java-jobs-howto.md

type	title	linkTitle	weight	description
docs	How to: Author and manage Dapr Jobs in the Java SDK	How to: Author and manage Jobs	20000	How to get up and running with Jobs using the Dapr Java SDK

As part of this demonstration we will schedule a Dapr Job. The scheduled job will trigger an endpoint registered in the same app. With the provided jobs example, you will:

• Schedule a Job Job scheduling example
• Register an endpoint for the Jobs runtime to invoke as part of the schedule Endpoint Registration

This example uses the default configuration from dapr init in self-hosted mode.

Prerequisites

• Dapr CLI and initialized environment.
• Java JDK 11 (or greater):
  • Oracle JDK, or
  • OpenJDK
• Apache Maven, version 3.x.
• Docker Desktop

Set up the environment

Clone the Java SDK repo and navigate into it.

git clone https://github.com/dapr/java-sdk.git
cd java-sdk

Run the following command to install the requirements for running this jobs sample with the Dapr Java SDK.

mvn clean install -DskipTests

From the Java SDK root directory, navigate to the Dapr Workflow example.

cd examples

We'll run a command that starts the Dapr sidecar.

dapr run --app-id jobsapp --dapr-grpc-port 51439 --dapr-http-port 3500 --app-port 8080

Now, Dapr is listening for HTTP requests at http://localhost:3500 and internal Jobs gRPC requests at http://localhost:51439.

Register a job and Get its details

In the DemoJobsClient there are steps to Register a Job. Calling the scheduleJob on the DaprPreviewClient will schedule a job with the Dapr Runtime.

public class DemoJobsClient {

  /**
   * The main method of this app to register and fetch jobs.
   */
  public static void main(String[] args) throws Exception {
    try (DaprPreviewClient client = new DaprClientBuilder().withPropertyOverrides(overrides).buildPreviewClient()) {

      // Schedule a job.
      System.out.println("**** Scheduling a Job with name dapr-jobs-1 *****");
      ScheduleJobRequest scheduleJobRequest = new ScheduleJobRequest("dapr-job-1",
          JobSchedule.fromString("* * * * * *")).setData("Hello World!".getBytes());
      client.scheduleJob(scheduleJobRequest).block();

      System.out.println("**** Scheduling job dapr-jobs-1 completed *****");
    }
  }
}

and calling a getJob retrieves the created job details

client.getJob(new GetJobRequest("dapr-job-1")).block()

Command to run the DemoJobsClient

java -jar target/dapr-java-sdk-examples-exec.jar io.dapr.examples.jobs.DemoJobsClient

Sample output

**** Scheduling a Job with name dapr-jobs-1 *****
**** Scheduling job dapr-jobs-1 completed *****
**** Retrieving a Job with name dapr-jobs-1 *****

Set up an endpoint to be invoked when the job is triggered

The DemoJobsSpringApplication class starts a Spring Boot application that registers the endpoints specified in the JobsController This endpoint acts like a callback for the scheduled job requests.

@RestController
public class JobsController {

  /**
   * Handles jobs callback from Dapr.
   *
   * @param jobName name of the job.
   * @param payload data from the job if payload exists.
   * @return Empty Mono.
   */
  @PostMapping("/job/{jobName}")
  public Mono<Void> handleJob(@PathVariable("jobName") String jobName,
                              @RequestBody(required = false) byte[] payload) {
    System.out.println("Job Name: " + jobName);
    System.out.println("Job Payload: " + new String(payload));

    return Mono.empty();
  }
}

Parameters:

• jobName: The name of the job that triggered the callback.
• payload: Optional payload data associated with the job (as a byte array).

Command to run the Spring boot app:

java -jar target/dapr-java-sdk-examples-exec.jar io.dapr.examples.jobs.DemoJobsSpringApplication

Sample output

Job Name: dapr-job-1
Job Payload: Hello World!

Delete a scheduled job

public class DemoJobsClient {

  /**
   * The main method of this app to register and fetch jobs.
   */
  public static void main(String[] args) throws Exception {
    try (DaprPreviewClient client = new DaprClientBuilder().buildPreviewClient()) {

      // Get a job.
      System.out.println("**** Delete a Job with name dapr-jobs-1 *****");
      client.deleteJob(new DeleteJobRequest("dapr-job-1")).block();
    }
  }
}

Next steps

• [Learn more about Jobs]({{< ref jobs-overview.md >}})
• [Jobs API reference]({{< ref jobs_api.md >}})