == response) { return null; } if (type.equals(response.getClass())) { return (T) response; } if (response instanceof MySQLErrPacket) { throw new RuntimeException(((MySQLErrPacket) response).getErrorMessage()); } throw new RuntimeException("unexpected response type"); } catch (final InterruptedException | ExecutionException ex) { throw new RuntimeException(ex); } } private final class MySQLCommandResponseHandler extends ChannelInboundHandlerAdapter { @Override public void channelRead(final ChannelHandlerContext ctx, final Object msg) { if (null != responseCallback) { responseCallback.setSuccess(msg); } } @Override public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) { if (null != responseCallback) { responseCallback.setFailure(cause); log.error("protocol resolution error", cause); } } } private final class MySQLBinlogEventHandler extends ChannelInboundHandlerAdapter { private AbstractBinlogEvent lastBinlogEvent; @Override public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception { if (msg instanceof AbstractBinlogEvent) { lastBinlogEvent = (AbstractBinlogEvent) msg; blockingEventQueue.put(lastBinlogEvent); } } @Override public void channelInactive(final ChannelHandlerContext ctx) { log.warn("channel inactive"); reconnect(); } @Override public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) { log.error("protocol resolution error", cause); reconnect(); } private void reconnect() { log.info("reconnect mysql client."); closeOldChannel(); connect(); subscribe(lastBinlogEvent.getFileName(), lastBinlogEvent.getPosition()); } private void closeOldChannel() { try { channel.closeFuture().sync(); } catch (final InterruptedException ignored) { } } } }
