Service job framework concepts

Introduction

Service job framework was created mainly to simplify work of grid operators and advanced users. These actors are in various interactions with grid - from submitting standard jobs and accessing data, through benchmarking and testing grid resources to deploying new applications on computing elements. Service job framework's responsibility is to gather all of the more complicated grid interactions in one common view and provide all needed resources to run and see results of such tasks.

g-Eclipse service job framework introduces two new views: Operator's Job and Operator's Job History with actions similar to Job's View. User can create new Operator's Jobs, submit them, resubmit existing jobs and see detailed informations about them, such as all results of this service job executions on each of the target resources. To see how running service jobs and their results are presented, please consult the screenshot below.

Service Job Framework

We distinguish two types of service jobs based on how the job is executed. If the service job is executed as a grid job, we will call it submittable service job, while the rest of the service jobs will be called basic service jobs. Framework provides two abstract classes for this two cases: eu.geclipse.servicejob.model.access.GridAccessServiceJob and eu.geclipse.servicejob.model.submittable.job.AbstractSubmittableServiceJob, as well as the abstract class for both of them - eu.geclipse.servicejob.model.AbstractServiceJob. When using mentioned abstraction developer is asked to implement only few methods needed to perform the service job and get the results.

We encourage all service job providers to use service job framework to introduce their grid tasks into g-Eclipse. As can be seen in the examples provided by g-Eclipse, this integration was successful for application deployment/uninstall, grid resources benchmarking and few others.

UI components

The UI part of the Service Job Framework is hidden from the developer. For proper implementation you only need to implement model classes of the Service Job Framework - all views and informations about your job will be presented to the user using this model classes.

The only UI part you should consider to extend is wizard for your service job. To add your service job to the service job wizard (see screenshot below) you need to contribute to the eu.geclipse.servicejob.servicejobProvider extension point by creating wizard extension. You will also need to provide implementation of the eu.geclipse.servicejob.ui.wizard.AbstractServiceJobWizardNode abstraction. See section Servce Job UI parts contribution.

Selecting Service Job

Submittable service jobs

Submittable service jobs are all grid tasks that need to submit grid job to get results. The usual steps are as follows:

1. Get all requested and optional data about the service job using wizard.
2. Create job description for each target resource.
3. Submit the job descriptions to proper job submission service.
4. Monitor submitted grid jobs.
5. When grid job finishes, download it's output and compute result.
6. When all grid jobs finish, compute the result of service job.

When writing new submittable service job developer is not required to create implementations of all of the above steps from the scratch. In fact, service job framework provides you with the job submission and monitoring, and it invokes appropriate methods from the underlying implementations when each grid job finishes. You are only asked to provide service-specific informations needed to perform your task on the grid.

For further detail, how can you implement new submittable service job, please proceed to How to implement submittable service job.

Direct Grid Access service jobs

In fact Direct Grid Access service jobs and their model representation eu.geclipse.servicejob.model.access.GridAccessServiceJob were introduced to provide distinguish from Submittable service jobs. Basically this category covers all use cases that doesn't fit to submittable services.

Common steps of those jobs are:

1. Get all requested and optional data about the service job using wizard.
2. Prepare the model classes containing all gathered information.
3. Contact the Grid and perform the desired operation.
4. When above operation finishes - compute the result of service job.

For more detials on how to implement Grid Access service job please consult Direct Grid Access Service Jobs section.