聊聊Powerjob的单机线程并发度

@Data
public class InstanceInfo implements Serializable {

    /**
     * 基础信息
     */
    private Long jobId;
    private Long instanceId;
    private Long wfInstanceId;

    /**
     * 任务执行处理器信息
     */
    // 任务执行类型，单机、广播、MR
    private String executeType;
    // 处理器类型（JavaBean、Jar、脚本等）
    private String processorType;
    // 处理器信息
    private String processorInfo;
    // 定时类型
    private int timeExpressionType;

    /**
     * 超时时间
     */
    // 整个任务的总体超时时间
    private long instanceTimeoutMS;

    /**
     * 任务运行参数
     */
    // 任务级别的参数，相当于类的static变量
    private String jobParams;
    // 实例级别的参数，相当于类的普通变量
    private String instanceParams;


    // 每台机器的处理线程数上限
    private int threadConcurrency;
    // 子任务重试次数（任务本身的重试机制由server控制）
    private int taskRetryNum;

    private String logConfig;
}

/**
     * 定时扫描数据库中的task（出于内存占用量考虑，每次最多获取100个），并将需要执行的任务派发出去
     */
    protected class Dispatcher implements Runnable {

        // 数据库查询限制，每次最多查询几个任务
        private static final int DB_QUERY_LIMIT = 100;

        @Override
        public void run() {

            if (finished.get()) {
                return;
            }

            Stopwatch stopwatch = Stopwatch.createStarted();

            // 1. 获取可以派发任务的 ProcessorTracker
            List<String> availablePtIps = ptStatusHolder.getAvailableProcessorTrackers();

            // 2. 没有可用 ProcessorTracker，本次不派发
            if (availablePtIps.isEmpty()) {
                log.debug("[TaskTracker-{}] no available ProcessorTracker now.", instanceId);
                return;
            }

            // 3. 避免大查询，分批派发任务
            long currentDispatchNum = 0;
            long maxDispatchNum = availablePtIps.size() * instanceInfo.getThreadConcurrency() * 2L;
            AtomicInteger index = new AtomicInteger(0);

            // 4. 循环查询数据库，获取需要派发的任务
            while (maxDispatchNum > currentDispatchNum) {

                int dbQueryLimit = Math.min(DB_QUERY_LIMIT, (int) maxDispatchNum);
                List<TaskDO> needDispatchTasks = taskPersistenceService.getTaskByStatus(instanceId, TaskStatus.WAITING_DISPATCH, dbQueryLimit);
                currentDispatchNum += needDispatchTasks.size();

                needDispatchTasks.forEach(task -> {
                    // 获取 ProcessorTracker 地址，如果 Task 中自带了 Address，则使用该 Address
                    String ptAddress = task.getAddress();
                    if (StringUtils.isEmpty(ptAddress) || RemoteConstant.EMPTY_ADDRESS.equals(ptAddress)) {
                        ptAddress = availablePtIps.get(index.getAndIncrement() % availablePtIps.size());
                    }
                    dispatchTask(task, ptAddress);
                });

                // 数量不足 或 查询失败，则终止循环
                if (needDispatchTasks.size() < dbQueryLimit) {
                    break;
                }
            }

            log.debug("[TaskTracker-{}] dispatched {} tasks,using time {}.", instanceId, currentDispatchNum, stopwatch.stop());
        }
    }

private int calThreadPoolSize() {
        ExecuteType executeType = ExecuteType.valueOf(instanceInfo.getExecuteType());
        ProcessorType processorType = ProcessorType.valueOf(instanceInfo.getProcessorType());

        // 脚本类自带线程池，不过为了少一点逻辑判断，还是象征性分配一个线程
        if (processorType == ProcessorType.PYTHON || processorType == ProcessorType.SHELL) {
            return 1;
        }

        if (executeType == ExecuteType.MAP_REDUCE || executeType == ExecuteType.MAP) {
            return instanceInfo.getThreadConcurrency();
        }
        if (TimeExpressionType.FREQUENT_TYPES.contains(instanceInfo.getTimeExpressionType())) {
            return instanceInfo.getThreadConcurrency();
        }
        return 2;
    }

private static final int THREAD_POOL_QUEUE_MAX_SIZE = 128;

    private void initThreadPool() {

        int poolSize = calThreadPoolSize();
        // 待执行队列，为了防止对内存造成较大压力，内存队列不能太大
        BlockingQueue<Runnable> queue = new ArrayBlockingQueue<>(THREAD_POOL_QUEUE_MAX_SIZE);
        // 自定义线程池中线程名称 (PowerJob Processor Pool -> PPP)
        ThreadFactory threadFactory = new ThreadFactoryBuilder().setNameFormat("PPP-%d").build();
        // 拒绝策略：直接抛出异常
        RejectedExecutionHandler rejectionHandler = new ThreadPoolExecutor.AbortPolicy();

        threadPool = new ThreadPoolExecutor(poolSize, poolSize, 60L, TimeUnit.SECONDS, queue, threadFactory, rejectionHandler);

        // 当没有任务执行时，允许销毁核心线程（即线程池最终存活线程个数可能为0）
        threadPool.allowCoreThreadTimeOut(true);
    }

public void submitTask(TaskDO newTask) {

        // 一旦 ProcessorTracker 出现异常，所有提交到此处的任务直接返回失败，防止形成死锁
        // 死锁分析：TT创建PT，PT创建失败，无法定期汇报心跳，TT长时间未收到PT心跳，认为PT宕机（确实宕机了），无法选择可用的PT再次派发任务，死锁形成，GG斯密达 T_T
        if (lethal) {
            ProcessorReportTaskStatusReq report = new ProcessorReportTaskStatusReq()
                    .setInstanceId(instanceId)
                    .setSubInstanceId(newTask.getSubInstanceId())
                    .setTaskId(newTask.getTaskId())
                    .setStatus(TaskStatus.WORKER_PROCESS_FAILED.getValue())
                    .setResult(lethalReason)
                    .setReportTime(System.currentTimeMillis());

            TransportUtils.ptReportTask(report, taskTrackerAddress, workerRuntime);
            return;
        }

        boolean success = false;
        // 1. 设置值并提交执行
        newTask.setInstanceId(instanceInfo.getInstanceId());
        newTask.setAddress(taskTrackerAddress);

        HeavyProcessorRunnable heavyProcessorRunnable = new HeavyProcessorRunnable(instanceInfo, taskTrackerAddress, newTask, processorBean, omsLogger, statusReportRetryQueue, workerRuntime);
        try {
            threadPool.submit(heavyProcessorRunnable);
            success = true;
        } catch (RejectedExecutionException ignore) {
            log.warn("[ProcessorTracker-{}] submit task(taskId={},taskName={}) to ThreadPool failed due to ThreadPool has too much task waiting to process, this task will dispatch to other ProcessorTracker.",
                    instanceId, newTask.getTaskId(), newTask.getTaskName());
        } catch (Exception e) {
            log.error("[ProcessorTracker-{}] submit task(taskId={},taskName={}) to ThreadPool failed.", instanceId, newTask.getTaskId(), newTask.getTaskName(), e);
        }

        // 2. 回复接收成功
        if (success) {
            ProcessorReportTaskStatusReq reportReq = new ProcessorReportTaskStatusReq();
            reportReq.setInstanceId(instanceId);
            reportReq.setSubInstanceId(newTask.getSubInstanceId());
            reportReq.setTaskId(newTask.getTaskId());
            reportReq.setStatus(TaskStatus.WORKER_RECEIVED.getValue());
            reportReq.setReportTime(System.currentTimeMillis());

            TransportUtils.ptReportTask(reportReq, taskTrackerAddress, workerRuntime);

            log.debug("[ProcessorTracker-{}] submit task(taskId={}, taskName={}) success, current queue size: {}.",
                    instanceId, newTask.getTaskId(), newTask.getTaskName(), threadPool.getQueue().size());
        }
    }

@Handler(path = WTT_HANDLER_REPORT_TASK_STATUS)
    public AskResponse onReceiveProcessorReportTaskStatusReq(ProcessorReportTaskStatusReq req) {

        int taskStatus = req.getStatus();
        // 只有重量级任务才会有两级任务状态上报的机制
        HeavyTaskTracker taskTracker = HeavyTaskTrackerManager.getTaskTracker(req.getInstanceId());

        // 手动停止 TaskTracker 的情况下会出现这种情况
        if (taskTracker == null) {
            log.warn("[TaskTrackerActor] receive ProcessorReportTaskStatusReq({}) but system can't find TaskTracker.", req);
            return null;
        }

        if (ProcessorReportTaskStatusReq.BROADCAST.equals(req.getCmd())) {
            taskTracker.broadcast(taskStatus == TaskStatus.WORKER_PROCESS_SUCCESS.getValue(), req.getSubInstanceId(), req.getTaskId(), req.getResult());
        }

        taskTracker.updateTaskStatus(req.getSubInstanceId(), req.getTaskId(), taskStatus, req.getReportTime(), req.getResult());

        // 更新工作流上下文
        taskTracker.updateAppendedWfContext(req.getAppendedWfContext());

        // 结束状态需要回复接受成功
        if (TaskStatus.FINISHED_STATUS.contains(taskStatus)) {
            return AskResponse.succeed(null);
        }

        return null;
    }

@Getter
@AllArgsConstructor
public enum TaskStatus {

    WAITING_DISPATCH(1, "等待调度器调度"),
    DISPATCH_SUCCESS_WORKER_UNCHECK(2, "调度成功（但不保证worker收到）"),
    WORKER_RECEIVED(3, "worker接收成功，但未开始执行"),
    WORKER_PROCESSING(4, "worker正在执行"),
    WORKER_PROCESS_FAILED(5, "worker执行失败"),
    WORKER_PROCESS_SUCCESS(6, "worker执行成功");

    public static final Set<Integer> FINISHED_STATUS = Sets.newHashSet(WORKER_PROCESS_FAILED.value, WORKER_PROCESS_SUCCESS.value);

    private final int value;
    private final String des;

    public static TaskStatus of(int v) {
        for (TaskStatus taskStatus : values()) {
            if (v == taskStatus.value) {
                return taskStatus;
            }
        }
        throw new IllegalArgumentException("no TaskStatus match the value of " + v);
    }
}

public void run() {
        // 切换线程上下文类加载器（否则用的是 Worker 类加载器，不存在容器类，在序列化/反序列化时会报 ClassNotFoundException）
        Thread.currentThread().setContextClassLoader(processorBean.getClassLoader());
        try {
            innerRun();
        } catch (InterruptedException ignore) {
            // ignore
        } catch (Throwable e) {
            reportStatus(TaskStatus.WORKER_PROCESS_FAILED, e.toString(), null, null);
            log.error("[ProcessorRunnable-{}] execute failed, please contact the author(@KFCFans) to fix the bug!", task.getInstanceId(), e);
        } finally {
            ThreadLocalStore.clear();
        }
    }

    public void innerRun() throws InterruptedException {

        final BasicProcessor processor = processorBean.getProcessor();

        String taskId = task.getTaskId();
        Long instanceId = task.getInstanceId();

        log.debug("[ProcessorRunnable-{}] start to run task(taskId={}&taskName={})", instanceId, taskId, task.getTaskName());
        ThreadLocalStore.setTask(task);
        ThreadLocalStore.setRuntimeMeta(workerRuntime);

        // 0. 构造任务上下文
        WorkflowContext workflowContext = constructWorkflowContext();
        TaskContext taskContext = constructTaskContext();
        taskContext.setWorkflowContext(workflowContext);
        // 1. 上报执行信息
        reportStatus(TaskStatus.WORKER_PROCESSING, null, null, null);

        ProcessResult processResult;
        ExecuteType executeType = ExecuteType.valueOf(instanceInfo.getExecuteType());

        // 2. 根任务 & 广播执行 特殊处理
        if (TaskConstant.ROOT_TASK_NAME.equals(task.getTaskName()) && executeType == ExecuteType.BROADCAST) {
            // 广播执行：先选本机执行 preProcess，完成后 TaskTracker 再为所有 Worker 生成子 Task
            handleBroadcastRootTask(instanceId, taskContext);
            return;
        }

        // 3. 最终任务特殊处理（一定和 TaskTracker 处于相同的机器）
        if (TaskConstant.LAST_TASK_NAME.equals(task.getTaskName())) {
            handleLastTask(taskId, instanceId, taskContext, executeType);
            return;
        }

        // 4. 正式提交运行
        try {
            processResult = processor.process(taskContext);
            if (processResult == null) {
                processResult = new ProcessResult(false, "ProcessResult can't be null");
            }
        } catch (Throwable e) {
            log.warn("[ProcessorRunnable-{}] task(id={},name={}) process failed.", instanceId, taskContext.getTaskId(), taskContext.getTaskName(), e);
            processResult = new ProcessResult(false, e.toString());
        }
        reportStatus(processResult.isSuccess() ? TaskStatus.WORKER_PROCESS_SUCCESS : TaskStatus.WORKER_PROCESS_FAILED, suit(processResult.getMsg()), null, workflowContext.getAppendedContextData());
    }