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https://issues.apache.org/jira/browse/BROOKLYN-345?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15670344#comment-15670344
]
Aled Sage commented on BROOKLYN-345:
------------------------------------
The underlying problem was actually more serious! We were not persisting
"dynamic config keys", unless they had a value. For example, if you used
{{brooklyn.parameters:}} in a yaml blueprint to give a default value, but
didn't then override that default, the persisted entity would lose the config
key when Brooklyn was restarted. Therefore the config key's default value would
no longer be available after rebind.
See the fix in https://github.com/apache/brooklyn-server/pull/440
> NPE on rebind of enricher ServiceStateLogic$ComputeServiceState
> ---------------------------------------------------------------
>
> Key: BROOKLYN-345
> URL: https://issues.apache.org/jira/browse/BROOKLYN-345
> Project: Brooklyn
> Issue Type: Bug
> Reporter: Aled Sage
>
> Using Brooklyn 0.10.0-SNAPSHOT (e.g. brooklyn-server commit 66b9b1c)...
> When rebinding to existing persisted state, it failed to create the enricher
> {{ServiceStateLogic$ComputeServiceState}} with the NPE shown below (but then
> continued, so this is otherwise benign):
> {noformat}
> 2016-09-09 09:31:03,850 WARN o.a.b.c.m.r.RebindExceptionHandlerImpl
> [brooklyn-execmanager-VtZheMDn-0]: problem adding enricher cdoy70m1hv
> (ServiceFailureDetector{name=org.apache.brooklyn.policy.ha.ServiceFailureDetector,
> uniqueTag=service.state.actual, running=true,
> entity=VanillaSoftwareProcessImpl{id=pwz8z4pbyp}, id=cdoy70m1hv}) to entity
> pwz8z4pbyp (VanillaSoftwareProcessImpl{id=pwz8z4pbyp}); continuing
> java.lang.NullPointerException: null
> at
> org.apache.brooklyn.policy.ha.ServiceFailureDetector.setActualState(ServiceFailureDetector.java:188)
> ~[brooklyn-policy-0.10.0-20160907.0931.jar:0.10.0-20160907.0931]
> at
> org.apache.brooklyn.core.entity.lifecycle.ServiceStateLogic$ComputeServiceState.onEvent(ServiceStateLogic.java:288)
> ~[brooklyn-core-0.10.0-20160907.0931.jar:0.10.0-20160907.0931]
> at
> org.apache.brooklyn.policy.ha.ServiceFailureDetector.onEvent(ServiceFailureDetector.java:159)
> ~[brooklyn-policy-0.10.0-20160907.0931.jar:0.10.0-20160907.0931]
> at
> org.apache.brooklyn.core.entity.lifecycle.ServiceStateLogic$ComputeServiceState.setEntity(ServiceStateLogic.java:274)
> ~[brooklyn-core-0.10.0-20160907.0931.jar:0.10.0-20160907.0931]
> at
> org.apache.brooklyn.core.entity.AbstractEntity$BasicEnricherSupport.add(AbstractEntity.java:1788)
> ~[brooklyn-core-0.10.0-20160907.0931.jar:0.10.0-20160907.0931]
> at
> org.apache.brooklyn.core.mgmt.rebind.BasicEntityRebindSupport.addEnrichers(BasicEntityRebindSupport.java:145)
> [brooklyn-core-0.10.0-20160907.0931.jar:0.10.0-20160907.0931]
> at
> org.apache.brooklyn.core.mgmt.rebind.BasicEntityRebindSupport.addEnrichers(BasicEntityRebindSupport.java:47)
> [brooklyn-core-0.10.0-20160907.0931.jar:0.10.0-20160907.0931]
> at
> org.apache.brooklyn.core.mgmt.rebind.RebindIteration.associateAdjunctsWithEntities(RebindIteration.java:650)
> [brooklyn-core-0.10.0-20160907.0931.jar:0.10.0-20160907.0931]
> at
> org.apache.brooklyn.core.mgmt.rebind.RebindIteration.doRun(RebindIteration.java:244)
> [brooklyn-core-0.10.0-20160907.0931.jar:0.10.0-20160907.0931]
> at
> org.apache.brooklyn.core.mgmt.rebind.InitialFullRebindIteration.doRun(InitialFullRebindIteration.java:69)
> [brooklyn-core-0.10.0-20160907.0931.jar:0.10.0-20160907.0931]
> at
> org.apache.brooklyn.core.mgmt.rebind.RebindIteration.run(RebindIteration.java:266)
> [brooklyn-core-0.10.0-20160907.0931.jar:0.10.0-20160907.0931]
> at
> org.apache.brooklyn.core.mgmt.rebind.RebindManagerImpl.rebindImpl(RebindManagerImpl.java:558)
> [brooklyn-core-0.10.0-20160907.0931.jar:0.10.0-20160907.0931]
> at
> org.apache.brooklyn.core.mgmt.rebind.RebindManagerImpl$3.call(RebindManagerImpl.java:508)
> [brooklyn-core-0.10.0-20160907.0931.jar:0.10.0-20160907.0931]
> at
> org.apache.brooklyn.core.mgmt.rebind.RebindManagerImpl$3.call(RebindManagerImpl.java:506)
> [brooklyn-core-0.10.0-20160907.0931.jar:0.10.0-20160907.0931]
> at
> org.apache.brooklyn.util.core.task.BasicExecutionManager$SubmissionCallable.call(BasicExecutionManager.java:519)
> [brooklyn-core-0.10.0-20160907.0931.jar:0.10.0-20160907.0931]
> at java.util.concurrent.FutureTask.run(FutureTask.java:262)
> [na:1.7.0_95]
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
> [na:1.7.0_95]
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
> [na:1.7.0_95]
> at java.lang.Thread.run(Thread.java:745) [na:1.7.0_95]
> {noformat}
> The line throwing the NPE is executing {{setEntityOnFireTime = now +
> getConfig(SERVICE_ON_FIRE_STABILIZATION_DELAY).toMilliseconds()}}. That
> suggests we got null for the config value, even though there is a default
> value of zero for it.
> The enricher persisted state contains:
> {noformat}
> <serviceOnFire.stabilizationDelay>
>
> <org.apache.brooklyn.camp.brooklyn.spi.dsl.methods.DslComponent_-DslConfigSupplier>
> <component>
> <componentId></componentId>
> <scope>THIS</scope>
> </component>
> <keyName>swarm.recovery.stabilizationDelay</keyName>
>
> </org.apache.brooklyn.camp.brooklyn.spi.dsl.methods.DslComponent_-DslConfigSupplier>
> </serviceOnFire.stabilizationDelay>
> {noformat}
> And the owning entity has:
> {noformat}
> brooklyn.parameters:
> - name: swarm.recovery.stabilizationDelay
> label: Stabilization Delay
> description: |
> Time period for which the service must be consistently in the same
> state to trigger an action
> # A restart shouldn't trigger failure
> type: org.apache.brooklyn.util.time.Duration
> default: 5m
> {noformat}
> There are a few things we should think about fixing:
> 1. guard against the NPE in {{ServiceFailureDetector.setActualState}} (i.e.
> handle when the config returns null) - but unclear what value it should then
> default to.
> 2. avoid calling this code on rebind. for example, instead of
> {{ComputeServiceState.setEntity}} immediately calling {{onEvent(null)}}, it
> could subscribe with "notifyOfInitialValue" so that it gets a callback (in
> the right thread, at the right time).
> 3. investigate further why the config lookup returned null - e.g. is it
> because entity wasn't fully initialised, or because the DSL didn't find the
> default value defined in brooklyn.parameters?
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