Running async jobs in dropwizard, and polling their status - spring

Question

In dropwizard, I need to implement asynchronous jobs and poll their status.
I have 2 endpoints for this in resource:
#Path("/jobs")
#Component
public class MyController {
#POST
#Produces(MediaType.APPLICATION_JSON)
public String startJob(#Valid MyRequest request) {
return 1111;
}
#GET
#Path("/{jobId}")
#Produces(MediaType.APPLICATION_JSON)
public JobStatus getJobStatus(#PathParam("id") String jobId) {
return JobStatus.READY;
}
}
I am considering to use quartz to start job, but only single time and without repeating. And when requesting status, I will get trigger status. But the idea of using quartz for none-scheduled usage looks weird.
Is there any better approaches for this? Maybe dropwizard provides better tools itself? Will appriciate any advices.
UPDATE: I also looking at https://github.com/gresrun/jesque, but can not find any way to poll the status of running job.

Answer 1

You can use the Managed interface. In the snippet below I am using the ScheduledExecutorService to exuecute jobs, but you can use Quartz instead if you like. I prefer working with ScheduledExecutorService as it is simpler and easier...
first step is to register your managed service.
environment.lifecycle().manage(new JobExecutionService());
Second step is to write it.
/**
* A wrapper around the ScheduledExecutorService so all jobs can start when the server starts, and
* automatically shutdown when the server stops.
* #author Nasir Rasul {#literal nasir#rasul.ca}
*/
public class JobExecutionService implements Managed {
private final ScheduledExecutorService service = Executors.newScheduledThreadPool(2);
#Override
public void start() throws Exception {
System.out.println("Starting jobs");
service.scheduleAtFixedRate(new HelloWorldJob(), 1, 1, TimeUnit.SECONDS);
}
#Override
public void stop() throws Exception {
System.out.println("Shutting down");
service.shutdown();
}
}
and the job itself
/**
* A very simple job which just prints the current time in millisecods
* #author Nasir Rasul {#literal nasir#rasul.ca}
*/
public class HelloWorldJob implements Runnable {
/**
* When an object implementing interface <code>Runnable</code> is used
* to create a thread, starting the thread causes the object's
* <code>run</code> method to be called in that separately executing
* thread.
* <p>
* The general contract of the method <code>run</code> is that it may
* take any action whatsoever.
*
* #see Thread#run()
*/
#Override
public void run() {
System.out.println(System.currentTimeMillis());
}
}
As mentioned in the comment below, if you use Runnable, you can Thread.getState(). Please refer to Get a List of all Threads currently running in Java. You may still need some intermediary pieces depending on how you're wiring you application.