VPA: refactor in-place and eviction logic

This commit refactors inplace logic outside of the pods eviction restriction and separates them into their own files.
Also this commit adds PatchResourceTarget to calculators to allow them to explictly specify to the caller which
resource/subresource they should be patched to. This commit also creates a utils subpackage in order to prevent
dependency cycles in the unit tests, and adds various unit tests. Lastly, this commit adds a rateLimiter specifically
for limiting inPlaceResize API calls.

Signed-off-by: Max Cao <[email protected]>

Author: maxcao13

vertical-pod-autoscaler/pkg/admission-controller/resource/pod/handler_test.go

@@ -54,6 +54,10 @@ type fakePatchCalculator struct {
 	err     error
 }
 
+func (*fakePatchCalculator) PatchResourceTarget() patch.PatchResourceTarget {
+	return patch.Pod
+}
+
 func (c *fakePatchCalculator) CalculatePatches(_ *apiv1.Pod, _ *vpa_types.VerticalPodAutoscaler) (
 	[]resource_admission.PatchRecord, error) {
 	return c.patches, c.err

vertical-pod-autoscaler/pkg/admission-controller/resource/pod/patch/calculator.go

@@ -23,7 +23,22 @@ import (
 	vpa_types "k8s.io/autoscaler/vertical-pod-autoscaler/pkg/apis/autoscaling.k8s.io/v1"
 )
 
+// PatchResourceTarget is the type of resource that can be patched.
+type PatchResourceTarget string
+
+const (
+	// Pod refers to the pod resource itself.
+	Pod PatchResourceTarget = "Pod"
+	// Resize refers to the resize subresource of the pod.
+	Resize PatchResourceTarget = "Resize"
+
+	// Future subresources can be added here.
+	//  e.g. Status PatchResourceTarget = "Status"
+)
+
 // Calculator is capable of calculating required patches for pod.
 type Calculator interface {
 	CalculatePatches(pod *core.Pod, vpa *vpa_types.VerticalPodAutoscaler) ([]resource.PatchRecord, error)
+	// PatchResourceTarget returns the resource this calculator should calculate patches for.
+	PatchResourceTarget() PatchResourceTarget
 }

vertical-pod-autoscaler/pkg/admission-controller/resource/pod/patch/observed_containers.go

@@ -31,6 +31,10 @@ func (*observedContainers) CalculatePatches(pod *core.Pod, _ *vpa_types.Vertical
 	return []resource_admission.PatchRecord{GetAddAnnotationPatch(annotations.VpaObservedContainersLabel, vpaObservedContainersValue)}, nil
 }
 
+func (*observedContainers) PatchResourceTarget() PatchResourceTarget {
+	return Pod
+}
+
 // NewObservedContainersCalculator returns calculator for
 // observed containers patches.
 func NewObservedContainersCalculator() Calculator {

vertical-pod-autoscaler/pkg/admission-controller/resource/pod/patch/resource_updates.go

@@ -46,6 +46,10 @@ func NewResourceUpdatesCalculator(recommendationProvider recommendation.Provider
 	}
 }
 
+func (*resourcesUpdatesPatchCalculator) PatchResourceTarget() PatchResourceTarget {
+	return Pod
+}
+
 func (c *resourcesUpdatesPatchCalculator) CalculatePatches(pod *core.Pod, vpa *vpa_types.VerticalPodAutoscaler) ([]resource_admission.PatchRecord, error) {
 	result := []resource_admission.PatchRecord{}