[CURATOR-164] curator-x-discovery: unregisterService is not guaranteed to remove the service, due to reconnectListener concurrency issue

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 2.7.0
• Fix Version/s: 2.8.0
• Component/s: Framework
• Assignee: Jordan Zimmerman
• Reporter: Rasmus Berg Palm
• Created: 11/Nov/14 09:48
• Updated: 17/May/23 11:23
• Resolved: 27/Apr/15 22:10

Description

In ServiceDiscoveryImpl:
When unregistering a service, the reconnect listener might fire while deleting the path.
This can cause a condition where the delete finishes successfully, the service is removed from services, and then the reRegisterServices completes successfully and the service is added back in ZK and in services, end result being that the service was not removed, even though unregisterService did not throw any exceptions.

Essentially the use of the internal 'services' cache makes for a nightmare of concurrency issues. I put this as critical as the library it's really not usable IMO.

Issue Links

• fixes: CURATOR-146 discovery: registration of wrong/old service instance on RECONNECT