bug: fix goroutine leaks caused by incorrect usage of WatchCh
#14916
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pglass
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Oct 7, 2022
memdb's `WatchCh` method creates a goroutine that will publish to the returned channel when the watchset is triggered or the given context is canceled. Although this is called out in its godoc comment, it's not obvious that this method creates a goroutine who's lifecycle you need to manage. In the xDS capacity controller, we were calling `WatchCh` on each iteration of the control loop, meaning the number of goroutines would grow on each autopilot event until there was catalog churn. In the catalog config source, we were calling `WatchCh` with the background context, meaning that the goroutine would keep running after the sync loop had terminated.
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Description
memdb's
WatchChmethod creates a goroutine that will publish to the returned channel when the watchset is triggered or the given context is canceled. Although this is called out in its godoc comment, it's not obvious that this method creates a goroutine who's lifecycle you need to manage.In the xDS capacity controller, we were calling
WatchChon each iteration of the control loop, meaning the number of goroutines would grow on each autopilot event until there was catalog churn.In the catalog config source, we were calling
WatchChwith the background context, meaning that the goroutine would keep running after the sync loop had terminated.