聊聊PowerJob Server的高可用

本文主要是介绍聊聊PowerJob Server的高可用，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

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本文主要研究一下PowerJob Server的高可用

PowerJobSpringWorker

tech/powerjob/worker/PowerJobSpringWorker.java

public class PowerJobSpringWorker implements ApplicationContextAware, InitializingBean, DisposableBean {/*** 组合优于继承，持有 PowerJobWorker，内部重新设置 ProcessorFactory 更优雅*/private PowerJobWorker powerJobWorker;private final PowerJobWorkerConfig config;public PowerJobSpringWorker(PowerJobWorkerConfig config) {this.config = config;}@Overridepublic void afterPropertiesSet() throws Exception {powerJobWorker = new PowerJobWorker(config);powerJobWorker.init();}@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException {BuiltInSpringProcessorFactory springProcessorFactory = new BuiltInSpringProcessorFactory(applicationContext);BuildInSpringMethodProcessorFactory springMethodProcessorFactory = new BuildInSpringMethodProcessorFactory(applicationContext);// append BuiltInSpringProcessorFactoryList<ProcessorFactory> processorFactories = Lists.newArrayList(Optional.ofNullable(config.getProcessorFactoryList()).orElse(Collections.emptyList()));processorFactories.add(springProcessorFactory);processorFactories.add(springMethodProcessorFactory);config.setProcessorFactoryList(processorFactories);}@Overridepublic void destroy() throws Exception {powerJobWorker.destroy();}
}

PowerJobSpringWorker实现了InitializingBean接口，其afterPropertiesSet会创建powerJobWorker，然后执行其init方法

PowerJobWorker.init

tech/powerjob/worker/PowerJobWorker.java

    public void init() throws Exception {if (!initialized.compareAndSet(false, true)) {log.warn("[PowerJobWorker] please do not repeat the initialization");return;}Stopwatch stopwatch = Stopwatch.createStarted();log.info("[PowerJobWorker] start to initialize PowerJobWorker...");PowerJobWorkerConfig config = workerRuntime.getWorkerConfig();CommonUtils.requireNonNull(config, "can't find PowerJobWorkerConfig, please set PowerJobWorkerConfig first");ServerDiscoveryService serverDiscoveryService = new PowerJobServerDiscoveryService(config);workerRuntime.setServerDiscoveryService(serverDiscoveryService);try {PowerBannerPrinter.print();// 校验 appNameWorkerAppInfo appInfo = serverDiscoveryService.assertApp();workerRuntime.setAppInfo(appInfo);// 初始化网络数据，区别对待上报地址和本机绑定地址（对外统一使用上报地址）String localBindIp = NetUtils.getLocalHost();int localBindPort = config.getPort();String externalIp = PropertyUtils.readProperty(PowerJobDKey.NT_EXTERNAL_ADDRESS, localBindIp);String externalPort = PropertyUtils.readProperty(PowerJobDKey.NT_EXTERNAL_PORT, String.valueOf(localBindPort));log.info("[PowerJobWorker] [ADDRESS_INFO] localBindIp: {}, localBindPort: {}; externalIp: {}, externalPort: {}", localBindIp, localBindPort, externalIp, externalPort);workerRuntime.setWorkerAddress(Address.toFullAddress(externalIp, Integer.parseInt(externalPort)));// 初始化 线程池final ExecutorManager executorManager = new ExecutorManager(workerRuntime.getWorkerConfig());workerRuntime.setExecutorManager(executorManager);// 初始化 ProcessorLoaderProcessorLoader processorLoader = buildProcessorLoader(workerRuntime);workerRuntime.setProcessorLoader(processorLoader);// 初始化 actorTaskTrackerActor taskTrackerActor = new TaskTrackerActor(workerRuntime);ProcessorTrackerActor processorTrackerActor = new ProcessorTrackerActor(workerRuntime);WorkerActor workerActor = new WorkerActor(workerRuntime, taskTrackerActor);// 初始化通讯引擎EngineConfig engineConfig = new EngineConfig().setType(config.getProtocol().name()).setServerType(ServerType.WORKER).setBindAddress(new Address().setHost(localBindIp).setPort(localBindPort)).setActorList(Lists.newArrayList(taskTrackerActor, processorTrackerActor, workerActor));EngineOutput engineOutput = remoteEngine.start(engineConfig);workerRuntime.setTransporter(engineOutput.getTransporter());// 连接 serverserverDiscoveryService.timingCheck(workerRuntime.getExecutorManager().getCoreExecutor());log.info("[PowerJobWorker] PowerJobRemoteEngine initialized successfully.");// 初始化日志系统OmsLogHandler omsLogHandler = new OmsLogHandler(workerRuntime.getWorkerAddress(), workerRuntime.getTransporter(), serverDiscoveryService);workerRuntime.setOmsLogHandler(omsLogHandler);// 初始化存储TaskPersistenceService taskPersistenceService = new TaskPersistenceService(workerRuntime.getWorkerConfig().getStoreStrategy());taskPersistenceService.init();workerRuntime.setTaskPersistenceService(taskPersistenceService);log.info("[PowerJobWorker] local storage initialized successfully.");// 初始化定时任务workerRuntime.getExecutorManager().getCoreExecutor().scheduleAtFixedRate(new WorkerHealthReporter(workerRuntime), 0, config.getHealthReportInterval(), TimeUnit.SECONDS);workerRuntime.getExecutorManager().getCoreExecutor().scheduleWithFixedDelay(omsLogHandler.logSubmitter, 0, 5, TimeUnit.SECONDS);log.info("[PowerJobWorker] PowerJobWorker initialized successfully, using time: {}, congratulations!", stopwatch);}catch (Exception e) {log.error("[PowerJobWorker] initialize PowerJobWorker failed, using {}.", stopwatch, e);throw e;}}

PowerJobWorker的init方法会执行serverDiscoveryService.timingCheck(workerRuntime.getExecutorManager().getCoreExecutor())调度timingCheck

timingCheck

tech/powerjob/worker/background/discovery/PowerJobServerDiscoveryService.java

    public void timingCheck(ScheduledExecutorService timingPool) {this.currentServerAddress = discovery();if (StringUtils.isEmpty(this.currentServerAddress) && !config.isAllowLazyConnectServer()) {throw new PowerJobException("can't find any available server, this worker has been quarantined.");}// 这里必须保证成功timingPool.scheduleAtFixedRate(() -> {try {this.currentServerAddress = discovery();} catch (Exception e) {log.error("[PowerDiscovery] fail to discovery server!", e);}}, 10, 10, TimeUnit.SECONDS);}

PowerJobServerDiscoveryService的timingCheck会使用timingPool定时每隔10s调度执行discovery()来更新当前worker的server地址

discovery

    private String discovery() {// 只有允许延迟加载模式下，appId 才可能为空。每次服务发现前，都重新尝试获取 appInfo。由于是懒加载链路，此处完全忽略异常if (appInfo.getAppId() == null || appInfo.getAppId() < 0) {try {assertApp0();} catch (Exception e) {log.warn("[PowerDiscovery] assertAppName in discovery stage failed, msg: {}", e.getMessage());return null;}}if (ip2Address.isEmpty()) {config.getServerAddress().forEach(x -> ip2Address.put(x.split(":")[0], x));}String result = null;// 先对当前机器发起请求String currentServer = currentServerAddress;if (!StringUtils.isEmpty(currentServer)) {String ip = currentServer.split(":")[0];// 直接请求当前Server的HTTP服务，可以少一次网络开销，减轻Server负担String firstServerAddress = ip2Address.get(ip);if (firstServerAddress != null) {result = acquire(firstServerAddress);}}for (String httpServerAddress : config.getServerAddress()) {if (StringUtils.isEmpty(result)) {result = acquire(httpServerAddress);}else {break;}}if (StringUtils.isEmpty(result)) {log.warn("[PowerDiscovery] can't find any available server, this worker has been quarantined.");// 在 Server 高可用的前提下，连续失败多次，说明该节点与外界失联，Server已经将秒级任务转移到其他Worker，需要杀死本地的任务if (FAILED_COUNT++ > MAX_FAILED_COUNT) {log.warn("[PowerDiscovery] can't find any available server for 3 consecutive times, It's time to kill all frequent job in this worker.");List<Long> frequentInstanceIds = HeavyTaskTrackerManager.getAllFrequentTaskTrackerKeys();if (!CollectionUtils.isEmpty(frequentInstanceIds)) {frequentInstanceIds.forEach(instanceId -> {HeavyTaskTracker taskTracker = HeavyTaskTrackerManager.removeTaskTracker(instanceId);taskTracker.destroy();log.warn("[PowerDiscovery] kill frequent instance(instanceId={}) due to can't find any available server.", instanceId);});}FAILED_COUNT = 0;}return null;} else {// 重置失败次数FAILED_COUNT = 0;log.debug("[PowerDiscovery] current server is {}.", result);return result;}}

discovery方法就是定时遍历配置的serverAddress地址列表，调用server端的acquire方法来获取可用的server

acquireServer

tech/powerjob/server/web/controller/ServerController.java

    @GetMapping("/acquire")public ResultDTO<String> acquireServer(ServerDiscoveryRequest request) {return ResultDTO.success(serverElectionService.elect(request));}

ServerController提供了acquire接口，它执行的是serverElectionService.elect(request)

elect

tech/powerjob/server/remote/server/election/ServerElectionService.java

    public String elect(ServerDiscoveryRequest request) {if (!accurate()) {final String currentServer = request.getCurrentServer();// 如果是本机，就不需要查数据库那么复杂的操作了，直接返回成功Optional<ProtocolInfo> localProtocolInfoOpt = Optional.ofNullable(transportService.allProtocols().get(request.getProtocol()));if (localProtocolInfoOpt.isPresent()) {if (localProtocolInfoOpt.get().getExternalAddress().equals(currentServer) || localProtocolInfoOpt.get().getAddress().equals(currentServer)) {log.info("[ServerElection] this server[{}] is worker[appId={}]'s current server, skip check", currentServer, request.getAppId());return currentServer;}}}return getServer0(request);}

ServerElectionService的elect方法主要是执行getServer0

getServer0

    private String getServer0(ServerDiscoveryRequest discoveryRequest) {final Long appId = discoveryRequest.getAppId();final String protocol = discoveryRequest.getProtocol();Set<String> downServerCache = Sets.newHashSet();for (int i = 0; i < RETRY_TIMES; i++) {// 无锁获取当前数据库中的ServerOptional<AppInfoDO> appInfoOpt = appInfoRepository.findById(appId);if (!appInfoOpt.isPresent()) {throw new PowerJobException(appId + " is not registered!");}String appName = appInfoOpt.get().getAppName();String originServer = appInfoOpt.get().getCurrentServer();String activeAddress = activeAddress(originServer, downServerCache, protocol);if (StringUtils.isNotEmpty(activeAddress)) {return activeAddress;}// 无可用Server，重新进行Server选举，需要加锁String lockName = String.format(SERVER_ELECT_LOCK, appId);boolean lockStatus = lockService.tryLock(lockName, 30000);if (!lockStatus) {try {Thread.sleep(500);}catch (Exception ignore) {}continue;}try {// 可能上一台机器已经完成了Server选举，需要再次判断AppInfoDO appInfo = appInfoRepository.findById(appId).orElseThrow(() -> new RuntimeException("impossible, unless we just lost our database."));String address = activeAddress(appInfo.getCurrentServer(), downServerCache, protocol);if (StringUtils.isNotEmpty(address)) {return address;}// 篡位，如果本机存在协议，则作为Server调度该 workerfinal ProtocolInfo targetProtocolInfo = transportService.allProtocols().get(protocol);if (targetProtocolInfo != null) {// 注意，写入 AppInfoDO#currentServer 的永远是 default 的绑定地址，仅在返回的时候特殊处理为协议地址appInfo.setCurrentServer(transportService.defaultProtocol().getAddress());appInfo.setGmtModified(new Date());appInfoRepository.saveAndFlush(appInfo);log.info("[ServerElection] this server({}) become the new server for app(appId={}).", appInfo.getCurrentServer(), appId);return targetProtocolInfo.getExternalAddress();}}catch (Exception e) {log.error("[ServerElection] write new server to db failed for app {}.", appName, e);} finally {lockService.unlock(lockName);}}throw new PowerJobException("server elect failed for app " + appId);}

getServer0方法会重试10次，它先针对discoveryRequest指定的currentServer进行activeAddress，成功则返回，没有可用server则加锁进行重新分配，这里优先本机判断

activeAddress

    private String activeAddress(String serverAddress, Set<String> downServerCache, String protocol) {if (downServerCache.contains(serverAddress)) {return null;}if (StringUtils.isEmpty(serverAddress)) {return null;}Ping ping = new Ping();ping.setCurrentTime(System.currentTimeMillis());URL targetUrl = ServerURLFactory.ping2Friend(serverAddress);try {AskResponse response = transportService.ask(Protocol.HTTP.name(), targetUrl, ping, AskResponse.class).toCompletableFuture().get(PING_TIMEOUT_MS, TimeUnit.MILLISECONDS);if (response.isSuccess()) {// 检测通过的是远程 server 的暴露地址，需要返回 worker 需要的协议地址final JSONObject protocolInfo = JsonUtils.parseObject(response.getData(), JSONObject.class).getJSONObject(protocol);if (protocolInfo != null) {downServerCache.remove(serverAddress);ProtocolInfo remoteProtocol = protocolInfo.toJavaObject(ProtocolInfo.class);log.info("[ServerElection] server[{}] is active, it will be the master, final protocol={}", serverAddress, remoteProtocol);// 4.3.3 升级 4.3.4 过程中，未升级的 server 还不存在 externalAddress，需要使用 address 兼容return Optional.ofNullable(remoteProtocol.getExternalAddress()).orElse(remoteProtocol.getAddress());} else {log.warn("[ServerElection] server[{}] is active but don't have target protocol", serverAddress);}}} catch (TimeoutException te) {log.warn("[ServerElection] server[{}] was down due to ping timeout!", serverAddress);} catch (Exception e) {log.warn("[ServerElection] server[{}] was down with unknown case!", serverAddress, e);}downServerCache.add(serverAddress);return null;}

activeAddress方法主要是对目标server发起ping请求，超时时间为1s，若目标server挂了，则抛出TimeoutException，将目标server加入到downServerCache中；若目标server响应成功，则从downServerCache中移除

小结

PowerJob的worker在初始化的时候会启动一个定时任务，每隔10s调度执行discovery()来更新当前worker的server地址；discovery方法就是定时遍历配置的serverAddress地址列表，调用server端的acquire方法来获取可用的server；ServerController提供了acquire接口，它执行的是serverElectionService.elect(request)，ServerElectionService的elect方法主要是执行getServer0，getServer0方法会重试10次，它先针对discoveryRequest指定的currentServer进行activeAddress，成功则返回，没有可用server则加锁进行重新分配，这里优先本机判断。activeAddress方法主要是对目标server发起ping请求，超时时间为1s，若目标server挂了，则抛出TimeoutException，将目标server加入到downServerCache中；若目标server响应成功，则从downServerCache中移除。

worker定时任务 --> 轮询serverAddress请求acquire --> server端判断目标server的ping是否成功，不成功则加锁优先使用本机作为替代server。

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