About Invocation Grids

ScaleOut’s Invocation Grid feature allows you to deploy and host your event handling code in a Java worker process that is launched and managed by the ScaleOut service.

Several advanced ScaleOut features take advantage of server-side events for fast, local processing of ScaleOut objects:

• Parallel Method Invocation (PMI)

• Stateful Stream Processing (PostEvent)

• Single-object Invocations

These server-side operations require you to deploy custom event-handling applications directly on the machines running the ScaleOut service. While it is possible to develop and manually deploy event-handling applications on ScaleOut hosts, ScaleOut’s Invocation Grid feature simplifies this work.

Downloading the JARs

The following sections detail how to configure a Gradle or Maven project to reference the InvocationGrid APIs. Alternatively, you can navigate to the repository and download the JAR manually.

GradleMaven

implementation group: 'com.scaleoutsoftware', name: 'invocationgrid', version: '2.0.11'

Typical Workflow

1. Create a Java project with your build tool of choice.

2. Reference the IG Hosting dependency (hosted on Maven Central)

3. Customize the project’s code to handle PMI, PostEvent, or Single-object Invocation operations.

4. Deploy the Invocation Grid project on a cluster of ScaleOut hosts using a simple launcher application.

Architecture

When deployed, your Invocation Grid project is decompressed to a temporary directory on all the ScaleOut hosts in your cluster, and the ScaleOut service launches it as a long-running worker process: Invocation Grid Deployment

The running IG worker processes handle PMI, PostEvent, and Single-object Invocation events for local objects.

If the Invocation Grid project needs to be updated, the project can be redeployed using the launcher. The ScaleOut hosts will be notified of the new worker process code, stop the existing worker process, and deploy/launch the new version.