test/e2e: add kube-proxy metrics grabber

Signed-off-by: Daman Arora <aroradaman@gmail.com>

test/e2e/framework/metrics/kube_proxy_metrics.go

@@ -0,0 +1,42 @@
+/*
+Copyright 2024 The Kubernetes 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 metrics
+
+import (
+	"k8s.io/component-base/metrics/testutil"
+)
+
+// KubeProxyMetrics is metrics for kube-proxy
+type KubeProxyMetrics testutil.Metrics
+
+// GetCounterMetricValue returns value for metric type counter.
+func (m *KubeProxyMetrics) GetCounterMetricValue(metricName string) float64 {
+	return float64(testutil.Metrics(*m)[metricName][0].Value)
+}
+
+func newKubeProxyMetricsMetrics() KubeProxyMetrics {
+	result := testutil.NewMetrics()
+	return KubeProxyMetrics(result)
+}
+
+func parseKubeProxyMetrics(data string) (KubeProxyMetrics, error) {
+	result := newKubeProxyMetricsMetrics()
+	if err := testutil.ParseMetrics(data, (*testutil.Metrics)(&result)); err != nil {
+		return KubeProxyMetrics{}, err
+	}
+	return result, nil
+}

test/e2e/framework/metrics/metrics_grabber.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"net"
 	"regexp"
+	"strconv"
 	"sync"
 	"time"
 
@@ -32,8 +33,9 @@ import (
 	clientset "k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/rest"
 	"k8s.io/klog/v2"
-
+	"k8s.io/kubernetes/test/e2e/framework"
 	e2epod "k8s.io/kubernetes/test/e2e/framework/pod"
+	e2epodoutput "k8s.io/kubernetes/test/e2e/framework/pod/output"
 )
 
 const (
@@ -43,6 +45,8 @@ const (
 	kubeControllerManagerPort = 10257
 	// snapshotControllerPort is the port for the snapshot controller
 	snapshotControllerPort = 9102
+	// kubeProxyPort is the default port for the kube-proxy status server.
+	kubeProxyPort = 10249
 )
 
 // MetricsGrabbingDisabledError is an error that is wrapped by the
@@ -233,6 +237,45 @@ func (g *Grabber) getMetricsFromNode(ctx context.Context, nodeName string, kubel
 	}
 }
 
+// GrabFromKubeProxy returns metrics from kube-proxy
+func (g *Grabber) GrabFromKubeProxy(ctx context.Context, nodeName string) (KubeProxyMetrics, error) {
+	nodes, err := g.client.CoreV1().Nodes().List(ctx, metav1.ListOptions{FieldSelector: fields.Set{"metadata.name": nodeName}.AsSelector().String()})
+	if err != nil {
+		return KubeProxyMetrics{}, err
+	}
+
+	if len(nodes.Items) != 1 {
+		return KubeProxyMetrics{}, fmt.Errorf("error listing nodes with name %v, got %v", nodeName, nodes.Items)
+	}
+	output, err := g.grabFromKubeProxy(ctx, nodeName)
+	if err != nil {
+		return KubeProxyMetrics{}, err
+	}
+	return parseKubeProxyMetrics(output)
+}
+
+func (g *Grabber) grabFromKubeProxy(ctx context.Context, nodeName string) (string, error) {
+	hostCmdPodName := fmt.Sprintf("grab-kube-proxy-metrics-%s", framework.RandomSuffix())
+	hostCmdPod := e2epod.NewExecPodSpec(metav1.NamespaceSystem, hostCmdPodName, true)
+	nodeSelection := e2epod.NodeSelection{Name: nodeName}
+	e2epod.SetNodeSelection(&hostCmdPod.Spec, nodeSelection)
+	if _, err := g.client.CoreV1().Pods(metav1.NamespaceSystem).Create(ctx, hostCmdPod, metav1.CreateOptions{}); err != nil {
+		return "", fmt.Errorf("failed to create pod to fetch metrics: %w", err)
+	}
+	if err := e2epod.WaitTimeoutForPodReadyInNamespace(ctx, g.client, hostCmdPodName, metav1.NamespaceSystem, 5*time.Minute); err != nil {
+		return "", fmt.Errorf("error waiting for pod to be up: %w", err)
+	}
+
+	host := "127.0.0.1"
+	if framework.TestContext.ClusterIsIPv6() {
+		host = "::1"
+	}
+
+	stdout, err := e2epodoutput.RunHostCmd(metav1.NamespaceSystem, hostCmdPodName, fmt.Sprintf("curl --silent %s/metrics", net.JoinHostPort(host, strconv.Itoa(kubeProxyPort))))
+	_ = g.client.CoreV1().Pods(metav1.NamespaceSystem).Delete(ctx, hostCmdPodName, metav1.DeleteOptions{})
+	return stdout, err
+}
+
 // GrabFromScheduler returns metrics from scheduler
 func (g *Grabber) GrabFromScheduler(ctx context.Context) (SchedulerMetrics, error) {
 	if !g.grabFromScheduler {