dolphinscheduler 源码解析-MasterSchedulerService

文章目录

• dolphinscheduler 源码解析-MasterSchedulerService
• • 类定义
  • 类属性
  • 初始化方法

类定义

@Service
public class MasterSchedulerService extends Thread 

可以看出该类继承了线程基类，那该类就可以在线程池内执行。

类属性

    /**
     * logger of MasterSchedulerService
     */
    private static final Logger logger = LoggerFactory.getLogger(MasterSchedulerService.class);

    /**
     * dolphinscheduler database interface
     */
    @Autowired
    private ProcessService processService;

    /**
     * zookeeper master client
     */
    @Autowired
    private MasterRegistryClient masterRegistryClient;

    /**
     * master config
     */
    @Autowired
    private MasterConfig masterConfig;

    /**
     * alert manager
     */
    @Autowired
    private ProcessAlertManager processAlertManager;

    /**
     *  netty remoting client
     */
    private NettyRemotingClient nettyRemotingClient;

    /**
     * master exec service
     */
    private ThreadPoolExecutor masterExecService;

可以看出它有一个ProcessService这个属性集成了很多mappers类，提供数据dao服务。还有一个ProcessAlertManager 告警的管理器，另外也有netty的客户端和一个线程池。

初始化方法

@PostConstruct
public void init() {
    this.masterExecService = (ThreadPoolExecutor)ThreadUtils.newDaemonFixedThreadExecutor("Master-Exec-Thread", masterConfig.getMasterExecThreads());
    NettyClientConfig clientConfig = new NettyClientConfig();
    this.nettyRemotingClient = new NettyRemotingClient(clientConfig);
}

对线程池进行赋值，并且创建一个netty的客户端。

既然是线程类，就必须有run方法，我们查看一下run方法

    /**
     * run of MasterSchedulerService
     */
    @Override
    public void run() {
        logger.info("master scheduler started");
        while (Stopper.isRunning()) {
            try {
                boolean runCheckFlag = OSUtils.checkResource(masterConfig.getMasterMaxCpuloadAvg(), masterConfig.getMasterReservedMemory());
                if (!runCheckFlag) {
                    Thread.sleep(Constants.SLEEP_TIME_MILLIS);
                    continue;
                }
                scheduleProcess();
            } catch (Exception e) {
                logger.error("master scheduler thread error", e);
            }
        }
    }

该run方法会先检查一下资源，看是否有空闲资源，如果没有就让线程睡眠一会儿然后重新检查资源，当有了足够的资源就开始执行scheduleProcess方法

我们向下追踪scheduleProcess方法

    private void scheduleProcess() throws Exception {

        try {
            masterRegistryClient.blockAcquireMutex();

            int activeCount = masterExecService.getActiveCount();
            // make sure to scan and delete command  table in one transaction
            Command command = processService.findOneCommand();
            if (command != null) {
                logger.info("find one command: id: {}, type: {}", command.getId(),command.getCommandType());

                try {

                    ProcessInstance processInstance = processService.handleCommand(logger,
                            getLocalAddress(),
                            this.masterConfig.getMasterExecThreads() - activeCount, command);
                    if (processInstance != null) {
                        logger.info("start master exec thread , split DAG ...");
                        masterExecService.execute(
                                new MasterExecThread(
                                        processInstance
                                        , processService
                                        , nettyRemotingClient
                                        , processAlertManager
                                        , masterConfig));
                    }
                } catch (Exception e) {
                    logger.error("scan command error ", e);
                    processService.moveToErrorCommand(command, e.toString());
                }
            } else {
                //indicate that no command ,sleep for 1s
                Thread.sleep(Constants.SLEEP_TIME_MILLIS);
            }
        } finally {
            masterRegistryClient.releaseLock();
        }
    }

首先获取一个master的分布式锁

查看master的executor线程池中有多少active状态的线程。

从数据库中拿到一个command命令

然后构造一个该命令对应的实体类ProcessInstance

然后在该类的线程池内执行MasterExecThread线程【点击打开MasterExecThread】。

标签：MasterSchedulerService,dolphinscheduler,private,源码,command,master,线程,logger
来源： https://blog.csdn.net/sinat_35045195/article/details/119222093