From 1f55c4d6809045f871d09c0ac7473b218b2899a3 Mon Sep 17 00:00:00 2001
From: Jan Chaloupka <jchaloup@redhat.com>
Date: Fri, 11 Oct 2024 17:19:49 +0200
Subject: [PATCH] node utilization: abstract pod utilization retriever

---
 pkg/descheduler/node/node.go                  | 31 +++++++++++++------
 pkg/descheduler/pod/pods.go                   |  3 ++
 .../nodeutilization/nodeutilization.go        | 10 +++++-
 3 files changed, 33 insertions(+), 11 deletions(-)

diff --git a/pkg/descheduler/node/node.go b/pkg/descheduler/node/node.go
index 2f0e58e89..976ae0a64 100644
--- a/pkg/descheduler/node/node.go
+++ b/pkg/descheduler/node/node.go
@@ -218,7 +218,12 @@ func fitsRequest(nodeIndexer podutil.GetPodsAssignedToNodeFunc, pod *v1.Pod, nod
 		resourceNames = append(resourceNames, name)
 	}
 
-	availableResources, err := nodeAvailableResources(nodeIndexer, node, resourceNames)
+	availableResources, err := nodeAvailableResources(nodeIndexer, node, resourceNames,
+		func(pod *v1.Pod) (v1.ResourceList, error) {
+			req, _ := utils.PodRequestsAndLimits(pod)
+			return req, nil
+		},
+	)
 	if err != nil {
 		return false, err
 	}
@@ -239,12 +244,15 @@ func fitsRequest(nodeIndexer podutil.GetPodsAssignedToNodeFunc, pod *v1.Pod, nod
 }
 
 // nodeAvailableResources returns resources mapped to the quanitity available on the node.
-func nodeAvailableResources(nodeIndexer podutil.GetPodsAssignedToNodeFunc, node *v1.Node, resourceNames []v1.ResourceName) (map[v1.ResourceName]*resource.Quantity, error) {
+func nodeAvailableResources(nodeIndexer podutil.GetPodsAssignedToNodeFunc, node *v1.Node, resourceNames []v1.ResourceName, podUtilization podutil.PodUtilizationFnc) (map[v1.ResourceName]*resource.Quantity, error) {
 	podsOnNode, err := podutil.ListPodsOnANode(node.Name, nodeIndexer, nil)
 	if err != nil {
 		return nil, err
 	}
-	nodeUtilization := NodeUtilization(podsOnNode, resourceNames)
+	nodeUtilization, err := NodeUtilization(podsOnNode, resourceNames, podUtilization)
+	if err != nil {
+		return nil, err
+	}
 	remainingResources := map[v1.ResourceName]*resource.Quantity{
 		v1.ResourceCPU:    resource.NewMilliQuantity(node.Status.Allocatable.Cpu().MilliValue()-nodeUtilization[v1.ResourceCPU].MilliValue(), resource.DecimalSI),
 		v1.ResourceMemory: resource.NewQuantity(node.Status.Allocatable.Memory().Value()-nodeUtilization[v1.ResourceMemory].Value(), resource.BinarySI),
@@ -265,31 +273,34 @@ func nodeAvailableResources(nodeIndexer podutil.GetPodsAssignedToNodeFunc, node
 }
 
 // NodeUtilization returns the resources requested by the given pods. Only resources supplied in the resourceNames parameter are calculated.
-func NodeUtilization(pods []*v1.Pod, resourceNames []v1.ResourceName) map[v1.ResourceName]*resource.Quantity {
-	totalReqs := map[v1.ResourceName]*resource.Quantity{
+func NodeUtilization(pods []*v1.Pod, resourceNames []v1.ResourceName, podUtilization podutil.PodUtilizationFnc) (map[v1.ResourceName]*resource.Quantity, error) {
+	totalUtilization := map[v1.ResourceName]*resource.Quantity{
 		v1.ResourceCPU:    resource.NewMilliQuantity(0, resource.DecimalSI),
 		v1.ResourceMemory: resource.NewQuantity(0, resource.BinarySI),
 		v1.ResourcePods:   resource.NewQuantity(int64(len(pods)), resource.DecimalSI),
 	}
 	for _, name := range resourceNames {
 		if !IsBasicResource(name) {
-			totalReqs[name] = resource.NewQuantity(0, resource.DecimalSI)
+			totalUtilization[name] = resource.NewQuantity(0, resource.DecimalSI)
 		}
 	}
 
 	for _, pod := range pods {
-		req, _ := utils.PodRequestsAndLimits(pod)
+		podUtil, err := podUtilization(pod)
+		if err != nil {
+			return nil, err
+		}
 		for _, name := range resourceNames {
-			quantity, ok := req[name]
+			quantity, ok := podUtil[name]
 			if ok && name != v1.ResourcePods {
 				// As Quantity.Add says: Add adds the provided y quantity to the current value. If the current value is zero,
 				// the format of the quantity will be updated to the format of y.
-				totalReqs[name].Add(quantity)
+				totalUtilization[name].Add(quantity)
 			}
 		}
 	}
 
-	return totalReqs
+	return totalUtilization, nil
 }
 
 // IsBasicResource checks if resource is basic native.
diff --git a/pkg/descheduler/pod/pods.go b/pkg/descheduler/pod/pods.go
index 1e7ef289b..1c640bcf2 100644
--- a/pkg/descheduler/pod/pods.go
+++ b/pkg/descheduler/pod/pods.go
@@ -39,6 +39,9 @@ type FilterFunc func(*v1.Pod) bool
 // as input and returns the pods that assigned to the node.
 type GetPodsAssignedToNodeFunc func(string, FilterFunc) ([]*v1.Pod, error)
 
+// PodUtilizationFnc is a function for getting pod's utilization. E.g. requested resources of utilization from metrics.
+type PodUtilizationFnc func(pod *v1.Pod) (v1.ResourceList, error)
+
 // WrapFilterFuncs wraps a set of FilterFunc in one.
 func WrapFilterFuncs(filters ...FilterFunc) FilterFunc {
 	return func(pod *v1.Pod) bool {
diff --git a/pkg/framework/plugins/nodeutilization/nodeutilization.go b/pkg/framework/plugins/nodeutilization/nodeutilization.go
index 2d75ba314..d5bd6dc8d 100644
--- a/pkg/framework/plugins/nodeutilization/nodeutilization.go
+++ b/pkg/framework/plugins/nodeutilization/nodeutilization.go
@@ -116,9 +116,17 @@ func (s *usageSnapshot) capture(nodes []*v1.Node) error {
 			continue
 		}
 
+		nodeUsage, err := nodeutil.NodeUtilization(pods, s.resourceNames, func(pod *v1.Pod) (v1.ResourceList, error) {
+			req, _ := utils.PodRequestsAndLimits(pod)
+			return req, nil
+		})
+		if err != nil {
+			return err
+		}
+
 		// store the snapshot of pods from the same (or the closest) node utilization computation
 		s._pods[node.Name] = pods
-		s._nodeUtilization[node.Name] = nodeutil.NodeUtilization(pods, s.resourceNames)
+		s._nodeUtilization[node.Name] = nodeUsage
 	}
 
 	return nil