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https://issues.apache.org/jira/browse/DOSGI-214?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Amichai Rothman resolved DOSGI-214.
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Resolution: Fixed
Fix Version/s: 1.7.0
Assignee: Amichai Rothman (was: Christian Schneider)
Nice catch! And a good analysis too - thanks.
I made the second fix using the SimpleServiceTracker helper class though, since
it's simpler (keeps concurrency logic separate from the business logic) and I
think using synchronized as suggested would still leave a small gap between
when addingService returns and when the new service is added to the
getServiceReferences result where a new export might get lost.
> Endpoint publication to discovery does not always work
> ------------------------------------------------------
>
> Key: DOSGI-214
> URL: https://issues.apache.org/jira/browse/DOSGI-214
> Project: CXF Distributed OSGi
> Issue Type: Bug
> Components: DSW
> Affects Versions: 1.6.0
> Environment: Windows 7, Linux (OpenSuse), seems to happen more often
> with slower CPU computers
> Reporter: Timo Heinonen
> Assignee: Amichai Rothman
> Fix For: 1.7.0
>
>
> TopologyManager bundle's EndpointListenerNotifier does not call all
> EndpointListener's at all times correctly and therefore some endpoints don't
> get published to discovery (zookeeper).
> I found following problems with the current implementation:
> 1) TopologyManagerExport.exportServiceUsingRemoteServiceAdmin():
> In the end of the exportServiceUsingRemoteServiceAdmin() notifyListeners() is
> called before updating endpointregistry. This causes problem in
> EndpointListenerNotifier, because endpointRepository.getAllEndpoints() does
> not return correct state before endpoints are updated. Basically problem
> exists when ServiceTracker's addingService() is called simultaneously for
> discovery bundle's EndpointLIstener and other thread (call coming from
> TopologyManagerExport) calls notfiyListeners().
> stEndpointListeners.getServiceReferences() does not yet return the endpoint
> listener of discovery bundle and therefore discovery is not notified. Also,
> addingService() call does not find endpoint from endpointRegistry and
> therefore does not publish it.
> FIX: By changing the order of notifyListeners() and addEndpoints() in
> TopologyManagerExport the above is fixed.
> 2) EndpointListenerNotifier is not threadsafe although ServiceTracker is.
> stEndpointListeners.getServiceReferences() returns just added
> EndpointListener (the one from discovery bundle) only AFTER whole overrided
> addingService() method has finished. So following can happen:
> a) addingService() is called with discovery bundle's EPL
> b) super.addingService() call is finished and notifyListener() is called with
> no new Endpoint because TopologyManagerExport has not yet added it to
> endPointRepo
> c) TopologyManagerExport calls addEndpoint() and notifyListeners() (in fixed
> order) and EndpointListenerNotifier does not notify discove EPL, because
> addingService() call has not yet returned and therefore
> stEndpointListeners.getServiceReferences() still returns 1 EPL (from
> topologyManager bundle)
> FIX: Add synchronized (EndpointListenerNotifier.this) to both methods
> addingService and modifiedService. Also add synchronized (this) to
> notifyListeners() method so that lock guards call to
> stdEndpointListeners.getServiceReference().
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