activemq-artemis/docs/user-manual/en/broker-plugins.md

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Apache ActiveMQ Artemis Plugin Support

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, and registering it with the broker. Only the methods that you want to add behavior for need to be implemented as all of the interface methods are default methods.

Adding the plugin to the classpath

See the documentation on adding runtime dependencies to understand how to make your plugin available to the broker.

If you are using an embed system than you will need the jar under the regular classpath of your embedded application.

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.

<configuration ...>

    ...
    <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>
    ...

</configuration>

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());

Using the LoggingActiveMQServerPlugin

The LoggingActiveMQServerPlugin logs specific broker events.

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

Property Property Description
LOG_CONNECTION_EVENTS Log info when a Connection is created/destroy. Default `false`.
LOG_SESSION_EVENTS Log info when a Session is created/closed. Default `false`.
LOG_CONSUMER_EVENTS Logs info when a Consumer is created/closed. Default `false`.
LOG_DELIVERING_EVENTS Logs info when message is delivered to a consumer and when a message is acknowledged by a consumer. Default `false`
LOG_SENDING_EVENTS Logs info when a message has been sent to an address and when a message has been routed within the broker. Default `false`
LOG_INTERNAL_EVENTS Logs info when a queue created/destroyed, when a message is expired, when a bridge is deployed and when a critical failure occurs. Default `false`
LOG_ALL_EVENTS Logs info for all the above events. Default `false`

By default the LoggingActiveMQServerPlugin wil 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.

<configuration ...>

...
    <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>
...

</configuration>

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 Level, log entries are generated for both beforeX and afterX notifications. Log Level DEBUG will also log more information for a notification when available.