Timo Heinonen created DOSGI-214:
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Summary: 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
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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