services: fix HealthCheckingLoadBalancer.shutdown()#5887
Merged
zhangkun83 merged 4 commits intogrpc:masterfrom Jun 14, 2019
Merged
services: fix HealthCheckingLoadBalancer.shutdown()#5887zhangkun83 merged 4 commits intogrpc:masterfrom
zhangkun83 merged 4 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().
ejona86
approved these changes
Jun 14, 2019
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The issue:
HealthCheckingLoadBalancer.shutdown()callshcState.onSubchannelState(SHUTDOWN)which removes thathcStatefromhelper.hcStates. Therefore, if more than oneSubchannels are present,ConcurrentModificationExceptionwill be thrown.This is an alternative approach from #5848 that was reverted in #5875. Thanks to #5883,
HealthCheckingLoadBalancer.shutdown()no longer has to fakeSHUTDOWNnotifications, and can completely rely onSubchannels' realSHUTDOWNnotifications for triggering the clean-up.