Programmatically remove registered instance from Eureka Server

Question

Is there a way to remove a registered instance from the Eureka Server without using REST operations? Which is the data structure that contains all the applications?

(It's clear that I want to remove them writing code in the Eureka Server).

Answer 1

The functionality you are after is available via the InstanceRegistry, which is itself just an extension of the Netflix Eureka classes (PeerAwareInstanceRegistryImpl, and AbstractInstanceRegistry).

Specifically, the AbstractInstanceRegistry#cancel(String,String,boolean) method should remove applications from the registry.

The Javadoc for this method states:

/**
 * Cancels the registration of an instance.
 *
 * <p>
 * This is normally invoked by a client when it shuts down informing the
 * server to remove the instance from traffic.
 * </p>
 *
 * @param appName the application name of the application.
 * @param id the unique identifier of the instance.
 * @param isReplication true if this is a replication event from other nodes, false
 *                      otherwise.
 * @return true if the instance was removed from the {@link AbstractInstanceRegistry} successfully, false otherwise.
 */

This is how you would achieve this from the Eureka server itself.