Creating A New AutoScale Extension

To create a new AutoScale extension, it’s recommended that you use one of the existing extensions as a base. Extensions are expected to be split into an implementation module and an admin console plugin, and utilize the various interfaces, abstract classes, and utility methods found within the three core modules (autoscale-groups-api, autoscale-groups-core, and autoscale-groups-console).

It’s recommended that you place your two implementation modules under a parent aggregator module, similar as to how was done here with the autoscale-groups-nodes-plugin.

The Implementation Module

The implementation module is where the admin commands, services, and config bean interfaces should exist. The following is expected as a minimum:

  • A ConfigBean extension for ScalingGroup - This ConfigBean is the "type" of AutoScale Group, and as such should contain any extension specific attributes and elements. It is expected to follow the naming format of ${type}ScalingGroup (e.g. NodesScalingGroup).

  • A service extension for Scaler - This service should implement the scaleUp and scaleDown methods, and should be qualified with the ScalerFor annotation pointing at your ScalingGroup ConfigBean.

  • Create command - An admin command used to create a scaling group of your extension’s type. This command is expected to be in the format of create-${ScalingGroupExtensionName}, and to have a REST endpoint under its own config bean (e.g. the create-nodes-scaling-group command has a REST endpoint under the NodesScalingGroup config bean).

  • Get command - An admin command used to get the configuration of a scaling group of your extension’s type. This command is expected to be in the format of get-${ScalingGroupExtensionName}-configuration, and to have a REST endpoint under its own config bean (e.g. the get-nodes-scaling-group-configuration command has a REST endpoint under the NodesScalingGroup config bean).

  • Set command - An admin command used to set the configuration of a scaling group of your extension’s type. This command is expected to be in the format of set-${ScalingGroupExtensionName}-configuration, and to have a REST endpoint under its own config bean (e.g. the set-nodes-scaling-group-configuration command has a REST endpoint under the NodesScalingGroup config bean).

The Admin Console Plugin

The admin console plugin is where you add your tabs and pages for listing, creating, deleting, and editing AutoScale groups of your extension’s type. The "base" admin console plugin provides a tab group integration point that you can add your extension tabs to named fish.payara.admingui.extensions:autoScaleGroupsTab (done via your extension’s console-config.xml file).

Developer Documentation

AutoScale is split into a number of separate modules, but can be summarised into:

  • An API module

  • Two Core modules (base implementation module and a base Admin Console Plugin)

  • Extension modules

The API Module

This module contains the interfaces and abstract classes intended for use or extension within Payara Server and any extensions. More specifically, it contains:

  • The "group" ScalingGroups ConfigBean interface (representing the domain.xml elements and attributes) - this contains the list of all configured scaling groups

  • The "base" ScalingGroup ConfigBean interface - This is the ConfigBean interface any extension ConfigBean interfaces should extend from to create their own scaling group type.

  • The Scaler abstract class contract - This is the abstract class extensions should create an implementation service for. This service is used to perform the scaleUp and scaleDown operations.

  • The ScaleFor qualifier - This qualifier is used to link a Scaler service to a specific ScalingGroup, there is only ever meant to be one Scaler service for each ScalingGroup extension.

  • Abstract classes for creating the get, set, and create Admin Commands from.

This module is expected to be included in the server, regardless of what extension you choose to use.

The Core Modules

There are currently two core modules: a base implementation module, and a base Admin Console plugin.

Both of these modules are expected to be included in the server, regardless of what extension you choose to use.

The Base Implementation Module

This module contains generic admin commands and util classes:

  • The scale-up and scale-down admin commands - this command looks up the Scaler service for the ScalingGroup type attached to the Deployment Group to be scaled, and from it scales the Deployment Group up or down the requested amount.

  • The delete-scaling-group command is a generic command for deleting scaling groups - extensions do not need to provide their own delete commands unless you wish additional actions to be taken.

  • The list-scaling-groups command lists all configured scaling groups.

  • The get-deployment-group-scaling-group command returns the ScalingGroup attached to the provided Deployment Group

The Base Admin Console Plugin

This module contains common handler methods, the tab group that admin console plugin extensions should attach to, and a generic "Active AutoScale Group" page from which a user can see which AutoScale group is attached to a specific Deployment Group and scale it up or down.

Extension Modules

Extension modules are the implementations that provide the ability for Payara Server to scale across different environments. They consist of an implementation module and an admin console plugin. The implementation module provides the config beans, services, and admin commands for creating, configuring, and using an AutoScale group, while the admin console plugin contains the pages and tabs for doing the same from the admin console.