// replenishQuota is a replenishment function invoked by a controller to notify that a quota should be recalculated
func (rq *ResourceQuotaController) replenishQuota(groupKind unversioned.GroupKind, namespace string, object runtime.Object) {
	// check if the quota controller can evaluate this kind, if not, ignore it altogether...
	evaluators := rq.registry.Evaluators()
	evaluator, found := evaluators[groupKind]
	if !found {
		return
	}

	// check if this namespace even has a quota...
	indexKey := &api.ResourceQuota{}
	indexKey.Namespace = namespace
	resourceQuotas, err := rq.rqIndexer.Index("namespace", indexKey)
	if err != nil {
		glog.Errorf("quota controller could not find ResourceQuota associated with namespace: %s, could take up to %v before a quota replenishes", namespace, rq.resyncPeriod())
	}
	if len(resourceQuotas) == 0 {
		return
	}

	// only queue those quotas that are tracking a resource associated with this kind.
	matchedResources := evaluator.MatchesResources()
	for i := range resourceQuotas {
		resourceQuota := resourceQuotas[i].(*api.ResourceQuota)
		resourceQuotaResources := quota.ResourceNames(resourceQuota.Status.Hard)
		if len(quota.Intersection(matchedResources, resourceQuotaResources)) > 0 {
			// TODO: make this support targeted replenishment to a specific kind, right now it does a full recalc on that quota.
			rq.enqueueResourceQuota(resourceQuota)
		}
	}
}
// syncResourceQuota runs a complete sync of resource quota status across all known kinds
func (rq *ResourceQuotaController) syncResourceQuota(resourceQuota api.ResourceQuota) (err error) {
	// quota is dirty if any part of spec hard limits differs from the status hard limits
	dirty := !api.Semantic.DeepEqual(resourceQuota.Spec.Hard, resourceQuota.Status.Hard)

	// dirty tracks if the usage status differs from the previous sync,
	// if so, we send a new usage with latest status
	// if this is our first sync, it will be dirty by default, since we need track usage
	dirty = dirty || (resourceQuota.Status.Hard == nil || resourceQuota.Status.Used == nil)

	// Create a usage object that is based on the quota resource version that will handle updates
	// by default, we preserve the past usage observation, and set hard to the current spec
	previousUsed := api.ResourceList{}
	if resourceQuota.Status.Used != nil {
		previousUsed = quota.Add(api.ResourceList{}, resourceQuota.Status.Used)
	}
	usage := api.ResourceQuota{
		ObjectMeta: api.ObjectMeta{
			Name:            resourceQuota.Name,
			Namespace:       resourceQuota.Namespace,
			ResourceVersion: resourceQuota.ResourceVersion,
			Labels:          resourceQuota.Labels,
			Annotations:     resourceQuota.Annotations},
		Status: api.ResourceQuotaStatus{
			Hard: quota.Add(api.ResourceList{}, resourceQuota.Spec.Hard),
			Used: previousUsed,
		},
	}

	// find the intersection between the hard resources on the quota
	// and the resources this controller can track to know what we can
	// look to measure updated usage stats for
	hardResources := quota.ResourceNames(usage.Status.Hard)
	potentialResources := []api.ResourceName{}
	evaluators := rq.registry.Evaluators()
	for _, evaluator := range evaluators {
		potentialResources = append(potentialResources, evaluator.MatchesResources()...)
	}
	matchedResources := quota.Intersection(hardResources, potentialResources)

	// sum the observed usage from each evaluator
	newUsage := api.ResourceList{}
	usageStatsOptions := quota.UsageStatsOptions{Namespace: resourceQuota.Namespace, Scopes: resourceQuota.Spec.Scopes}
	for _, evaluator := range evaluators {
		stats, err := evaluator.UsageStats(usageStatsOptions)
		if err != nil {
			return err
		}
		newUsage = quota.Add(newUsage, stats.Used)
	}

	// mask the observed usage to only the set of resources tracked by this quota
	// merge our observed usage with the quota usage status
	// if the new usage is different than the last usage, we will need to do an update
	newUsage = quota.Mask(newUsage, matchedResources)
	for key, value := range newUsage {
		usage.Status.Used[key] = value
	}

	dirty = dirty || !quota.Equals(usage.Status.Used, resourceQuota.Status.Used)

	// there was a change observed by this controller that requires we update quota
	if dirty {
		_, err = rq.kubeClient.Core().ResourceQuotas(usage.Namespace).UpdateStatus(&usage)
		return err
	}
	return nil
}