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https://issues.apache.org/jira/browse/BROOKLYN-345?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16004358#comment-16004358
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Aled Sage commented on BROOKLYN-345:
------------------------------------
Note that we may still see this exception with the latest Brooklyn if trying to
rebind to persisted state generated with 0.9.0 or older.
In 0.10.0, we fixed the persistence to include the dynamically added config
keys.
For example, with 0.9.0 a persisted catalog item
docker-engine-with-resilience_2.1.0-20161208.1801 declares:
{noformat}
brooklyn.parameters:
- name: docker.recovery.stabilizationDelay
label: "Stabilization Delay"
description: |
Time period for which the service must be consistently in the same
state to trigger an action.
Should be long enough that a restart will not trigger failure
type: org.apache.brooklyn.util.time.Duration
default: 5m
{noformat}
and:
{noformat}
brooklyn.enrichers:
- type: org.apache.brooklyn.policy.ha.ServiceFailureDetector
brooklyn.config:
serviceOnFire.stabilizationDelay:
$brooklyn:config("docker.recovery.stabilizationDelay")
{noformat}
But the entity (kv1zwls75t) did not persist that config key, so doesn't know
the default value! In this example, after rebind, it evaluates
{{$brooklyn:config("docker.recovery.stabilizationDelay")}}, which returns null.
Before rebind, it correctly returned the config key's default value.
> NPE on rebind of enricher ServiceStateLogic$ComputeServiceState
> ---------------------------------------------------------------
>
> Key: BROOKLYN-345
> URL: https://issues.apache.org/jira/browse/BROOKLYN-345
> Project: Brooklyn
> Issue Type: Bug
> Reporter: Aled Sage
> Fix For: 0.10.0
>
>
> Using Brooklyn 0.10.0-SNAPSHOT (e.g. brooklyn-server commit 66b9b1c)...
> When rebinding to existing persisted state, it failed to create the enricher
> {{ServiceStateLogic$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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