Chapter 41. Remote Task Execution

Tasks, or business logic, can run directly on JBoss Data Grid servers, which means task execution is close to the data and uses the resources of all nodes in the cluster.

You can bundle tasks in Java executable files and deploy them to server instances where you can run the executables programmatically.

To create a task for remote execution, you must create a .jar file that contains a class that implements the org.infinispan.tasks.ServerTask interface.

The following methods are required in the implementation:

The following methods are optional in the implementation:

The following provides an example class that implements the org.infinispan.tasks.ServerTask interface:

public class HelloTask implements ServerTask<String> {

   private TaskContext ctx;

   //Set the task context.
   @Override
   public void setTaskContext(TaskContext ctx) {
      this.ctx = ctx;
   }

   //Take the name of a person as a parameter.
   //Return a greeting with that person's name.
   @Override
   public String call() throws Exception {
      String name = (String) ctx.getParameters().get().get("name");
      return "Hello " + name;
   }

   //Return a unique name that clients can use to invoke the task.
   @Override
   public String getName() {
      return "hello-task";
   }

}

After you create a remote task and bundle it into a .jar file, you can deploy it to a JBoss Data Grid server instance with one of the following options:

You can remove remote tasks from the running instances of JBoss Data Grid as follows:

If authorization is enabled on the JBoss Data Grid server, only users with EXEC permissions can run remote tasks. If authorization is not enabled, any user can run remote tasks.

Remote tasks can have additional user roles specified with the getAllowedRole method. In this case, users must belong to the role to run remote tasks.

To execute a previously deployed task call execute(String taskName, Map parameters) on the desired cache.

The following example shows how to run a task named sampleTask:

import org.infinispan.client.hotrod.*;
import java.util.*;
[...]
String TASK_NAME = "sampleTask";

RemoteCacheManager rcm = new RemoteCacheManager();
RemoteCache remoteCache = rcm.getCache();

// Assume the task takes a single parameter, and will return a result
Map<String, String> params = new HashMap<>();
params.put("name", "James");

String result = (String) remoteCache.execute(TASK_NAME, params);