This updates the EndpointSlice controller to make use of the
EndpointSlice tracker to identify when expected changes are not present
in the cache yet. If this is detected, the controller will wait to sync
until all expected updates have been received. This should help avoid
race conditions that would result in duplicate EndpointSlices or failed
attempts to update stale EndpointSlices. To simplify this logic, this
also moves the EndpointSlice tracker from relying on resource versions
to generations.
endpointSliceTracker creates a set of resource versions for each
service, the resource versions in the set could be deleted when
endpointslices are deleted, but the set and its key in the map is never
deleted, leading to memory leak.
This patch deletes the set if the service is deleted, and stops
initializing an empty set when "read-only" methods "Has" and "Stale" are
called.
This adds a new EndpointSlice tracker to keep track of the expected resource versions of EndpointSlices associated with each Service managed by the EndpointSlice controller. This should prevent a potential race where a syncService call could happen with an incomplete view of EndpointSlices if additions or deletions hadn't fully propagated to the cache yet. Additionally, this ensures that external changes to EndpointSlices will be handled by the EndpointSlice controller.
