Unable to publish SessionDestroyedEvent

[zeronone]

I am currently using 1.3.2 and gettings warnings logged from here.

I also found that 2.0 and 1.3.2 handles it differently. Is there any reason?
1.3.2 (here)
2.0.0 (here).

[vpavic]

Thanks for the report @zeronone.

You might want to take a look at #499 for more background on the problem and this issue effectively duplicates it, since you're using Spring Session 1.x.

Regarding the difference in handling between the 1.x and 2.x, the missing return statement in 1.x does indeed seem fishy. Can you tell me is the logged warning followed by a NullPointerException in your case?

[zeronone]

Yes, the warning is followed by an NullPointerException caused here.

Also I had one question, we have a multiple instance setup all of which uses the same Redis server. AFAIK, there is a cron job that deletes the expired session. Wouldn't deleting/expiring the session from one instance causes a notification to be triggered and delivered to other instances? If it is possible, what would be the best practice for a multi-instance setup.

Thank you.

[vpavic]

Thanks for the quick follow-up @zeronone, the NPE is a bug introduced by #984. Funny thing is, that issue was intended to address a NPE reported in #499 by handling the NPE and improving the logging, but it ended up introducing NPE in a different place. I've opened #1049 to track that.

BTW if you can provide us with a sample and instructions how to reproduce the sequence of actions which lead to this situation, please follow up on #499 as that would be of great help. I'm going to close this one as duplicate.

Regarding the question on events and multiple nodes - that's exactly the point, the HttpSessionEvent should be observed on all instances of the app that form a cluster. At that point, it's up to your app to decide what to do in event listener. Note that for SessionRepository implementations that use data stores which don't have capabilities to support cluster-wide propagation of session events, such as JdbcOperationsSessionRepository, we don't support event publishing.

Duplicate of #499