elastic-job源碼（1）- job自動裝配

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版本：3.1.0-SNAPSHOT git地址：https://github.com/apache/shardingsphere-elasticjob Maven 坐標

<dependency>
    <groupId>org.apache.shardingsphere.elasticjob</groupId>
    <artifactId>elasticjob-lite-spring-boot-starter</artifactId>
    <version>${latest.version}</version>
</dependency>

Spring.factories配置

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
  org.apache.shardingsphere.elasticjob.lite.spring.boot.job.ElasticJobLiteAutoConfiguration

在添加elasticjob-lite-spring-boot-starter啟動類的時候，會自動載入ElasticJobLiteAutoConfiguration，接下來看下ElasticJobLiteAutoConfiguration中所做的處理。 ElasticJobLiteAutoConfiguration.java

/**
 * ElasticJob-Lite auto configuration.
 */
@Configuration(proxyBeanMethods = false)
@AutoConfigureAfter(DataSourceAutoConfiguration.class)


/**
 * elastic job 開關
 * elasticjob.enabled.ture預設為true
 */
@ConditionalOnProperty(name = "elasticjob.enabled", havingValue = "true", matchIfMissing = true)


/**
 * 導入
 * ElasticJobRegistryCenterConfiguration.class 註冊中心配置
 * ElasticJobTracingConfiguration.class job事件追蹤配置
 * ElasticJobSnapshotServiceConfiguration.class 快照配置
 */
@Import({ElasticJobRegistryCenterConfiguration.class, ElasticJobTracingConfiguration.class, ElasticJobSnapshotServiceConfiguration.class})


/**
 * job相關配置信息
 */
@EnableConfigurationProperties(ElasticJobProperties.class)
public class ElasticJobLiteAutoConfiguration {
    
    @Configuration(proxyBeanMethods = false)
    /**
     * ElasticJobBootstrapConfiguration.class  創建job beans 註入spring容器
     * ScheduleJobBootstrapStartupRunner.class  執行類型為ScheduleJobBootstrap.class 的job開始運行
     */
    @Import({ElasticJobBootstrapConfiguration.class, ScheduleJobBootstrapStartupRunner.class})
    protected static class ElasticJobConfiguration {
    }
}

Elastic-job 是利用zookeeper 實現分散式job的功能，所以在自動裝配的時候，需要有zookeeper註冊中心的配置。自動裝配主要做了4件事事 1.配置zookeeper 客戶端信息，啟動連接zookeeper. 2.配置事件追蹤資料庫，用於保存job運行記錄 3.解析所有job配置文件，將所有job的bean放置在spring 單例bean中 4.識別job類型，在zookeeper節點上處理job節點數據，運行定時任務job. 第一件事：配置zookeeper 客戶端信息，啟動連接zookeeper. ZookeeperRegistryCenter.class

public void init() {
    log.debug("Elastic job: zookeeper registry center init, server lists is: {}.", zkConfig.getServerLists());
    CuratorFrameworkFactory.Builder builder = CuratorFrameworkFactory.builder()
            //設置zookeeper 伺服器地址
            .connectString(zkConfig.getServerLists())
            //設置重試機制
            .retryPolicy(new ExponentialBackoffRetry(zkConfig.getBaseSleepTimeMilliseconds(), zkConfig.getMaxRetries(), zkConfig.getMaxSleepTimeMilliseconds()))
            //設置命名空間，zookeeper節點名稱
            .namespace(zkConfig.getNamespace());
    //設置session超時時間
    if (0 != zkConfig.getSessionTimeoutMilliseconds()) {
        builder.sessionTimeoutMs(zkConfig.getSessionTimeoutMilliseconds());
    }
    //設置連接超時時間
    if (0 != zkConfig.getConnectionTimeoutMilliseconds()) {
        builder.connectionTimeoutMs(zkConfig.getConnectionTimeoutMilliseconds());
    }
    if (!Strings.isNullOrEmpty(zkConfig.getDigest())) {
        builder.authorization("digest", zkConfig.getDigest().getBytes(StandardCharsets.UTF_8))
                .aclProvider(new ACLProvider() {
                
                    @Override
                    public List<ACL> getDefaultAcl() {
                        return ZooDefs.Ids.CREATOR_ALL_ACL;
                    }
                
                    @Override
                    public List<ACL> getAclForPath(final String path) {
                        return ZooDefs.Ids.CREATOR_ALL_ACL;
                    }
                });
    }
    client = builder.build();
    //zookeeper 客戶端開始啟動
    client.start();
    try {
        //zookeeper 客戶端一直連接
        if (!client.blockUntilConnected(zkConfig.getMaxSleepTimeMilliseconds() * zkConfig.getMaxRetries(), TimeUnit.MILLISECONDS)) {
            client.close();
            throw new KeeperException.OperationTimeoutException();
        }
        //CHECKSTYLE:OFF
    } catch (final Exception ex) {
        //CHECKSTYLE:ON
        RegExceptionHandler.handleException(ex);
    }
}

第二件事：配置事件追蹤資料庫，用於保存job運行記錄

ElasticJobTracingConfiguration.java

/**
 * Create a bean of tracing DataSource.
 *
 * @param tracingProperties tracing Properties
 * @return tracing DataSource
 */
@Bean("tracingDataSource")
//spring中註入bean name 為tracingDataSource的job資料庫連接信息
public DataSource tracingDataSource(final TracingProperties tracingProperties) {
    //獲取elastic-job 資料庫配置
    DataSourceProperties dataSource = tracingProperties.getDataSource();
    if (dataSource == null) {
        return null;
    }
    HikariDataSource tracingDataSource = new HikariDataSource();
    tracingDataSource.setJdbcUrl(dataSource.getUrl());
    BeanUtils.copyProperties(dataSource, tracingDataSource);
    return tracingDataSource;
}


/**
 * Create a bean of tracing configuration.
 *
 * @param dataSource required by constructor
 * @param tracingDataSource tracing ataSource
 * @return a bean of tracing configuration
 */
@Bean
@ConditionalOnBean(DataSource.class)
@ConditionalOnProperty(name = "elasticjob.tracing.type", havingValue = "RDB")
public TracingConfiguration<DataSource> tracingConfiguration(final DataSource dataSource, @Nullable final DataSource tracingDataSource) {
    /**
     * dataSource 是業務資料庫
     * tracingDataSource 是job資料庫
     * 當配置elasticjob.tracing.type = RDB時，如果單獨配置job資料庫是，預設使用job資料庫作為job運行軌跡的記錄
     * 但這邊同時業務資料庫和job追蹤資料庫同時註入是，mybatis-plus 結合@Table 使用的時候，很有可能找不到正確對應的數據源
     */
    DataSource ds = tracingDataSource;
    if (ds == null) {
        ds = dataSource;
    }
    return new TracingConfiguration<>("RDB", ds);
}

通過elasticjob.tracing.type=RDB的配置開啟事件追蹤功能，這邊job的事件追蹤數據源可以和業務數據源配置不一樣。

第三件事：解析所有job配置文件

ElasticJobBootstrapConfiguration.class

public void createJobBootstrapBeans() {
    //獲取job配置
    ElasticJobProperties elasticJobProperties = applicationContext.getBean(ElasticJobProperties.class);
    //獲取單利註冊對象
    SingletonBeanRegistry singletonBeanRegistry = ((ConfigurableApplicationContext) applicationContext).getBeanFactory();
    //獲取註入zookeeper 客戶端
    CoordinatorRegistryCenter registryCenter = applicationContext.getBean(CoordinatorRegistryCenter.class);
    //獲取job事件追蹤
    TracingConfiguration<?> tracingConfig = getTracingConfiguration();
    //構造JobBootstraps
    constructJobBootstraps(elasticJobProperties, singletonBeanRegistry, registryCenter, tracingConfig);
}

重要的是constructJobBootstraps 這個方法，來看下

private void constructJobBootstraps(final ElasticJobProperties elasticJobProperties, final SingletonBeanRegistry singletonBeanRegistry,
                                    final CoordinatorRegistryCenter registryCenter, final TracingConfiguration<?> tracingConfig) {
    //遍歷配置的每一個job
    for (Map.Entry<String, ElasticJobConfigurationProperties> entry : elasticJobProperties.getJobs().entrySet()) {
        ElasticJobConfigurationProperties jobConfigurationProperties = entry.getValue();
        //校驗 job class 和 type 都為空拋異常
        Preconditions.checkArgument(null != jobConfigurationProperties.getElasticJobClass()
                        || !Strings.isNullOrEmpty(jobConfigurationProperties.getElasticJobType()),
                "Please specific [elasticJobClass] or [elasticJobType] under job configuration.");
        //校驗 job class 和 type 都有 報相互排斥
        Preconditions.checkArgument(null == jobConfigurationProperties.getElasticJobClass()
                        || Strings.isNullOrEmpty(jobConfigurationProperties.getElasticJobType()),
                "[elasticJobClass] and [elasticJobType] are mutually exclusive.");


        if (null != jobConfigurationProperties.getElasticJobClass()) {
            //通過class 註入job
            registerClassedJob(entry.getKey(), entry.getValue().getJobBootstrapBeanName(), singletonBeanRegistry, registryCenter, tracingConfig, jobConfigurationProperties);
        } else if (!Strings.isNullOrEmpty(jobConfigurationProperties.getElasticJobType())) {
            //通過type 註入job
            registerTypedJob(entry.getKey(), entry.getValue().getJobBootstrapBeanName(), singletonBeanRegistry, registryCenter, tracingConfig, jobConfigurationProperties);
        }
    }
}

Job 有兩種類型的註入，第一種是是class,配置成job的全路徑信息註入再來看看registerClassedJob 方法里的內容

private void registerClassedJob(final String jobName, final String jobBootstrapBeanName, final SingletonBeanRegistry singletonBeanRegistry, final CoordinatorRegistryCenter registryCenter,
                                final TracingConfiguration<?> tracingConfig, final ElasticJobConfigurationProperties jobConfigurationProperties) {
    //獲取job配置
    JobConfiguration jobConfig = jobConfigurationProperties.toJobConfiguration(jobName);
    //配置job事件追蹤
    jobExtraConfigurations(jobConfig, tracingConfig);
    //獲取job類型
    ElasticJob elasticJob = applicationContext.getBean(jobConfigurationProperties.getElasticJobClass());
    //沒有配置cron表達式 就初始化為OneOffJobBootstrap對象，一次性任務
    if (Strings.isNullOrEmpty(jobConfig.getCron())) {
        Preconditions.checkArgument(!Strings.isNullOrEmpty(jobBootstrapBeanName), "The property [jobBootstrapBeanName] is required for One-off job.");
        singletonBeanRegistry.registerSingleton(jobBootstrapBeanName, new OneOffJobBootstrap(registryCenter, elasticJob, jobConfig));
    } else {
        //有配置cron表達式 就初始化為ScheduleJobBootstrap對象，定時任務
        //設置bean name
        String beanName = !Strings.isNullOrEmpty(jobBootstrapBeanName) ? jobBootstrapBeanName : jobConfig.getJobName() + "ScheduleJobBootstrap";
        //註入ScheduleJobBootstrap對象為單利對象
        singletonBeanRegistry.registerSingleton(beanName, new ScheduleJobBootstrap(registryCenter, elasticJob, jobConfig));
    }
}

Class 類型註入的job有兩種類型 1.ScheduleJobBootstrap：定時任務類型的job。 2.OneOffJobBootstrap：一定次job類型。看下定義的new ScheduleJobBootstrap 方法

public JobScheduler(final CoordinatorRegistryCenter regCenter, final ElasticJob elasticJob, final JobConfiguration jobConfig) {
    Preconditions.checkArgument(null != elasticJob, "Elastic job cannot be null.");
    this.regCenter = regCenter;
    //獲取job監聽器
    Collection<ElasticJobListener> jobListeners = getElasticJobListeners(jobConfig);
    // 集成所有操作zookeeper 節點的services,job 監聽器
    setUpFacade = new SetUpFacade(regCenter, jobConfig.getJobName(), jobListeners);
    //獲取當前job名稱
    String jobClassName = JobClassNameProviderFactory.getProvider().getJobClassName(elasticJob);
    //zookeeper節點 {namespace}/{jobclassname}/config 放置job配置信息
    this.jobConfig = setUpFacade.setUpJobConfiguration(jobClassName, jobConfig);
    // 集成所有操作zookeeper 節點的services
    schedulerFacade = new SchedulerFacade(regCenter, jobConfig.getJobName());
    jobFacade = new LiteJobFacade(regCenter, jobConfig.getJobName(), jobListeners, findTracingConfiguration().orElse(null));
    //檢驗job配置
    validateJobProperties();
    //定義job執行器
    jobExecutor = new ElasticJobExecutor(elasticJob, this.jobConfig, jobFacade);
    //監聽器里註入GuaranteeService
    setGuaranteeServiceForElasticJobListeners(regCenter, jobListeners);
    //創建定時任務，開始執行
    jobScheduleController = createJobScheduleController();
}

看下createJobScheduleController

private JobScheduleController createJobScheduleController() {
    JobScheduleController result = new JobScheduleController(createScheduler(), createJobDetail(), getJobConfig().getJobName());
    //註冊job
    JobRegistry.getInstance().registerJob(getJobConfig().getJobName(), result);
    //註冊器開始運行
    registerStartUpInfo();
    return result;
}

看下registerStartUpInfo方法

public void registerStartUpInfo(final boolean enabled) {
    //開始所有的監聽器
    listenerManager.startAllListeners();
    //選舉leader /{namespace}/leader/election/instance 放置選舉出來的伺服器
    leaderService.electLeader();
    //{namespace}/{ipservers} 設置enable處理
    serverService.persistOnline(enabled);
    //臨時節點   /{namespave}/instances 放置運行服務實例信息
    instanceService.persistOnline();
    //開啟一個非同步服務
    if (!reconcileService.isRunning()) {
        reconcileService.startAsync();
    }
}

這裡實行的操作： 1.開啟所有監聽器處理 2.leader選舉 3.持久化節點數據 4.開啟非同步服務 第四步：4.識別job類型，在zookeeper節點上處理job節點數據，運行定時任務job.

@Override
public void run(final String... args) {
    log.info("Starting ElasticJob Bootstrap.");
    applicationContext.getBeansOfType(ScheduleJobBootstrap.class).values().forEach(ScheduleJobBootstrap::schedule);
    log.info("ElasticJob Bootstrap started.");
}

獲取到所有的定時任務job(ScheduleJobBootstrap類型)，執行schedule方法，底層實際使用quartz框架運行定時任務。