services: fix HealthCheckingLoadBalancer.shutdown().#5848
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zhangkun83 merged 2 commits intogrpc:masterfrom Jun 7, 2019
Merged
services: fix HealthCheckingLoadBalancer.shutdown().#5848zhangkun83 merged 2 commits intogrpc:masterfrom
zhangkun83 merged 2 commits intogrpc:masterfrom
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HealthCheckingLoadBalancer.shutdown() calls hcState.onSubchannelState(SHUTDOWN) which removes that hcState from helper.hcStates. Therefore, if more than one Subchannels are present, ConcurrentModificationException will be thrown. Since HealthCheckingLoadBalancer.shutdown() will clear the hcStates set after the loop, it's unnecessary to do the deletion within the loop. However, when a Subchannel is shutdown by LoadBalancer, its HcState still needs to be removed. To do that, change moves the deletion to Subchannel.shutdown().
dapengzhang0
reviewed
Jun 7, 2019
| @Override | ||
| public void shutdown() { | ||
| helperImpl.getSynchronizationContext().throwIfNotInThisSynchronizationContext(); | ||
| helperImpl.hcStates.remove(hcState); |
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No need to call delegate.shutdown()?
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Good catch. Fixed.
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|
I would also make the similar change for Update: |
dapengzhang0
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Jun 7, 2019
ejona86
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…)" This reverts commit c6f1516. It broke an internal health checking test because the server wouldn't shut down. We assume the health checking RPC isn't getting closed.
ejona86
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This reverts commit c6f1516. It broke an internal health checking test because the server wouldn't shut down. We assume the health checking RPC isn't getting closed.
zhangkun83
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HealthCheckingLoadBalancer.shutdown() calls hcState.onSubchannelState(SHUTDOWN) which removes that hcState from helper.hcStates. Therefore, if more than one Subchannels are present, ConcurrentModificationException will be thrown. Since HealthCheckingLoadBalancer.shutdown() will clear the hcStates set after the loop, it's unnecessary to do the deletion within the loop. However, when a Subchannel is shutdown by LoadBalancer, its HcState still needs to be removed. To do that, change moves the deletion to Subchannel.shutdown().
zhangkun83
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Jun 14, 2019
The issue: HealthCheckingLoadBalancer.shutdown() calls hcState.onSubchannelState(SHUTDOWN) which removes that hcState from helper.hcStates. Therefore, if more than one Subchannels are present, ConcurrentModificationException will be thrown. This is an alternative approach from #5848 that was reverted in #5875. Thanks to #5883, HealthCheckingLoadBalancer.shutdown() no longer has to fake SHUTDOWN notifications, and can completely rely on Subchannels' real SHUTDOWN notifications for triggering the clean-up.
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HealthCheckingLoadBalancer.shutdown() calls
hcState.onSubchannelState(SHUTDOWN) which removes that hcState from
helper.hcStates. Therefore, if more than one Subchannels are present,
ConcurrentModificationException will be thrown.
Since HealthCheckingLoadBalancer.shutdown() will clear the hcStates
set after the loop, it's unnecessary to do the deletion within the
loop. However, when a Subchannel is shutdown by LoadBalancer, its
HcState still needs to be removed. To do that, change moves the
deletion to Subchannel.shutdown().