tests: introduce e2e suite (#422)

* mock: implement GetStatsSummary

Signed-off-by: Paulo Pires <pjpires@gmail.com>

* make: use skaffold to deploy vk

Signed-off-by: Paulo Pires <pjpires@gmail.com>

* test: add an e2e test suite

Signed-off-by: Paulo Pires <pjpires@gmail.com>

* test: add vendored code

Signed-off-by: Paulo Pires <pjpires@gmail.com>

* docs: update README.md

Signed-off-by: Paulo Pires <pjpires@gmail.com>

* ci: run e2e on circleci

Signed-off-by: Paulo Pires <pjpires@gmail.com>

* make: improve the skaffold target

Signed-off-by: Paulo Pires <pjpires@gmail.com>

* e2e: fix defer pod deletion

Signed-off-by: Paulo Pires <pjpires@gmail.com>

* e2e: improve instructions

Signed-off-by: Paulo Pires <pjpires@gmail.com>

* makefile: default shell is bash

Signed-off-by: Paulo Pires <pjpires@gmail.com>

providers/mock/mock.go

@@ -7,15 +7,18 @@ import (
 	"io"
 	"io/ioutil"
 	"log"
+	"math/rand"
 	"time"
 
 	"github.com/cpuguy83/strongerrors"
-	"github.com/virtual-kubelet/virtual-kubelet/providers"
 	"k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/client-go/tools/remotecommand"
+	stats "k8s.io/kubernetes/pkg/kubelet/apis/stats/v1alpha1"
+
+	"github.com/virtual-kubelet/virtual-kubelet/providers"
 )
 
 const (
@@ -33,6 +36,7 @@ type MockProvider struct {
 	daemonEndpointPort int32
 	pods               map[string]*v1.Pod
 	config             MockConfig
+	startTime          time.Time
 }
 
 // MockConfig contains a mock virtual-kubelet's configurable parameters.
@@ -56,6 +60,7 @@ func NewMockProvider(providerConfig, nodeName, operatingSystem string, internalI
 		daemonEndpointPort: daemonEndpointPort,
 		pods:               make(map[string]*v1.Pod),
 		config:             config,
+		startTime:          time.Now(),
 	}
 	return &provider, nil
 }
@@ -326,6 +331,80 @@ func (p *MockProvider) OperatingSystem() string {
 	return providers.OperatingSystemLinux
 }
 
+// GetStatsSummary returns dummy stats for all pods known by this provider.
+func (p *MockProvider) GetStatsSummary(ctx context.Context) (*stats.Summary, error) {
+	// Grab the current timestamp so we can report it as the time the stats were generated.
+	time := metav1.NewTime(time.Now())
+
+	// Create the Summary object that will later be populated with node and pod stats.
+	res := &stats.Summary{}
+
+	// Populate the Summary object with basic node stats.
+	res.Node = stats.NodeStats{
+		NodeName:  p.nodeName,
+		StartTime: metav1.NewTime(p.startTime),
+	}
+
+	// Populate the Summary object with dummy stats for each pod known by this provider.
+	for _, pod := range p.pods {
+		var (
+			// totalUsageNanoCores will be populated with the sum of the values of UsageNanoCores computes across all containers in the pod.
+			totalUsageNanoCores uint64
+			// totalUsageBytes will be populated with the sum of the values of UsageBytes computed across all containers in the pod.
+			totalUsageBytes uint64
+		)
+
+		// Create a PodStats object to populate with pod stats.
+		pss := stats.PodStats{
+			PodRef: stats.PodReference{
+				Name:      pod.Name,
+				Namespace: pod.Namespace,
+				UID:       string(pod.UID),
+			},
+			StartTime: pod.CreationTimestamp,
+		}
+
+		// Iterate over all containers in the current pod to compute dummy stats.
+		for _, container := range pod.Spec.Containers {
+			// Grab a dummy value to be used as the total CPU usage.
+			// The value should fit a uint32 in order to avoid overflows later on when computing pod stats.
+			dummyUsageNanoCores := uint64(rand.Uint32())
+			totalUsageNanoCores += dummyUsageNanoCores
+			// Create a dummy value to be used as the total RAM usage.
+			// The value should fit a uint32 in order to avoid overflows later on when computing pod stats.
+			dummyUsageBytes := uint64(rand.Uint32())
+			totalUsageBytes += dummyUsageBytes
+			// Append a ContainerStats object containing the dummy stats to the PodStats object.
+			pss.Containers = append(pss.Containers, stats.ContainerStats{
+				Name:      container.Name,
+				StartTime: pod.CreationTimestamp,
+				CPU: &stats.CPUStats{
+					Time:           time,
+					UsageNanoCores: &dummyUsageNanoCores,
+				},
+				Memory: &stats.MemoryStats{
+					Time:       time,
+					UsageBytes: &dummyUsageBytes,
+				},
+			})
+		}
+
+		// Populate the CPU and RAM stats for the pod and append the PodsStats object to the Summary object to be returned.
+		pss.CPU = &stats.CPUStats{
+			Time:           time,
+			UsageNanoCores: &totalUsageNanoCores,
+		}
+		pss.Memory = &stats.MemoryStats{
+			Time:       time,
+			UsageBytes: &totalUsageBytes,
+		}
+		res.Pods = append(res.Pods, pss)
+	}
+
+	// Return the dummy stats.
+	return res, nil
+}
+
 func buildKeyFromNames(namespace string, name string) (string, error) {
 	return fmt.Sprintf("%s-%s", namespace, name), nil
 }