func (a *gcPermissionsEnforcement) Admit(attributes admission.Attributes) (err error) {
// if we aren't changing owner references, then the edit is always allowed
if !isChangingOwnerReference(attributes.GetObject(), attributes.GetOldObject()) {
return nil
}
deleteAttributes := authorizer.AttributesRecord{
User: attributes.GetUserInfo(),
Verb: "delete",
Namespace: attributes.GetNamespace(),
APIGroup: attributes.GetResource().Group,
APIVersion: attributes.GetResource().Version,
Resource: attributes.GetResource().Resource,
Subresource: attributes.GetSubresource(),
Name: attributes.GetName(),
ResourceRequest: true,
Path: "",
}
allowed, reason, err := a.authorizer.Authorize(deleteAttributes)
if allowed {
return nil
}
return admission.NewForbidden(attributes, fmt.Errorf("cannot set an ownerRef on a resource you can't delete: %v, %v", reason, err))
}
// checkRequest verifies that the request does not exceed any quota constraint. it returns a copy of quotas not yet persisted
// that capture what the usage would be if the request succeeded. It return an error if the is insufficient quota to satisfy the request
func (e *quotaEvaluator) checkRequest(quotas []api.ResourceQuota, a admission.Attributes) ([]api.ResourceQuota, error) {
namespace := a.GetNamespace()
evaluators := e.registry.Evaluators()
evaluator, found := evaluators[a.GetKind().GroupKind()]
if !found {
return quotas, nil
}
op := a.GetOperation()
if !evaluator.Handles(op) {
return quotas, nil
}
// find the set of quotas that are pertinent to this request
// reject if we match the quota, but usage is not calculated yet
// reject if the input object does not satisfy quota constraints
// if there are no pertinent quotas, we can just return
inputObject := a.GetObject()
interestingQuotaIndexes := []int{}
for i := range quotas {
resourceQuota := quotas[i]
match, err := evaluator.Matches(&resourceQuota, inputObject)
if err != nil {
return quotas, err
}
if !match {
continue
}
hardResources := quota.ResourceNames(resourceQuota.Status.Hard)
requiredResources := evaluator.MatchingResources(hardResources)
if err := evaluator.Constraints(requiredResources, inputObject); err != nil {
return nil, admission.NewForbidden(a, fmt.Errorf("failed quota: %s: %v", resourceQuota.Name, err))
}
if !hasUsageStats(&resourceQuota) {
return nil, admission.NewForbidden(a, fmt.Errorf("status unknown for quota: %s", resourceQuota.Name))
}
interestingQuotaIndexes = append(interestingQuotaIndexes, i)
}
if len(interestingQuotaIndexes) == 0 {
return quotas, nil
}
// Usage of some resources cannot be counted in isolation. For example, when
// the resource represents a number of unique references to external
// resource. In such a case an evaluator needs to process other objects in
// the same namespace which needs to be known.
if accessor, err := meta.Accessor(inputObject); namespace != "" && err == nil {
if accessor.GetNamespace() == "" {
accessor.SetNamespace(namespace)
}
}
// there is at least one quota that definitely matches our object
// as a result, we need to measure the usage of this object for quota
// on updates, we need to subtract the previous measured usage
// if usage shows no change, just return since it has no impact on quota
deltaUsage, err := evaluator.Usage(inputObject)
if err != nil {
return quotas, err
}
// ensure that usage for input object is never negative (this would mean a resource made a negative resource requirement)
if negativeUsage := quota.IsNegative(deltaUsage); len(negativeUsage) > 0 {
return nil, admission.NewForbidden(a, fmt.Errorf("quota usage is negative for resource(s): %s", prettyPrintResourceNames(negativeUsage)))
}
if admission.Update == op {
prevItem := a.GetOldObject()
if prevItem == nil {
return nil, admission.NewForbidden(a, fmt.Errorf("unable to get previous usage since prior version of object was not found"))
}
// if we can definitively determine that this is not a case of "create on update",
// then charge based on the delta. Otherwise, bill the maximum
metadata, err := meta.Accessor(prevItem)
if err == nil && len(metadata.GetResourceVersion()) > 0 {
prevUsage, innerErr := evaluator.Usage(prevItem)
if innerErr != nil {
return quotas, innerErr
}
deltaUsage = quota.Subtract(deltaUsage, prevUsage)
}
}
if quota.IsZero(deltaUsage) {
return quotas, nil
}
outQuotas, err := copyQuotas(quotas)
if err != nil {
return nil, err
}
for _, index := range interestingQuotaIndexes {
resourceQuota := outQuotas[index]
hardResources := quota.ResourceNames(resourceQuota.Status.Hard)
requestedUsage := quota.Mask(deltaUsage, hardResources)
newUsage := quota.Add(resourceQuota.Status.Used, requestedUsage)
maskedNewUsage := quota.Mask(newUsage, quota.ResourceNames(requestedUsage))
if allowed, exceeded := quota.LessThanOrEqual(maskedNewUsage, resourceQuota.Status.Hard); !allowed {
failedRequestedUsage := quota.Mask(requestedUsage, exceeded)
failedUsed := quota.Mask(resourceQuota.Status.Used, exceeded)
failedHard := quota.Mask(resourceQuota.Status.Hard, exceeded)
return nil, admission.NewForbidden(a,
fmt.Errorf("exceeded quota: %s, requested: %s, used: %s, limited: %s",
resourceQuota.Name,
prettyPrint(failedRequestedUsage),
prettyPrint(failedUsed),
prettyPrint(failedHard)))
}
// update to the new usage number
outQuotas[index].Status.Used = newUsage
}
return outQuotas, nil
}