/*
Copyright 2017 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 storage

import (
	"fmt"
	"time"

	. "github.com/onsi/ginkgo"
	. "github.com/onsi/gomega"

	"k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/util/wait"
	clientset "k8s.io/client-go/kubernetes"
	kubeletmetrics "k8s.io/kubernetes/pkg/kubelet/metrics"
	"k8s.io/kubernetes/test/e2e/framework"
	"k8s.io/kubernetes/test/e2e/framework/metrics"
)

// This test needs to run in serial because other tests could interfere
// with metrics being tested here.
var _ = SIGDescribe("[Serial] Volume metrics", func() {
	var (
		c              clientset.Interface
		ns             string
		pvc            *v1.PersistentVolumeClaim
		metricsGrabber *metrics.MetricsGrabber
	)
	f := framework.NewDefaultFramework("pv")

	BeforeEach(func() {
		c = f.ClientSet
		ns = f.Namespace.Name
		framework.SkipUnlessProviderIs("gce", "gke", "aws")
		defaultScName := getDefaultStorageClassName(c)
		verifyDefaultStorageClass(c, defaultScName, true)

		test := storageClassTest{
			name:      "default",
			claimSize: "2Gi",
		}

		pvc = newClaim(test, ns, "default")
		var err error
		metricsGrabber, err = metrics.NewMetricsGrabber(c, nil, true, false, true, false, false)

		if err != nil {
			framework.Failf("Error creating metrics grabber : %v", err)
		}
	})

	AfterEach(func() {
		framework.DeletePersistentVolumeClaim(c, pvc.Name, pvc.Namespace)
	})

	It("should create prometheus metrics for volume provisioning and attach/detach", func() {
		var err error

		if !metricsGrabber.HasRegisteredMaster() {
			framework.Skipf("Environment does not support getting controller-manager metrics - skipping")
		}

		controllerMetrics, err := metricsGrabber.GrabFromControllerManager()

		Expect(err).NotTo(HaveOccurred(), "Error getting c-m metrics : %v", err)

		storageOpMetrics := getControllerStorageMetrics(controllerMetrics)

		pvc, err = c.CoreV1().PersistentVolumeClaims(pvc.Namespace).Create(pvc)
		Expect(err).NotTo(HaveOccurred())
		Expect(pvc).ToNot(Equal(nil))

		claims := []*v1.PersistentVolumeClaim{pvc}

		pod := framework.MakePod(ns, nil, claims, false, "")
		pod, err = c.CoreV1().Pods(ns).Create(pod)
		Expect(err).NotTo(HaveOccurred())

		err = framework.WaitForPodRunningInNamespace(c, pod)
		framework.ExpectNoError(framework.WaitForPodRunningInNamespace(c, pod), "Error starting pod ", pod.Name)

		framework.Logf("Deleting pod %q/%q", pod.Namespace, pod.Name)
		framework.ExpectNoError(framework.DeletePodWithWait(f, c, pod))

		updatedStorageMetrics := waitForDetachAndGrabMetrics(storageOpMetrics, metricsGrabber)

		Expect(len(updatedStorageMetrics)).ToNot(Equal(0), "Error fetching c-m updated storage metrics")

		volumeOperations := []string{"volume_provision", "volume_detach", "volume_attach"}

		for _, volumeOp := range volumeOperations {
			verifyMetricCount(storageOpMetrics, updatedStorageMetrics, volumeOp)
		}
	})

	It("should create volume metrics with the correct PVC ref", func() {
		var err error
		pvc, err = c.CoreV1().PersistentVolumeClaims(pvc.Namespace).Create(pvc)
		Expect(err).NotTo(HaveOccurred())
		Expect(pvc).ToNot(Equal(nil))

		claims := []*v1.PersistentVolumeClaim{pvc}
		pod := framework.MakePod(ns, nil, claims, false, "")
		pod, err = c.CoreV1().Pods(ns).Create(pod)
		Expect(err).NotTo(HaveOccurred())

		err = framework.WaitForPodRunningInNamespace(c, pod)
		framework.ExpectNoError(framework.WaitForPodRunningInNamespace(c, pod), "Error starting pod ", pod.Name)

		pod, err = c.CoreV1().Pods(ns).Get(pod.Name, metav1.GetOptions{})
		Expect(err).NotTo(HaveOccurred())

		// Verify volume stat metrics were collected for the referenced PVC
		volumeStatKeys := []string{
			kubeletmetrics.VolumeStatsUsedBytesKey,
			kubeletmetrics.VolumeStatsCapacityBytesKey,
			kubeletmetrics.VolumeStatsAvailableBytesKey,
			kubeletmetrics.VolumeStatsUsedBytesKey,
			kubeletmetrics.VolumeStatsInodesFreeKey,
			kubeletmetrics.VolumeStatsInodesUsedKey,
		}
		// Poll kubelet metrics waiting for the volume to be picked up
		// by the volume stats collector
		var kubeMetrics metrics.KubeletMetrics
		waitErr := wait.Poll(30*time.Second, 5*time.Minute, func() (bool, error) {
			framework.Logf("Grabbing Kubelet metrics")
			// Grab kubelet metrics from the node the pod was scheduled on
			var err error
			kubeMetrics, err = metricsGrabber.GrabFromKubelet(pod.Spec.NodeName)
			if err != nil {
				framework.Logf("Error fetching kubelet metrics")
				return false, err
			}
			key := volumeStatKeys[0]
			kubeletKeyName := fmt.Sprintf("%s_%s", kubeletmetrics.KubeletSubsystem, key)
			if !findVolumeStatMetric(kubeletKeyName, pvc.Namespace, pvc.Name, kubeMetrics) {
				return false, nil
			}
			return true, nil
		})
		Expect(waitErr).NotTo(HaveOccurred(), "Error finding volume metrics : %v", waitErr)

		for _, key := range volumeStatKeys {
			kubeletKeyName := fmt.Sprintf("%s_%s", kubeletmetrics.KubeletSubsystem, key)
			found := findVolumeStatMetric(kubeletKeyName, pvc.Namespace, pvc.Name, kubeMetrics)
			Expect(found).To(BeTrue(), "PVC %s, Namespace %s not found for %s", pvc.Name, pvc.Namespace, kubeletKeyName)
		}

		framework.Logf("Deleting pod %q/%q", pod.Namespace, pod.Name)
		framework.ExpectNoError(framework.DeletePodWithWait(f, c, pod))
	})
})

func waitForDetachAndGrabMetrics(oldMetrics map[string]int64, metricsGrabber *metrics.MetricsGrabber) map[string]int64 {
	backoff := wait.Backoff{
		Duration: 10 * time.Second,
		Factor:   1.2,
		Steps:    21,
	}

	updatedStorageMetrics := make(map[string]int64)
	oldDetachCount, ok := oldMetrics["volume_detach"]
	if !ok {
		oldDetachCount = 0
	}

	verifyMetricFunc := func() (bool, error) {
		updatedMetrics, err := metricsGrabber.GrabFromControllerManager()

		if err != nil {
			framework.Logf("Error fetching controller-manager metrics")
			return false, err
		}

		updatedStorageMetrics = getControllerStorageMetrics(updatedMetrics)
		newDetachCount, ok := updatedStorageMetrics["volume_detach"]

		// if detach metrics are not yet there, we need to retry
		if !ok {
			return false, nil
		}

		// if old Detach count is more or equal to new detach count, that means detach
		// event has not been observed yet.
		if oldDetachCount >= newDetachCount {
			return false, nil
		}
		return true, nil
	}

	waitErr := wait.ExponentialBackoff(backoff, verifyMetricFunc)
	Expect(waitErr).NotTo(HaveOccurred(), "Timeout error fetching storage c-m metrics : %v", waitErr)
	return updatedStorageMetrics
}

func verifyMetricCount(oldMetrics map[string]int64, newMetrics map[string]int64, metricName string) {
	oldCount, ok := oldMetrics[metricName]
	// if metric does not exist in oldMap, it probably hasn't been emitted yet.
	if !ok {
		oldCount = 0
	}

	newCount, ok := newMetrics[metricName]
	Expect(ok).To(BeTrue(), "Error getting updated metrics for %s", metricName)
	// It appears that in a busy cluster some spurious detaches are unavoidable
	// even if the test is run serially.  We really just verify if new count
	// is greater than old count
	Expect(newCount).To(BeNumerically(">", oldCount), "New count %d should be more than old count %d for action %s", newCount, oldCount, metricName)
}

func getControllerStorageMetrics(ms metrics.ControllerManagerMetrics) map[string]int64 {
	result := make(map[string]int64)

	for method, samples := range ms {
		if method != "storage_operation_duration_seconds_count" {
			continue
		}

		for _, sample := range samples {
			count := int64(sample.Value)
			operation := string(sample.Metric["operation_name"])
			result[operation] = count
		}
	}
	return result
}

// Finds the sample in the specified metric from `KubeletMetrics` tagged with
// the specified namespace and pvc name
func findVolumeStatMetric(metricKeyName string, namespace string, pvcName string, kubeletMetrics metrics.KubeletMetrics) bool {
	found := false
	errCount := 0
	framework.Logf("Looking for sample in metric `%s` tagged with namespace `%s`, PVC `%s`", metricKeyName, namespace, pvcName)
	if samples, ok := kubeletMetrics[metricKeyName]; ok {
		for _, sample := range samples {
			framework.Logf("Found sample %s", sample.String())
			samplePVC, ok := sample.Metric["persistentvolumeclaim"]
			if !ok {
				framework.Logf("Error getting pvc for metric %s, sample %s", metricKeyName, sample.String())
				errCount++
			}
			sampleNS, ok := sample.Metric["namespace"]
			if !ok {
				framework.Logf("Error getting namespace for metric %s, sample %s", metricKeyName, sample.String())
				errCount++
			}

			if string(samplePVC) == pvcName && string(sampleNS) == namespace {
				found = true
				break
			}
		}
	}
	Expect(errCount).To(Equal(0), "Found invalid samples")
	return found
}