Appendix E: Integrating with Existing Enterprise System Management : vCloud Director Notifications and Blocking Tasks Messages : Extension
   
Extension
An extension is a script or an application with capabilities to:
*Subscribe to an AMQP queue for receiving new messages.
*Triage the received messages.
*Process messages into operations (internal or external calls).
*Call vCloud Director API back for getting more information on the objects involved in an operation and taking action on blocked task.