elastic-job源码（1）- job自动装配

版本：3.1.0-SNAPSHOT

git地址：https://github.com/apache/shardingsphere-elasticjob

Maven 坐标

<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启动类的时候，会自动加载ElasticJobLiteAutoConfiguration，接下来看下ElasticJobLiteAutoConfiguration中所做的处理。

ElasticJobLiteAutoConfiguration.java

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


/**
 * elastic job 开关
 * elasticjob.enabled.ture默认为true
 */
@ConditionalOnProperty(name = "elasticjob.enabled", havingValue = "true", matchIfMissing = true)


/**
 * 导入
 * ElasticJobRegistryCenterConfiguration.class 注册中心配置
 * ElasticJobTracingConfiguration.class job事件追踪配置
 * ElasticJobSnapshotServiceConfiguration.class 快照配置
 */
@Import({ElasticJobRegistryCenterConfiguration.class, ElasticJobTracingConfiguration.class, ElasticJobSnapshotServiceConfiguration.class})


/**
 * job相关配置信息
 */
@EnableConfigurationProperties(ElasticJobProperties.class)
public class ElasticJobLiteAutoConfiguration {
    
    @Configuration(proxyBeanMethods = false)
    /**
     * ElasticJobBootstrapConfiguration.class  创建job beans 注入spring容器
     * ScheduleJobBootstrapStartupRunner.class  执行类型为ScheduleJobBootstrap.class 的job开始运行
     */
    @Import({ElasticJobBootstrapConfiguration.class, ScheduleJobBootstrapStartupRunner.class})
    protected static class ElasticJobConfiguration {
    }
}

Elastic-job 是利用zookeeper 实现分布式job的功能，所以在自动装配的时候，需要有zookeeper注册中心的配置。

自动装配主要做了4件事事

1.配置zookeeper 客户端信息，启动连接zookeeper.

2.配置事件追踪数据库，用于保存job运行记录

3.解析所有job配置文件，将所有job的bean放置在spring 单例bean中

4.识别job类型，在zookeeper节点上处理job节点数据，运行定时任务job.

第一件事：配置zookeeper 客户端信息，启动连接zookeeper.

ZookeeperRegistryCenter.class

public void init() {
    log.debug("Elastic job: zookeeper registry center init, server lists is: {}.", zkConfig.getServerLists());
    CuratorFrameworkFactory.Builder builder = CuratorFrameworkFactory.builder()
            //设置zookeeper 服务器地址
            .connectString(zkConfig.getServerLists())
            //设置重试机制
            .retryPolicy(new ExponentialBackoffRetry(zkConfig.getBaseSleepTimeMilliseconds(), zkConfig.getMaxRetries(), zkConfig.getMaxSleepTimeMilliseconds()))
            //设置命名空间，zookeeper节点名称
            .namespace(zkConfig.getNamespace());
    //设置session超时时间
    if (0 != zkConfig.getSessionTimeoutMilliseconds()) {
        builder.sessionTimeoutMs(zkConfig.getSessionTimeoutMilliseconds());
    }
    //设置连接超时时间
    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 客户端开始启动
    client.start();
    try {
        //zookeeper 客户端一直连接
        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：配置事件追踪数据库，用于保存job运行记录

ElasticJobTracingConfiguration.java

/**
 * Create a bean of tracing DataSource.
 *
 * @param tracingProperties tracing Properties
 * @return tracing DataSource
 */
@Bean("tracingDataSource")
//spring中注入bean name 为tracingDataSource的job数据库连接信息
public DataSource tracingDataSource(final TracingProperties tracingProperties) {
    //获取elastic-job 数据库配置
    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 是业务数据库
     * tracingDataSource 是job数据库
     * 当配置elasticjob.tracing.type = RDB时，如果单独配置job数据库是，默认使用job数据库作为job运行轨迹的记录
     * 但这边同时业务数据库和job追踪数据库同时注入是，mybatis-plus 结合@Table 使用的时候，很有可能找不到正确对应的数据源
     */
    DataSource ds = tracingDataSource;
    if (ds == null) {
        ds = dataSource;
    }
    return new TracingConfiguration<>("RDB", ds);
}

通过elasticjob.tracing.type=RDB的配置开启事件追踪功能，这边job的事件追踪数据源可以和业务数据源配置不一样。

第三件事：解析所有job配置文件

ElasticJobBootstrapConfiguration.class

public void createJobBootstrapBeans() {
    //获取job配置
    ElasticJobProperties elasticJobProperties = applicationContext.getBean(ElasticJobProperties.class);
    //获取单利注册对象
    SingletonBeanRegistry singletonBeanRegistry = ((ConfigurableApplicationContext) applicationContext).getBeanFactory();
    //获取注入zookeeper 客户端
    CoordinatorRegistryCenter registryCenter = applicationContext.getBean(CoordinatorRegistryCenter.class);
    //获取job事件追踪
    TracingConfiguration<?> tracingConfig = getTracingConfiguration();
    //构造JobBootstraps
    constructJobBootstraps(elasticJobProperties, singletonBeanRegistry, registryCenter, tracingConfig);
}

重要的是constructJobBootstraps 这个方法，来看下

private void constructJobBootstraps(final ElasticJobProperties elasticJobProperties, final SingletonBeanRegistry singletonBeanRegistry,
                                    final CoordinatorRegistryCenter registryCenter, final TracingConfiguration<?> tracingConfig) {
    //遍历配置的每一个job
    for (Map.Entry<String, ElasticJobConfigurationProperties> entry : elasticJobProperties.getJobs().entrySet()) {
        ElasticJobConfigurationProperties jobConfigurationProperties = entry.getValue();
        //校验 job class 和 type 都为空抛异常
        Preconditions.checkArgument(null != jobConfigurationProperties.getElasticJobClass()
                        || !Strings.isNullOrEmpty(jobConfigurationProperties.getElasticJobType()),
                "Please specific [elasticJobClass] or [elasticJobType] under job configuration.");
        //校验 job class 和 type 都有 报相互排斥
        Preconditions.checkArgument(null == jobConfigurationProperties.getElasticJobClass()
                        || Strings.isNullOrEmpty(jobConfigurationProperties.getElasticJobType()),
                "[elasticJobClass] and [elasticJobType] are mutually exclusive.");


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

Job 有两种类型的注入，第一种是是class,配置成job的全路径信息注入

再来看看registerClassedJob 方法里的内容

private void registerClassedJob(final String jobName, final String jobBootstrapBeanName, final SingletonBeanRegistry singletonBeanRegistry, final CoordinatorRegistryCenter registryCenter,
                                final TracingConfiguration<?> tracingConfig, final ElasticJobConfigurationProperties jobConfigurationProperties) {
    //获取job配置
    JobConfiguration jobConfig = jobConfigurationProperties.toJobConfiguration(jobName);
    //配置job事件追踪
    jobExtraConfigurations(jobConfig, tracingConfig);
    //获取job类型
    ElasticJob elasticJob = applicationContext.getBean(jobConfigurationProperties.getElasticJobClass());
    //没有配置cron表达式 就初始化为OneOffJobBootstrap对象，一次性任务
    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表达式 就初始化为ScheduleJobBootstrap对象，定时任务
        //设置bean name
        String beanName = !Strings.isNullOrEmpty(jobBootstrapBeanName) ? jobBootstrapBeanName : jobConfig.getJobName() + "ScheduleJobBootstrap";
        //注入ScheduleJobBootstrap对象为单利对象
        singletonBeanRegistry.registerSingleton(beanName, new ScheduleJobBootstrap(registryCenter, elasticJob, jobConfig));
    }
}

Class 类型注入的job有两种类型

1.ScheduleJobBootstrap：定时任务类型的job。

2.OneOffJobBootstrap：一定次job类型。

看下定义的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;
    //获取job监听器
    Collection<ElasticJobListener> jobListeners = getElasticJobListeners(jobConfig);
    // 集成所有操作zookeeper 节点的services,job 监听器
    setUpFacade = new SetUpFacade(regCenter, jobConfig.getJobName(), jobListeners);
    //获取当前job名称
    String jobClassName = JobClassNameProviderFactory.getProvider().getJobClassName(elasticJob);
    //zookeeper节点 {namespace}/{jobclassname}/config 放置job配置信息
    this.jobConfig = setUpFacade.setUpJobConfiguration(jobClassName, jobConfig);
    // 集成所有操作zookeeper 节点的services
    schedulerFacade = new SchedulerFacade(regCenter, jobConfig.getJobName());
    jobFacade = new LiteJobFacade(regCenter, jobConfig.getJobName(), jobListeners, findTracingConfiguration().orElse(null));
    //检验job配置
    validateJobProperties();
    //定义job执行器
    jobExecutor = new ElasticJobExecutor(elasticJob, this.jobConfig, jobFacade);
    //监听器里注入GuaranteeService
    setGuaranteeServiceForElasticJobListeners(regCenter, jobListeners);
    //创建定时任务，开始执行
    jobScheduleController = createJobScheduleController();
}

看下createJobScheduleController

private JobScheduleController createJobScheduleController() {
    JobScheduleController result = new JobScheduleController(createScheduler(), createJobDetail(), getJobConfig().getJobName());
    //注册job
    JobRegistry.getInstance().registerJob(getJobConfig().getJobName(), result);
    //注册器开始运行
    registerStartUpInfo();
    return result;
}

看下registerStartUpInfo方法

public void registerStartUpInfo(final boolean enabled) {
    //开始所有的监听器
    listenerManager.startAllListeners();
    //选举leader /{namespace}/leader/election/instance 放置选举出来的服务器
    leaderService.electLeader();
    //{namespace}/{ipservers} 设置enable处理
    serverService.persistOnline(enabled);
    //临时节点   /{namespave}/instances 放置运行服务实例信息
    instanceService.persistOnline();
    //开启一个异步服务
    if (!reconcileService.isRunning()) {
        reconcileService.startAsync();
    }
}

这里实行的操作：

1.开启所有监听器处理

2.leader选举

3.持久化节点数据

4.开启异步服务

第四步：4.识别job类型，在zookeeper节点上处理job节点数据，运行定时任务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.");
}

获取到所有的定时任务job(ScheduleJobBootstrap类型)，执行schedule方法，底层实际使用quartz框架运行定时任务。

原文链接：https://www.cnblogs.com/lingyujuan/p/17357040.html

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elastic-job源码（1）- job自动装配

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