[CURATOR-617] UnregisterService Method in ServiceDiscoveryImpl is non-Idempotent in case of connection-failure

The unregisterService( ) method in ServiceDiscoveryImpl throws an unhandled KeeperException.ConnectionLossException the first time it is invoked while the server connection is down. The next time, however, the service has already been removed from the internal services cache. Hence the internalUnregisterService function does not proceed since the entry is null the second time around.

We are not using the blockUntilConnected option, and instead are trying to implement a local retry mechanism. We are dependent upon the ConnectionLossException to be thrown, in order to catch and evaluate it before retrying with an exponential back-off.

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Originally reported by asingh97, imported from: UnregisterService Method in ServiceDiscoveryImpl is non-Idempotent in case of connection-failure

• assignee: randgalt
  
• status: Open
  
• priority: Major
  
• resolution: Unresolved
  
• imported: 2025-01-21
  

Start by reading ServiceDiscoveryImpl.unregisterService and internalUnregisterService, then trace how a connection-loss failure changes the internal services cache. Reproduce the first unregister attempt while the server connection is down and add coverage showing that a retry can still perform the removal after the failure.

Written by the indexing model from the issue text.