Prevent race condition when cluster is being initialized #104
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A race condition can occur between the cluster start and cluster event listeners being registered with the cluster, causing the listeners to miss events that are sent before the listener registers. This commit is a first clunky attempt at fixing this problem. It registers the listeners prior to the cluster being started. It then blocks processing of event handling until the cluster is initialized. However, some of this blocking prevents the cluster from initializing, which is why some selected events are mostly ignored. It's all rather clunky, but it seems to work. I'm committing this as a first working solution, to be improved on further.
…ution This builds on the fix to resolve a cluster event listener race, as introduced by the previous commit. In the previous commit, event handling is blocked until the cluster is fully initialized. A chicken/egg problem (where blockage of certain events prevented the cluster to initialize) caused a haphazardous implementation in which some selected events were _not_ blocked. In this commit, events are queued rather than blocked. This allows the cluster to initialize, without 'special treatment' of certain events.
GregDThomas
reviewed
Nov 3, 2024
src/java/org/jivesoftware/openfire/plugin/util/cache/ClusterListener.java
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src/java/org/jivesoftware/openfire/plugin/util/cache/ClusterListener.java
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Feedback from @viv on this was: "looks reasonable" - with that', I'll merge as-is. |
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The existing implementation suffers from a race condition that is described in #103.
This PR provides fixes in the first two commits:
Each commit has a commit message that describes the changes made in that commit.
Upon merge, these commits should possibly be squashed. I left them unsquashed for your reviewing pleasure.
Initial tests are promising, but more testing is needed. I'm creating this PR mainly because I've got a nagging feeling that there's room for improvement, that I can't quite put my finger on. I'm hoping for reviewing feedback. :)