karmada/pkg/util/resource.go

/*
Copyright 2021 The Karmada Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package util

import (
	"math"

	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/resource"

	"github.com/karmada-io/karmada/pkg/util/lifted"
)

// Resource is a collection of compute resource.
type Resource struct {
	MilliCPU         int64
	Memory           int64
	EphemeralStorage int64
	AllowedPodNumber int64

	// ScalarResources
	ScalarResources map[corev1.ResourceName]int64
}

// EmptyResource creates an empty resource object and returns.
func EmptyResource() *Resource {
	return &Resource{}
}

// NewResource creates a new resource object from resource list.
func NewResource(rl corev1.ResourceList) *Resource {
	r := &Resource{}
	r.Add(rl)
	return r
}

// Add is used to add two resources.
func (r *Resource) Add(rl corev1.ResourceList) {
	if r == nil {
		return
	}

	for rName, rQuant := range rl {
		switch rName {
		case corev1.ResourceCPU:
			r.MilliCPU += rQuant.MilliValue()
		case corev1.ResourceMemory:
			r.Memory += rQuant.Value()
		case corev1.ResourcePods:
			r.AllowedPodNumber += rQuant.Value()
		case corev1.ResourceEphemeralStorage:
			r.EphemeralStorage += rQuant.Value()
		default:
			if lifted.IsScalarResourceName(rName) {
				r.AddScalar(rName, rQuant.Value())
			}
		}
	}
}

// SubResource is used to subtract two resources, if r < rr, set r to zero.
func (r *Resource) SubResource(rr *Resource) *Resource {
	if r == nil || rr == nil {
		return r
	}

	r.MilliCPU = MaxInt64(r.MilliCPU-rr.MilliCPU, 0)
	r.Memory = MaxInt64(r.Memory-rr.Memory, 0)
	r.EphemeralStorage = MaxInt64(r.EphemeralStorage-rr.EphemeralStorage, 0)
	r.AllowedPodNumber = MaxInt64(r.AllowedPodNumber-rr.AllowedPodNumber, 0)

	for rrName, rrScalar := range rr.ScalarResources {
		if lifted.IsScalarResourceName(rrName) {
			rScalar, ok := r.ScalarResources[rrName]
			if ok {
				r.ScalarResources[rrName] = MaxInt64(rScalar-rrScalar, 0)
			}
		}
	}
	return r
}

// SetMaxResource compares with ResourceList and takes max value for each Resource.
func (r *Resource) SetMaxResource(rl corev1.ResourceList) {
	if r == nil {
		return
	}

	for rName, rQuant := range rl {
		switch rName {
		case corev1.ResourceCPU:
			if cpu := rQuant.MilliValue(); cpu > r.MilliCPU {
				r.MilliCPU = cpu
			}
		case corev1.ResourceMemory:
			if mem := rQuant.Value(); mem > r.Memory {
				r.Memory = mem
			}
		case corev1.ResourceEphemeralStorage:
			if ephemeralStorage := rQuant.Value(); ephemeralStorage > r.EphemeralStorage {
				r.EphemeralStorage = ephemeralStorage
			}
		case corev1.ResourcePods:
			if pods := rQuant.Value(); pods > r.AllowedPodNumber {
				r.AllowedPodNumber = pods
			}
		default:
			if lifted.IsScalarResourceName(rName) {
				if value := rQuant.Value(); value > r.ScalarResources[rName] {
					r.SetScalar(rName, value)
				}
			}
		}
	}
}

// AddScalar adds a resource by a scalar value of this resource.
func (r *Resource) AddScalar(name corev1.ResourceName, quantity int64) {
	r.SetScalar(name, r.ScalarResources[name]+quantity)
}

// SetScalar sets a resource by a scalar value of this resource.
func (r *Resource) SetScalar(name corev1.ResourceName, quantity int64) {
	// Lazily allocate scalar resource map.
	if r.ScalarResources == nil {
		r.ScalarResources = map[corev1.ResourceName]int64{}
	}
	r.ScalarResources[name] = quantity
}

// ResourceList returns a resource list of this resource.
func (r *Resource) ResourceList() corev1.ResourceList {
	result := corev1.ResourceList{}
	if r.MilliCPU > 0 {
		result[corev1.ResourceCPU] = *resource.NewMilliQuantity(r.MilliCPU, resource.DecimalSI)
	}
	if r.Memory > 0 {
		result[corev1.ResourceMemory] = *resource.NewQuantity(r.Memory, resource.BinarySI)
	}
	if r.EphemeralStorage > 0 {
		result[corev1.ResourceEphemeralStorage] = *resource.NewQuantity(r.EphemeralStorage, resource.BinarySI)
	}
	if r.AllowedPodNumber > 0 {
		result[corev1.ResourcePods] = *resource.NewQuantity(r.AllowedPodNumber, resource.DecimalSI)
	}
	for rName, rQuant := range r.ScalarResources {
		if rQuant > 0 {
			if lifted.IsHugePageResourceName(rName) {
				result[rName] = *resource.NewQuantity(rQuant, resource.BinarySI)
			} else {
				result[rName] = *resource.NewQuantity(rQuant, resource.DecimalSI)
			}
		}
	}
	if len(result) == 0 {
		return nil
	}
	return result
}

// MaxDivided returns how many replicas that the resource can be divided.
func (r *Resource) MaxDivided(rl corev1.ResourceList) int64 {
	res := int64(math.MaxInt64)
	for rName, rQuant := range rl {
		switch rName {
		case corev1.ResourceCPU:
			if cpu := rQuant.MilliValue(); cpu > 0 {
				res = MinInt64(res, r.MilliCPU/cpu)
			}
		case corev1.ResourceMemory:
			if mem := rQuant.Value(); mem > 0 {
				res = MinInt64(res, r.Memory/mem)
			}
		case corev1.ResourceEphemeralStorage:
			if ephemeralStorage := rQuant.Value(); ephemeralStorage > 0 {
				res = MinInt64(res, r.EphemeralStorage/ephemeralStorage)
			}
		default:
			if lifted.IsScalarResourceName(rName) {
				rScalar := r.ScalarResources[rName]
				if scalar := rQuant.Value(); scalar > 0 {
					res = MinInt64(res, rScalar/scalar)
				}
			}
		}
	}
	res = MinInt64(res, r.AllowedPodNumber)
	return res
}

// AddPodTemplateRequest add the effective request resource of a pod template to the origin resource.
// If pod container limits are specified, but requests are not, default requests to limits.
// The code logic is almost the same as kubernetes.
// https://github.com/kubernetes/kubernetes/blob/f7cdbe2c96cc12101226686df9e9819b4b007c5c/pkg/apis/core/v1/defaults.go#L147-L181
func (r *Resource) AddPodTemplateRequest(podSpec *corev1.PodSpec) *Resource {
	// DeepCopy first because we may modify the Resources.Requests field.
	podSpec = podSpec.DeepCopy()
	for i := range podSpec.Containers {
		// set requests to limits if requests are not specified, but limits are
		if podSpec.Containers[i].Resources.Limits != nil {
			if podSpec.Containers[i].Resources.Requests == nil {
				podSpec.Containers[i].Resources.Requests = make(corev1.ResourceList)
			}
			for key, value := range podSpec.Containers[i].Resources.Limits {
				if _, exists := podSpec.Containers[i].Resources.Requests[key]; !exists {
					podSpec.Containers[i].Resources.Requests[key] = value.DeepCopy()
				}
			}
		}
	}
	for i := range podSpec.InitContainers {
		if podSpec.InitContainers[i].Resources.Limits != nil {
			if podSpec.InitContainers[i].Resources.Requests == nil {
				podSpec.InitContainers[i].Resources.Requests = make(corev1.ResourceList)
			}
			for key, value := range podSpec.InitContainers[i].Resources.Limits {
				if _, exists := podSpec.InitContainers[i].Resources.Requests[key]; !exists {
					podSpec.InitContainers[i].Resources.Requests[key] = value.DeepCopy()
				}
			}
		}
	}
	return r.AddPodRequest(podSpec)
}

// AddPodRequest add the effective request resource of a pod to the origin resource.
// The Pod's effective request is the higher of:
// - the sum of all app containers(spec.Containers) request for a resource.
// - the effective init containers(spec.InitContainers) request for a resource.
// The effective init containers request is the highest request on all init containers.
func (r *Resource) AddPodRequest(podSpec *corev1.PodSpec) *Resource {
	for _, container := range podSpec.Containers {
		r.Add(container.Resources.Requests)
	}
	for _, container := range podSpec.InitContainers {
		r.SetMaxResource(container.Resources.Requests)
	}
	// If Overhead is being utilized, add to the total requests for the pod.
	// We assume the EnablePodOverhead feature gate of member cluster is set (it is on by default since 1.18).
	if podSpec.Overhead != nil {
		r.Add(podSpec.Overhead)
	}
	return r
}

// AddResourcePods adds pod resources into the Resource.
// Notice that a pod request resource list does not contain a request for pod resources,
// this function helps to add the pod resources.
func (r *Resource) AddResourcePods(pods int64) {
	r.Add(corev1.ResourceList{
		corev1.ResourcePods: *resource.NewQuantity(pods, resource.DecimalSI),
	})
}

// Clone returns a copy of this resource.
func (r *Resource) Clone() *Resource {
	if r == nil {
		return nil
	}

	res := &Resource{
		MilliCPU:         r.MilliCPU,
		Memory:           r.Memory,
		AllowedPodNumber: r.AllowedPodNumber,
		EphemeralStorage: r.EphemeralStorage,
	}
	if r.ScalarResources != nil {
		res.ScalarResources = make(map[corev1.ResourceName]int64)
		for k, v := range r.ScalarResources {
			res.ScalarResources[k] = v
		}
	}
	return res
}

// MinInt64 returns the smaller of two int64 numbers.
func MinInt64(a, b int64) int64 {
	if a <= b {
		return a
	}
	return b
}

// MaxInt64 returns the largest of two int64 numbers.
func MaxInt64(a, b int64) int64 {
	if a >= b {
		return a
	}
	return b
}