Enhance the garbage collector to periodically refresh the resources it
monitors (via discovery) to enable custom resource definition GC.
This implementation caches Unstructured structs for any kinds not
covered by a shared informer. The existing meta-only codec only supports
compiled types; an improved codec which supports arbitrary types could
be introduced to optimize caching to store only metadata for all
non-informer types.
Allow the list of resources the garbage collector controller should
ignore to be customizable, so downstream integrators can add their own
resources to the list, if necessary.
Alter how runtime.SerializeInfo is represented to simplify negotiation
and reduce the need to allocate during negotiation. Simplify the dynamic
client's logic around negotiating type. Add more tests for media type
handling where necessary.
The GC needs to build clients based only on Resource or Kind. Hoist the
restmapper out of the controller and the clientpool, support a new
ClientForGroupVersionKind and ClientForGroupVersionResource, and use the
appropriate one in both places.
Automatic merge from submit-queue
[GarbageCollector] measure latency
First commit is #27600.
In e2e tests, I measure the average time an item spend in the eventQueue(~1.5 ms), dirtyQueue(~13ms), and orphanQueue(~37ms). There is no stress test in e2e yet, so the number may not be useful.
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Automatic merge from submit-queue
pkg/controller/garbagecollector: simplify mutexes.
pkg/controller/garbagecollector: simplified synchronization and made idiomatic.
Similar to #29598, we can rely on the zero-value construction behavior
to embed `sync.Mutex` into parent structs.
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