// limitRequestRatioConstraint enforces the limit to request ratio over the specified resource
func limitRequestRatioConstraint(limitType api.LimitType, resourceName api.ResourceName, enforced resource.Quantity, request api.ResourceList, limit api.ResourceList) error {
req, reqExists := request[resourceName]
lim, limExists := limit[resourceName]
observedReqValue, observedLimValue, _ := requestLimitEnforcedValues(req, lim, enforced)
if !reqExists || (observedReqValue == int64(0)) {
return fmt.Errorf("%s max limit to request ratio per %s is %s, but no request is specified or request is 0.", resourceName, limitType, enforced.String())
}
if !limExists || (observedLimValue == int64(0)) {
return fmt.Errorf("%s max limit to request ratio per %s is %s, but no limit is specified or limit is 0.", resourceName, limitType, enforced.String())
}
observedRatio := float64(observedLimValue) / float64(observedReqValue)
displayObservedRatio := observedRatio
maxLimitRequestRatio := float64(enforced.Value())
if enforced.Value() <= resource.MaxMilliValue {
observedRatio = observedRatio * 1000
maxLimitRequestRatio = float64(enforced.MilliValue())
}
if observedRatio > maxLimitRequestRatio {
return fmt.Errorf("%s max limit to request ratio per %s is %s, but provided ratio is %f.", resourceName, limitType, enforced.String(), displayObservedRatio)
}
return nil
}
// requestLimitEnforcedValues returns the specified values at a common precision to support comparability
func requestLimitEnforcedValues(requestQuantity, limitQuantity, enforcedQuantity resource.Quantity) (request, limit, enforced int64) {
request = requestQuantity.Value()
limit = limitQuantity.Value()
enforced = enforcedQuantity.Value()
// do a more precise comparison if possible (if the value won't overflow)
if request <= resource.MaxMilliValue && limit <= resource.MaxMilliValue && enforced <= resource.MaxMilliValue {
request = requestQuantity.MilliValue()
limit = limitQuantity.MilliValue()
enforced = enforcedQuantity.MilliValue()
}
return
}
