Elastic-Job:动态添加任务,支持动态分片

多情只有春庭月,犹为离人照落花。

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概述

因项目中使用到定时任务,且服务部署多实例,因此需要解决定时任务重复执行的问题。即在同一时间点,每一个定时任务只在一个节点上执行。常见的开源方案,如 elastic-jobxxl-jobquartzsaturnopencronantares 等。最终决定使用elastic-jobelastic-job的亮点主要如下:
1. 基于quartz 定时任务框架为基础的,因此具备quartz的大部分功能
2. 使用zookeeper做协调,调度中心,更加轻量级
3. 支持任务的分片
4. 支持弹性扩容 , 可以水平扩展 , 当任务再次运行时,会检查当前的服务器数量,重新分片,分片结束之后才会继续执行任务
5. 失效转移,容错处理,当一台调度服务器宕机或者跟zookeeper断开连接之后,会立即停止作业,然后再去寻找其他空闲的调度服务器,来运行剩余的任务
6. 提供运维界面,可以管理作业和注册中心

但在实际开发中发现elastic-job对于动态添加的定时任务不支持分片。即在多实例情况下,在某个实例上动态添加任务,则该任务会一直在这一台节点上运行。如果需要在其它实例上运行,则需要以相同的参数调用其它实例接口。参考:elastic-job:动态进行任务的添加。在多次百度+google下发现Elastic-Job动态添加任务这里与楼主遇到了相同的问题。但经楼主测试动态添加任务的分片时好时坏,且只要在zookeeper中注册了任务,重启时任务还是会自动初始化。(关于对动态呢任务的描述,可以参考上面链接的描述,此处不在做过多的解释)。

解决

顺着尹大的思路,将任务的节点都集中管理起来,无论动态任务在哪个节点上进行注册,都需要将这个请求转发到其他的节点上进行初始化操作,这样就可以保证多节点分片的任务正常执行。

代码如下:

/**
     * 开启任务监听,当有任务添加时,监听zk中的数据增加,自动在其他节点也初始化该任务
     */
    public void monitorJobRegister() {
        CuratorFramework client = zookeeperRegistryCenter.getClient();
        @SuppressWarnings("resource")
        PathChildrenCache childrenCache = new PathChildrenCache(client, "/", true);
        PathChildrenCacheListener childrenCacheListener = new PathChildrenCacheListener() {
            public void childEvent(CuratorFramework client, PathChildrenCacheEvent event) throws Exception {
                ChildData data = event.getData();
                switch (event.getType()) {
                    case CHILD_ADDED:
                        String config = new String(client.getData().forPath(data.getPath() + "/config"));
                        Job job = JsonUtils.toBean(Job.class, config);
                        Object bean = null;
                        // 获取bean失败则添加任务
                        try {
                            bean = ctx.getBean("SpringJobScheduler" + job.getJobName());
                        } catch (BeansException e) {
                            logger.error("ERROR NO BEAN,CREATE BEAN SpringJobScheduler" + job.getJobName());
                        }
                        if (Objects.isNull(bean)) {
                            addJob(job);
                        }
                        break;
                    default:
                        break;
                }
            }
        };
        childrenCache.getListenable().addListener(childrenCacheListener);
        try {
            // https://blog.csdn.net/u010402202/article/details/79581575
            childrenCache.start(PathChildrenCache.StartMode.BUILD_INITIAL_CACHE);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

测试

测试动态添加定时任务,支持分片失效转移。

  1. 下载elastic-job-spring-boot-starter 使用maven 命令install到本地
  2. 创建 demo-elastic-job项目
    目录结构如下:
demo-elastic-job
├── mvnw
├── mvnw.cmd
├── src
│   ├── main
│   │   ├── java
│   │   │   └── com
│   │   │       └── example
│   │   │           └── demo
│   │   │               ├── job
│   │   │               │   ├── DynamicJob.java
│   │   │               │   └── TestJob.java
│   │   │               └── DemoApplication.java
│   │   └── resources
│   │       ├── application.yml
│   │       └── application-dev.yml
│   └── test
│       └── java
│           └── com
│               └── example
│                   └── demo
│                       └── DemoApplicationTests.java
├── pom.xml
└── demo.iml

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-recipes</artifactId>
            <version>2.10.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-framework</artifactId>
            <version>2.10.0</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>com.cxytiandi</groupId>
            <artifactId>elastic-job-spring-boot-starter</artifactId>
            <version>1.0.4</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

DemoApplication.java

package com.example.demo;

import com.cxytiandi.elasticjob.annotation.EnableElasticJob;
import com.cxytiandi.elasticjob.dynamic.service.JobService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
@EnableElasticJob
@ComponentScan(basePackages = {"com.cxytiandi", "com.example.demo"})
public class DemoApplication implements CommandLineRunner {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

    @Autowired
    private JobService jobService;

    @Override
    public void run(String... args) throws Exception {
        // 模拟初始化读取数据库 添加任务
//        Job job1 = new Job();
//        job1.setJobName("job1");
//        job1.setCron("0/10 * * * * ? ");
//        job1.setJobType("SIMPLE");
//        job1.setJobClass("com.example.demo.job.DynamicJob");
//        job1.setShardingItemParameters("");
//        job1.setShardingTotalCount(2);
//        jobService.addJob(job1);
//        Job job2 = new Job();
//        job2.setJobName("job2");
//        job2.setCron("0/10 * * * * ? ");
//        job2.setJobType("SIMPLE");
//        job2.setJobClass("com.example.demo.job.DynamicJob");
//        job2.setShardingItemParameters("0=A,1=B");
//        job2.setShardingTotalCount(2);
//        jobService.addJob(job2);
    }
}

TestJob.java

package com.example.demo.job;

import com.cxytiandi.elasticjob.annotation.ElasticJobConf;
import com.dangdang.ddframe.job.api.ShardingContext;
import com.dangdang.ddframe.job.api.simple.SimpleJob;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Component;

/**
 * Created by zhenglongfei on 2019/7/22
 *
 * @VERSION 1.0
 */
@Component
@Slf4j
@ElasticJobConf(name = "dayJob", cron = "0/10 * * * * ?", shardingTotalCount = 2,
        shardingItemParameters = "0=AAAA,1=BBBB", description = "简单任务", failover = true)
public class TestJob implements SimpleJob {
    @Override
    public void execute(ShardingContext shardingContext) {
        log.info("TestJob任务名:【{}】, 片数:【{}】, param=【{}】", shardingContext.getJobName(), shardingContext.getShardingTotalCount(),
                shardingContext.getShardingParameter());
    }
}

DynamicJob.java

package com.example.demo.job;

import com.dangdang.ddframe.job.api.ShardingContext;
import com.dangdang.ddframe.job.api.simple.SimpleJob;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

/**
 * Created by zhenglongfei on 2019/7/24
 *
 * @VERSION 1.0
 */
@Component
@Slf4j
public class DynamicJob implements SimpleJob {
    @Override
    public void execute(ShardingContext shardingContext) {


        switch (shardingContext.getShardingItem()) {
            case 0:
                log.info("【0】 is running");
                break;
            case 1:
                log.info("【1】 is running");
                break;
        }
    }
}

application.yml

elastic:
  job:
    zk:
      serverLists: 172.25.66.137:2181
      namespace: demo_test
server:
  port: 8082
spring:
  redis:
    host: 127.0.0.1
    port: 6379

测试结果

启动两个项目分别为80818082端口,使用REST API来动态的注册任务。
– job
https://raw.githubusercontent.com/longfeizheng/longfeizheng.github.io/master/images/java/java09.png

http://localhost:8081/job post
参数如下:

{
  "jobName": "DynamicJob01",
  "cron": "0/3 * * * * ?",
  "jobType": "SIMPLE",
  "jobClass": "com.example.demo.job.DynamicJob",
  "jobParameter": "test",
  "shardingTotalCount": 2,
  "shardingItemParameters": "0=AAAA,1=BBBB"
}

https://raw.githubusercontent.com/longfeizheng/longfeizheng.github.io/master/images/java/java10.gif

代码下载


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参考链接:
Elastic-Job动态添加任务
elastic-job:动态进行任务的添加
Curator之PathChildrenCache的那些坑

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