Apache ActiveMQ Artemis is designed to allow extra functionality to be added by creating a plugin. Multiple plugins can be registered at the same time and they will be chained together and executed in the order they are registered (i.e. the first plugin registered is always executed first).

Creating a plugin is very simple. It requires:

• Implementing the ActiveMQServerPlugin interface

• Making sure the plugin is on the classpath

• Registering it with the broker either via xml or programmatically.

Only the methods that you want to add behavior for need to be implemented as all of the interface methods are default methods.

1. Registering a Plugin

To register a plugin with by XML you need to add the broker-plugins element at the broker.xml. It is also possible to pass configuration to a plugin using the property child element(s). These properties (zero to many) will be read and passed into the plugin’s init(Map<String, String>) operation after the plugin has been instantiated.

<broker-plugins>
   <broker-plugin class-name="some.plugin.UserPlugin">
      <property key="property1" value="val_1" />
      <property key="property2" value="val_2" />
   </broker-plugin>
</broker-plugins>

2. Registering a Plugin Programmatically

For registering a plugin programmatically you need to call the registerBrokerPlugin() method and pass in a new instance of your plugin. In the example below assuming your plugin is called UserPlugin, registering it looks like the following:

...
Configuration config = new ConfigurationImpl();
...
config.registerBrokerPlugin(new UserPlugin());

3. Using the LoggingActiveMQServerPlugin

The LoggingActiveMQServerPlugin logs specific broker events.

You can select which events are logged by setting the following configuration properties to true.

By default the LoggingActiveMQServerPlugin will not log any information. The logging is activated by setting one (or a selection) of the above configuration properties to true.

To configure the plugin, you can add the following configuration to the broker. In the example below both LOG_DELIVERING_EVENTS and LOG_SENDING_EVENTS will be logged by the broker.

<broker-plugins>
   <broker-plugin class-name="org.apache.activemq.artemis.core.server.plugin.impl.LoggingActiveMQServerPlugin">
      <property key="LOG_DELIVERING_EVENTS" value="true" />
      <property key="LOG_SENDING_EVENTS" value="true" />
   </broker-plugin>
</broker-plugins>

Most events in the LoggingActiveMQServerPlugin follow a beforeX and afterX notification pattern (e.g beforeCreateConsumer() and afterCreateConsumer()).

At Log Level INFO, the LoggingActiveMQServerPlugin logs an entry when an afterX notification occurs. By setting the logger org.apache.activemq.artemis.core.server.plugin.impl to DEBUG, log entries are generated for both beforeX and afterX notifications. Log level DEBUG will also log more information for a notification when available.

4. Using the NotificationActiveMQServerPlugin

The NotificationActiveMQServerPlugin can be configured to send extra notifications for specific broker events.

You can select which notifications are sent by setting the following configuration properties to true.

By default the NotificationActiveMQServerPlugin will not send any notifications. The plugin is activated by setting one (or a selection) of the above configuration properties to true.

To configure the plugin, you can add the following configuration to the broker. In the example below both SEND_CONNECTION_NOTIFICATIONS and SEND_SESSION_NOTIFICATIONS will be sent by the broker.

<broker-plugins>
   <broker-plugin class-name="org.apache.activemq.artemis.core.server.plugin.impl.NotificationActiveMQServerPlugin">
      <property key="SEND_CONNECTION_NOTIFICATIONS" value="true" />
      <property key="SEND_SESSION_NOTIFICATIONS" value="true" />
   </broker-plugin>
</broker-plugins>

5. Using the BrokerMessageAuthorizationPlugin

The BrokerMessageAuthorizationPlugin filters messages sent to consumers based on if they have a role that matches the value specified in a message property.

You can select which property will be used to specify the required role for consuming a message by setting the following configuration.

If the message does not have a property matching the configured ROLE_PROPERTY then the message will be sent to any consumer.

To configure the plugin, you can add the following configuration to the broker. In the example below ROLE_PROPERTY is set to permissions when that property is present messages will only be sent to consumers with a role matching its value.

<broker-plugins>
   <broker-plugin class-name="org.apache.activemq.artemis.core.server.plugin.impl.BrokerMessageAuthorizationPlugin">
      <property key="ROLE_PROPERTY" value="permissions" />
   </broker-plugin>
</broker-plugins>