Event Listener

Presto supports custom event listeners that are invoked for the following events:

• Query creation
• Query completion (success or failure)
• Split completion (success or failure)

This functionality enables development of custom logging, debugging and performance analysis plugins. In a Presto cluster, only a single event listener plugin can be active at a time .

Implementation

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

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

Configuration

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

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

Example configuration file:

1. event-listener.name=custom-event-listener
2. custom-property1=custom-value1
3. custom-property2=custom-value2

Multiple Event Listeners

Multiple instances of the same, or different event listeners can be installed and configured by setting event-listener.config-files to a comma separated list of config files.

1. event-listener.config-files=etc/event-listener.properties,etc/event-listener-second.properties