10.8. Event Listener

Presto supports custom event listeners that are invoked for the followingevents:

• Query creation
• Query completion (success or failure)
• Split completion (success or failure)This functionality enables development of custom logging, debugging andperformance analysis plugins. In a Presto cluster, only a single eventlistener plugin can be active at a time .

Implementation

EventListenerFactory is responsible for creating anEventListener instance. It also defines an EventListenername which is used by the administrator in a Presto configuration.Implementations of EventListener implement methods for the event typesthey are interested in handling.

The implementation of EventListener and EventListenerFactorymust be wrapped as a plugin and installed on the Presto cluster.

Configuration

After a plugin that implements EventListener andEventListenerFactory has been installed on the coordinator, it isconfigured using an etc/event-listener.properties file. All of theproperties other than event-listener.name are specific to theEventListener implementation.

The event-listener.name property is used by Presto to find a registeredEventListenerFactory based on the name returned byEventListenerFactory.getName(). The remaining properties are passedas a map to EventListenerFactory.create().

Example configuration file:

event-listener.name=custom-event-listener
custom-property1=custom-value1
custom-property2=custom-value2