HeartBeatTask发送心跳的后台线程相关设计

1.封装后台线程BaseDaemonThread

public abstract class BaseDaemonThread extends Thread {

    protected BaseDaemonThread(Runnable runnable) {
        super(runnable);
        this.setDaemon(true);
    }

    protected BaseDaemonThread(String threadName) {
        super();
        this.setName(threadName);
        this.setDaemon(true);
    }

}

2.基于BaseDaemonThread设计基础BaseHeartBeatTask设计

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.dolphinscheduler.common.model;

import org.apache.dolphinscheduler.common.lifecycle.ServerLifeCycleManager;
import org.apache.dolphinscheduler.common.thread.BaseDaemonThread;

import lombok.extern.slf4j.Slf4j;

@Slf4j
public abstract class BaseHeartBeatTask<T> extends BaseDaemonThread {

    private final String threadName;
    private final long heartBeatInterval;

    protected boolean runningFlag;

    public BaseHeartBeatTask(String threadName, long heartBeatInterval) {
        super(threadName);
        this.threadName = threadName;
        this.heartBeatInterval = heartBeatInterval;
        this.runningFlag = true;
    }

    @Override
    public synchronized void start() {
        log.info("Starting {}...", threadName);
        super.start();
        log.info("Started {}, heartBeatInterval: {}...", threadName, heartBeatInterval);
    }

    @Override
    public void run() {
        while (runningFlag) {
            try {
                if (!ServerLifeCycleManager.isRunning()) {
                    log.info("The current server status is {}, will not write heartBeatInfo into registry",
                            ServerLifeCycleManager.getServerStatus());
                    continue;
                }
                T heartBeat = getHeartBeat();
                writeHeartBeat(heartBeat);
            } catch (Exception ex) {
                log.error("{} task execute failed", threadName, ex);
            } finally {
                try {
                    Thread.sleep(heartBeatInterval);
                } catch (InterruptedException e) {
                    handleInterruptException(e);
                }
            }
        }
    }

    public void shutdown() {
        runningFlag = false;
        log.warn("{} finished...", threadName);
    }

    private void handleInterruptException(InterruptedException ex) {
        log.warn("{} has been interrupted", threadName, ex);
        Thread.currentThread().interrupt();
    }

    public abstract T getHeartBeat();

    public abstract void writeHeartBeat(T heartBeat);
}

3.告警心跳Task的设计AlertHeartbeatTask

继承BaseHeartBeatTask，并用了父类BaseHeartBeatTask的方法

package org.apache.dolphinscheduler.alert.registry;

import org.apache.dolphinscheduler.alert.config.AlertConfig;
import org.apache.dolphinscheduler.common.model.AlertServerHeartBeat;
import org.apache.dolphinscheduler.common.model.BaseHeartBeatTask;
import org.apache.dolphinscheduler.common.utils.JSONUtils;
import org.apache.dolphinscheduler.common.utils.OSUtils;
import org.apache.dolphinscheduler.registry.api.RegistryClient;
import org.apache.dolphinscheduler.registry.api.enums.RegistryNodeType;

import lombok.extern.slf4j.Slf4j;

import org.springframework.stereotype.Component;

@Slf4j
@Component
public class AlertHeartbeatTask extends BaseHeartBeatTask<AlertServerHeartBeat> {

    private final AlertConfig alertConfig;
    private final Integer processId;
    private final RegistryClient registryClient;
    private final String heartBeatPath;
    private final long startupTime;

    public AlertHeartbeatTask(AlertConfig alertConfig,
                              RegistryClient registryClient) {
        super("AlertHeartbeatTask", alertConfig.getHeartbeatInterval().toMillis());
        this.startupTime = System.currentTimeMillis();
        this.alertConfig = alertConfig;
        this.registryClient = registryClient;
        this.heartBeatPath =
                RegistryNodeType.ALERT_SERVER.getRegistryPath() + "/" + alertConfig.getAlertServerAddress();
        this.processId = OSUtils.getProcessID();
    }

    @Override
    public AlertServerHeartBeat getHeartBeat() {
        return AlertServerHeartBeat.builder()
                .processId(processId)
                .startupTime(startupTime)
                .reportTime(System.currentTimeMillis())
                .cpuUsage(OSUtils.cpuUsagePercentage())
                .memoryUsage(OSUtils.memoryUsagePercentage())
                .availablePhysicalMemorySize(OSUtils.availablePhysicalMemorySize())
                .alertServerAddress(alertConfig.getAlertServerAddress())
                .build();
    }

    @Override
    public void writeHeartBeat(AlertServerHeartBeat heartBeat) {
        String heartBeatJson = JSONUtils.toJsonString(heartBeat);
        registryClient.persistEphemeral(heartBeatPath, heartBeatJson);
        log.debug("Success write master heartBeatInfo into registry, masterRegistryPath: {}, heartBeatInfo: {}",
                heartBeatPath, heartBeatJson);
    }
}

4.告警心跳客户端AlertRegistryClient的设计

@Slf4j
@Service
public class AlertRegistryClient implements AutoCloseable {

    @Autowired
    private RegistryClient registryClient;

    @Autowired
    private AlertConfig alertConfig;

    private AlertHeartbeatTask alertHeartbeatTask;

    public void start() {
        log.info("AlertRegistryClient starting...");
        registryClient.getLock(RegistryNodeType.ALERT_LOCK.getRegistryPath());
        alertHeartbeatTask = new AlertHeartbeatTask(alertConfig, registryClient);
        alertHeartbeatTask.start();
        // start heartbeat task
        log.info("AlertRegistryClient started...");
    }

    @Override
    public void close() {
        log.info("AlertRegistryClient closing...");
        alertHeartbeatTask.shutdown();
        registryClient.releaseLock(RegistryNodeType.ALERT_LOCK.getRegistryPath());
        log.info("AlertRegistryClient closed...");
    }
}

5.心跳任务开启的时机(应用启动类)

package org.apache.dolphinscheduler.alert;

import org.apache.dolphinscheduler.alert.plugin.AlertPluginManager;
import org.apache.dolphinscheduler.alert.registry.AlertRegistryClient;
import org.apache.dolphinscheduler.alert.rpc.AlertRpcServer;
import org.apache.dolphinscheduler.alert.service.AlertBootstrapService;
import org.apache.dolphinscheduler.common.constants.Constants;
import org.apache.dolphinscheduler.common.lifecycle.ServerLifeCycleManager;
import org.apache.dolphinscheduler.common.thread.ThreadUtils;

import javax.annotation.PreDestroy;

import lombok.extern.slf4j.Slf4j;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.context.event.ApplicationReadyEvent;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.event.EventListener;

@SpringBootApplication
@ComponentScan("org.apache.dolphinscheduler")
@Slf4j
public class AlertServer {

    @Autowired
    private AlertBootstrapService alertBootstrapService;
    @Autowired
    private AlertRpcServer alertRpcServer;
    @Autowired
    private AlertPluginManager alertPluginManager;
    @Autowired
    private AlertRegistryClient alertRegistryClient;

    public static void main(String[] args) {
        Thread.currentThread().setName(Constants.THREAD_NAME_ALERT_SERVER);
        new SpringApplicationBuilder(AlertServer.class).run(args);
    }

    @EventListener
    public void run(ApplicationReadyEvent readyEvent) {
        log.info("Alert server is staring ...");
        alertPluginManager.start(); // 插件管理者启动
        alertRegistryClient.start(); // 客户端注册启动
        alertBootstrapService.start();
        alertRpcServer.start();
        log.info("Alert server is started ...");
    }

    @PreDestroy
    public void close() {
        destroy("alert server destroy");
    }

    /**
     * gracefully stop
     *
     * @param cause stop cause
     */
    public void destroy(String cause) {

        try {
            // set stop signal is true
            // execute only once
            if (!ServerLifeCycleManager.toStopped()) {
                log.warn("AlterServer is already stopped");
                return;
            }
            log.info("Alert server is stopping, cause: {}", cause);
            try (
                    AlertRpcServer closedAlertRpcServer = alertRpcServer;
                    AlertBootstrapService closedAlertBootstrapService = alertBootstrapService;
                    AlertRegistryClient closedAlertRegistryClient = alertRegistryClient) {
                // close resource
            }
            // thread sleep 3 seconds for thread quietly stop
            ThreadUtils.sleep(Constants.SERVER_CLOSE_WAIT_TIME.toMillis());
            log.info("Alter server stopped, cause: {}", cause);
        } catch (Exception e) {
            log.error("Alert server stop failed, cause: {}", cause, e);
        }
    }
}