JarCastingCloud Scheduler
Cloud scheduler is a zookeeper based scheduler for cloud environment. It heavily rely on CompletableFuture introduced in JDK 8. But with minimum dependencies.
Design goal
- Minimum Dependencies: Cloud Scheduler been split into multiple projects in order to minimize third party dependencies.
- cloudscheduler-api: Define APIs and data models, do not depend on any third party library.
- cloudscheduler-codec-json: Jackson based entity codec implementations. Depends on
- cloudscheduler-api
- jackson-core
- jackson-databind
- jackson-annotations
- jackson-module-parameter-names
- jackson-datatype-jdk8
- jackson-datatype-jsr310
- cloudscheduler-codec-protobuf: Protostuff based entity codec implementations. Depends on
- cloudscheduler-api
- protostuff-api
- protostuff-core
- protostuff-runtime
- protostuff-collectionschema
- cloudscheduler-core: Implementation of cloud scheduler. Depends on
- cloudscheduler-api
- slf4j-api
- zookeeper
- cloudscheduler-spring: Spring framework application context based job factory implementation. Used to integrate with spring framework. Depends on:
- cloudscheduler-api
- spring-context.jar
- Thread module
- Asynchronized thread modeling, no blocking logic.
- Job runs in user's own thread pool.
- Minimum threads in cloud scheduler.
How to use
Dependencies
You will need at least:
cloudscheduler-apicloudscheduler-core- One of codec implementation. Default is:
cloudscheduler-codec-json
If you want to use it in spring environment, you will also need
cloudscheduler-spring: JobFactory implementation that will retrieve Job instance from spring beans
Standalone application
Dependency definition:
Maven
<dependencies>
<dependency>
<groupId>io.github.cloudscheduler</groupId>
<artifactId>cloudscheduler-core</artifactId>
<version>${version}</version>
</dependency>
<dependency>
<groupId>io.github.cloudscheduler</groupId>
<artifactId>cloudscheduler-codec-json</artifactId>
<version>${version}</version>
</dependency>
</dependencies>
Initial a CloudSchedulerManager
// Create a thread pool you want to use to execute your job.
ExecutorService threadPool = Executors.newCacheThreadPool();
// Create a cloud scheduler manager
CloudSchedulerManager manager = CloudSchedulerManager.newBuilder(zkUrl)
.setZkTimeout(zkTimeout)
.setThreadPool(threadPool)
.build();
// Start cloud scheduler manager
manager.start();
Create Scheduler
End user will use API on Scheduler to schedule job
// Create a zookeeper
ZooKeeper zkClient = new ZooKeeper(zkUrl, zkTimeout, watcher);
// Create a scheduler from zookeeper
Scheduler scheduler = new SchedulerImpl(zkClient);
Create a job class
public class MyJob extends Job {
public void execute(JobExecutionContext ctx) {
// Your business logic here
}
}
Schedule the job
// Run job now without repeat
scheduler.runNow(MyJob.class);
// Run job at a given time without repeat
Instant start = Instant.now().plus(Duration.ofMinutes(5));
scheduler.runOnce(MyJob.class, start)
Shutdown CloudSchedulerManager after everything done
manager.shutdown();
Spring application
Dependency definition:
Maven
<dependencies>
<dependency>
<groupId>io.github.cloudscheduler</groupId>
<artifactId>cloudscheduler-core</artifactId>
<version>${version}</version>
</dependency>
<dependency>
<groupId>io.github.cloudscheduler</groupId>
<artifactId>cloudscheduler-codec-json</artifactId>
<version>${version}</version>
</dependency>
<dependency>
<groupId>io.github.cloudscheduler</groupId>
<artifactId>cloudscheduler-spring</artifactId>
<version>${version}</version>
</dependency>
</dependencies>
Define beans
<bean id="csmBuilder" class="io.github.cloudscheduler.CloudSchedulerManager$Builder"
factory-method="newBuilder">
<constructor-arg>zookeeper1:2181,zookeeeper2:2181,zookeeper3:2181/cloudscheduler</constructor-arg>
<property name="zkTimeout">5000</property>
<property name="threadPool"><ref bean="MyThreadPool" /></property>
</bean>
<bean class="io.github.cloudscheduler.CloudSchedulerManager" factory-bean="csmBuilder" factory-method="build"
init-method="start" destroy-method="shutdown" />
<bean class="io.github.cloudscheduler.SchedulerImpl">
<constructor-arg index="1"><ref bean="zookeeper"></ref></constructor-arg>
</bean>
Wire beans
@Autowired
private Scheduler scheduler;
...
scheduler.runNow(MyJob.class);
More complicated job
- Start after 1 hour, repeat every 5 hour for 10 times
JobDefinition jobDef = JobDefinition.newBuilder(MyJob.class)
.initialDelay(Duration.ofHours(1))
.fixedRate(Duration.ofHours(5))
.repeat(10)
.build();
scheduler.schedule(jobDef);
- Start after 1 hour, repeat after 5 hour of previous job done for 3 times
JobDefinition jobDef = JobDefinition.newBuilder(MyJob.class)
.initialDelay(Duration.ofHours(1))
.fixedDelay(Duration.ofHours(5))
.repeat(3)
.build();
scheduler.schedule(jobDef);
- Use crontab format to define job (run at 12 every day). Allow next job start even previous job not done yet
JobDefinition jobDef = JobDefinition.newBuilder(MyJob.class)
.cron("0 12 * * *")
.allowDupInstances()
.build();
scheduler.schedule(jobDef);
- Create an one time job, but run on all worker nodes
JobDefinition jobDef = JobDefinition.newBuilder(MyJob.class)
.global()
.build();
scheduler.schedule(jobDef);