//go:build linux
// +build linux

/*
Copyright 2015 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 e2enode

import (
	"context"
	"fmt"
	"strings"
	"time"

	clientset "k8s.io/client-go/kubernetes"
	kubeletstatsv1alpha1 "k8s.io/kubelet/pkg/apis/stats/v1alpha1"
	"k8s.io/kubernetes/test/e2e/framework"
	e2ekubelet "k8s.io/kubernetes/test/e2e/framework/kubelet"
	e2eperf "k8s.io/kubernetes/test/e2e/framework/perf"
	e2epod "k8s.io/kubernetes/test/e2e/framework/pod"
	imageutils "k8s.io/kubernetes/test/utils/image"
	admissionapi "k8s.io/pod-security-admission/api"

	"github.com/onsi/ginkgo/v2"
)

var _ = SIGDescribe("Resource-usage", framework.WithSerial(), framework.WithSlow(), func() {
	const (
		// Interval to poll /stats/container on a node
		containerStatsPollingPeriod = 10 * time.Second
	)

	var (
		rc *ResourceCollector
		om *e2ekubelet.RuntimeOperationMonitor
	)

	f := framework.NewDefaultFramework("resource-usage")
	f.NamespacePodSecurityLevel = admissionapi.LevelPrivileged

	ginkgo.BeforeEach(func(ctx context.Context) {
		om = e2ekubelet.NewRuntimeOperationMonitor(ctx, f.ClientSet)
		// The test collects resource usage from a standalone Cadvisor pod.
		// The Cadvsior of Kubelet has a housekeeping interval of 10s, which is too long to
		// show the resource usage spikes. But changing its interval increases the overhead
		// of kubelet. Hence we use a Cadvisor pod.
		e2epod.NewPodClient(f).CreateSync(ctx, getCadvisorPod())
		rc = NewResourceCollector(containerStatsPollingPeriod)
	})

	ginkgo.AfterEach(func(ctx context.Context) {
		result := om.GetLatestRuntimeOperationErrorRate(ctx)
		framework.Logf("runtime operation error metrics:\n%s", e2ekubelet.FormatRuntimeOperationErrorRate(result))
	})

	// This test measures and verifies the steady resource usage of node is within limit
	// It collects data from a standalone Cadvisor with housekeeping interval 1s.
	// It verifies CPU percentiles and the lastest memory usage.
	ginkgo.Context("regular resource usage tracking", func() {
		rTests := []resourceTest{
			{
				podsNr: 10,
				cpuLimits: e2ekubelet.ContainersCPUSummary{
					kubeletstatsv1alpha1.SystemContainerKubelet: {0.50: 0.30, 0.95: 0.35},
					kubeletstatsv1alpha1.SystemContainerRuntime: {0.50: 0.30, 0.95: 0.40},
				},
				memLimits: e2ekubelet.ResourceUsagePerContainer{
					kubeletstatsv1alpha1.SystemContainerKubelet: &e2ekubelet.ContainerResourceUsage{MemoryRSSInBytes: 200 * 1024 * 1024},
					kubeletstatsv1alpha1.SystemContainerRuntime: &e2ekubelet.ContainerResourceUsage{MemoryRSSInBytes: 400 * 1024 * 1024},
				},
			},
		}

		for _, testArg := range rTests {
			itArg := testArg
			desc := fmt.Sprintf("resource tracking for %d pods per node", itArg.podsNr)
			ginkgo.It(desc, func(ctx context.Context) {
				testInfo := getTestNodeInfo(f, itArg.getTestName(), desc)

				runResourceUsageTest(ctx, f, rc, itArg)

				// Log and verify resource usage
				logAndVerifyResource(ctx, f, rc, itArg.cpuLimits, itArg.memLimits, testInfo, true)
			})
		}
	})

	ginkgo.Context("regular resource usage tracking", func() {
		rTests := []resourceTest{
			{
				podsNr: 0,
			},
			{
				podsNr: 10,
			},
			{
				podsNr: 35,
			},
			{
				podsNr: 90,
			},
		}

		for _, testArg := range rTests {
			itArg := testArg
			desc := fmt.Sprintf("resource tracking for %d pods per node [Benchmark]", itArg.podsNr)
			ginkgo.It(desc, func(ctx context.Context) {
				testInfo := getTestNodeInfo(f, itArg.getTestName(), desc)

				runResourceUsageTest(ctx, f, rc, itArg)

				// Log and verify resource usage
				logAndVerifyResource(ctx, f, rc, itArg.cpuLimits, itArg.memLimits, testInfo, false)
			})
		}
	})
})

type resourceTest struct {
	podsNr    int
	cpuLimits e2ekubelet.ContainersCPUSummary
	memLimits e2ekubelet.ResourceUsagePerContainer
}

func (rt *resourceTest) getTestName() string {
	return fmt.Sprintf("resource_%d", rt.podsNr)
}

// runResourceUsageTest runs the resource usage test
func runResourceUsageTest(ctx context.Context, f *framework.Framework, rc *ResourceCollector, testArg resourceTest) {
	const (
		// The monitoring time for one test
		monitoringTime = 10 * time.Minute
		// The periodic reporting period
		reportingPeriod = 5 * time.Minute
		// sleep for an interval here to measure steady data
		sleepAfterCreatePods = 10 * time.Second
	)
	pods := newTestPods(testArg.podsNr, true, imageutils.GetPauseImageName(), "test_pod")

	rc.Start()
	// Explicitly delete pods to prevent namespace controller cleanning up timeout
	ginkgo.DeferCleanup(deletePodsSync, f, append(pods, getCadvisorPod()))
	ginkgo.DeferCleanup(rc.Stop)

	ginkgo.By("Creating a batch of Pods")
	e2epod.NewPodClient(f).CreateBatch(ctx, pods)

	// wait for a while to let the node be steady
	time.Sleep(sleepAfterCreatePods)

	// Log once and flush the stats.
	rc.LogLatest()
	rc.Reset()

	ginkgo.By("Start monitoring resource usage")
	// Periodically dump the cpu summary until the deadline is met.
	// Note that without calling e2ekubelet.ResourceMonitor.Reset(), the stats
	// would occupy increasingly more memory. This should be fine
	// for the current test duration, but we should reclaim the
	// entries if we plan to monitor longer (e.g., 8 hours).
	deadline := time.Now().Add(monitoringTime)
	for time.Now().Before(deadline) && ctx.Err() == nil {
		timeLeft := time.Until(deadline)
		framework.Logf("Still running...%v left", timeLeft)
		if timeLeft < reportingPeriod {
			time.Sleep(timeLeft)
		} else {
			time.Sleep(reportingPeriod)
		}
		logPods(ctx, f.ClientSet)
	}

	ginkgo.By("Reporting overall resource usage")
	logPods(ctx, f.ClientSet)
}

// logAndVerifyResource prints the resource usage as perf data and verifies whether resource usage satisfies the limit.
func logAndVerifyResource(ctx context.Context, f *framework.Framework, rc *ResourceCollector, cpuLimits e2ekubelet.ContainersCPUSummary,
	memLimits e2ekubelet.ResourceUsagePerContainer, testInfo map[string]string, isVerify bool) {
	nodeName := framework.TestContext.NodeName

	// Obtain memory PerfData
	usagePerContainer, err := rc.GetLatest()
	framework.ExpectNoError(err)
	framework.Logf("%s", formatResourceUsageStats(usagePerContainer))

	usagePerNode := make(e2ekubelet.ResourceUsagePerNode)
	usagePerNode[nodeName] = usagePerContainer

	// Obtain CPU PerfData
	cpuSummary := rc.GetCPUSummary()
	framework.Logf("%s", formatCPUSummary(cpuSummary))

	cpuSummaryPerNode := make(e2ekubelet.NodesCPUSummary)
	cpuSummaryPerNode[nodeName] = cpuSummary

	// Print resource usage
	logPerfData(e2eperf.ResourceUsageToPerfDataWithLabels(usagePerNode, testInfo), "memory")
	logPerfData(e2eperf.CPUUsageToPerfDataWithLabels(cpuSummaryPerNode, testInfo), "cpu")

	// Verify resource usage
	if isVerify {
		verifyMemoryLimits(ctx, f.ClientSet, memLimits, usagePerNode)
		verifyCPULimits(cpuLimits, cpuSummaryPerNode)
	}
}

func verifyMemoryLimits(ctx context.Context, c clientset.Interface, expected e2ekubelet.ResourceUsagePerContainer, actual e2ekubelet.ResourceUsagePerNode) {
	if expected == nil {
		return
	}
	var errList []string
	for nodeName, nodeSummary := range actual {
		var nodeErrs []string
		for cName, expectedResult := range expected {
			container, ok := nodeSummary[cName]
			if !ok {
				nodeErrs = append(nodeErrs, fmt.Sprintf("container %q: missing", cName))
				continue
			}

			expectedValue := expectedResult.MemoryRSSInBytes
			actualValue := container.MemoryRSSInBytes
			if expectedValue != 0 && actualValue > expectedValue {
				nodeErrs = append(nodeErrs, fmt.Sprintf("container %q: expected RSS memory (MB) < %d; got %d",
					cName, expectedValue, actualValue))
			}
		}
		if len(nodeErrs) > 0 {
			errList = append(errList, fmt.Sprintf("node %v:\n %s", nodeName, strings.Join(nodeErrs, ", ")))
			heapStats, err := e2ekubelet.GetKubeletHeapStats(ctx, c, nodeName)
			if err != nil {
				framework.Logf("Unable to get heap stats from %q", nodeName)
			} else {
				framework.Logf("Heap stats on %q\n:%v", nodeName, heapStats)
			}
		}
	}
	if len(errList) > 0 {
		framework.Failf("Memory usage exceeding limits:\n %s", strings.Join(errList, "\n"))
	}
}

func verifyCPULimits(expected e2ekubelet.ContainersCPUSummary, actual e2ekubelet.NodesCPUSummary) {
	if expected == nil {
		return
	}
	var errList []string
	for nodeName, perNodeSummary := range actual {
		var nodeErrs []string
		for cName, expectedResult := range expected {
			perContainerSummary, ok := perNodeSummary[cName]
			if !ok {
				nodeErrs = append(nodeErrs, fmt.Sprintf("container %q: missing", cName))
				continue
			}
			for p, expectedValue := range expectedResult {
				actualValue, ok := perContainerSummary[p]
				if !ok {
					nodeErrs = append(nodeErrs, fmt.Sprintf("container %q: missing percentile %v", cName, p))
					continue
				}
				if actualValue > expectedValue {
					nodeErrs = append(nodeErrs, fmt.Sprintf("container %q: expected %.0fth%% usage < %.3f; got %.3f",
						cName, p*100, expectedValue, actualValue))
				}
			}
		}
		if len(nodeErrs) > 0 {
			errList = append(errList, fmt.Sprintf("node %v:\n %s", nodeName, strings.Join(nodeErrs, ", ")))
		}
	}
	if len(errList) > 0 {
		framework.Failf("CPU usage exceeding limits:\n %s", strings.Join(errList, "\n"))
	}
}

func logPods(ctx context.Context, c clientset.Interface) {
	nodeName := framework.TestContext.NodeName
	podList, err := e2ekubelet.GetKubeletRunningPods(ctx, c, nodeName)
	if err != nil {
		framework.Logf("Unable to retrieve kubelet pods for node %v", nodeName)
	}
	framework.Logf("%d pods are running on node %v", len(podList.Items), nodeName)
}