Remove global variables from kubletclient

Fixes #673

pkg/k8sclient/k8sclient.go

@@ -259,7 +259,7 @@ func getKubernetesDelegate(client *ClientInfo, net *types.NetworkSelectionElemen
 		logging.Debugf("getKubernetesDelegate: found resourceName annotation : %s", resourceName)
 
 		if resourceMap == nil {
-			ck, err := kubeletclient.GetResourceClient()
+			ck, err := kubeletclient.GetResourceClient("")
 			if err != nil {
 				return nil, resourceMap, logging.Errorf("getKubernetesDelegate: failed to get a ResourceClient instance: %v", err)
 			}

pkg/kubeletclient/kubeletclient.go

@@ -1,8 +1,8 @@
 package kubeletclient
 
 import (
+	"net/url"
 	"os"
-	"path/filepath"
 	"time"
 
 	"golang.org/x/net/context"
@@ -18,27 +18,26 @@ import (
 const (
 	defaultKubeletSocketFile   = "kubelet.sock"
 	defaultPodResourcesMaxSize = 1024 * 1024 * 16 // 16 Mb
-)
-
-var (
-	kubeletSocket           string
-	defaultPodResourcesPath = "/var/lib/kubelet/pod-resources"
+	defaultPodResourcesPath    = "/var/lib/kubelet/pod-resources"
 )
 
 // GetResourceClient returns an instance of ResourceClient interface initialized with Pod resource information
-func GetResourceClient() (types.ResourceClient, error) {
+func GetResourceClient(kubeletSocket string) (types.ResourceClient, error) {
 	// If Kubelet resource API endpoint exist use that by default
 	// Or else fallback with checkpoint file
-	if hasKubeletAPIEndpoint() {
+	if kubeletSocket == "" {
+		kubeletSocket = util.LocalEndpoint(defaultPodResourcesPath, podresources.Socket)
+	}
+	if hasKubeletAPIEndpoint(kubeletSocket) {
 		logging.Debugf("GetResourceClient: using Kubelet resource API endpoint")
-		return getKubeletClient()
+		return getKubeletClient(kubeletSocket)
 	}
 
 	logging.Debugf("GetResourceClient: using Kubelet device plugin checkpoint")
 	return checkpoint.GetCheckpoint()
 }
 
-func getKubeletClient() (types.ResourceClient, error) {
+func getKubeletClient(kubeletSocket string) (types.ResourceClient, error) {
 	newClient := &kubeletClient{}
 	if kubeletSocket == "" {
 		kubeletSocket = util.LocalEndpoint(defaultPodResourcesPath, podresources.Socket)
@@ -102,10 +101,13 @@ func (rc *kubeletClient) GetPodResourceMap(pod *v1.Pod) (map[string]*types.Resou
 	return resourceMap, nil
 }
 
-func hasKubeletAPIEndpoint() bool {
+func hasKubeletAPIEndpoint(endpoint string) bool {
+	u, err := url.Parse(endpoint)
+	if err != nil {
+		return false
+	}
 	// Check for kubelet resource API socket file
-	kubeletAPISocket := filepath.Join(defaultPodResourcesPath, defaultKubeletSocketFile)
-	if _, err := os.Stat(kubeletAPISocket); err != nil {
+	if _, err := os.Stat(u.Path); err != nil {
 		logging.Debugf("hasKubeletAPIEndpoint: error looking up kubelet resource api socket file: %q", err)
 		return false
 	}

pkg/kubeletclient/kubeletclient_test.go

@@ -63,25 +63,27 @@ func TestKubeletclient(t *testing.T) {
 	RunSpecs(t, "Kubeletclient Suite")
 }
 
+var testKubeletSocket string
 func setUp() error {
 	tempSocketDir, err := ioutil.TempDir("", "kubelet-resource-client")
 	if err != nil {
 		return err
 	}
-	defaultPodResourcesPath = filepath.Join(tempSocketDir, defaultPodResourcesPath)
+	testingPodResourcesPath := filepath.Join(tempSocketDir, defaultPodResourcesPath)
 
-	if err := os.MkdirAll(defaultPodResourcesPath, os.ModeDir); err != nil {
+	if err := os.MkdirAll(testingPodResourcesPath, os.ModeDir); err != nil {
 		return err
 	}
 
-	socketDir = defaultPodResourcesPath
+	socketDir = testingPodResourcesPath
 	socketName = filepath.Join(socketDir, "kubelet.sock")
+	testKubeletSocket = socketName
 
 	fakeServer = &fakeResourceServer{server: grpc.NewServer()}
 	podresourcesapi.RegisterPodResourcesListerServer(fakeServer.server, fakeServer)
 	lis, err := util.CreateListener(socketName)
 	if err != nil {
-		return nil
+		return err
 	}
 	go fakeServer.server.Serve(lis)
 	return nil
@@ -109,14 +111,12 @@ var _ = Describe("Kubelet resource endpoint data read operations", func() {
 
 	Context("GetResourceClient()", func() {
 		It("should return no error", func() {
-			kubeletSocket = socketName
-			_, err := GetResourceClient()
+			_, err := GetResourceClient(testKubeletSocket)
 			Expect(err).NotTo(HaveOccurred())
 		})
 
 		It("should fail with missing file", func() {
-			kubeletSocket = "sampleSocketString"
-			_, err := GetResourceClient()
+			_, err := GetResourceClient("sampleSocketString")
 			Expect(err).To(HaveOccurred())
 		})
 	})
@@ -138,37 +138,7 @@ var _ = Describe("Kubelet resource endpoint data read operations", func() {
 					},
 				},
 			}
-			kubeletSocket = socketName
-			client, err := getKubeletClient()
-			Expect(err).NotTo(HaveOccurred())
-
-			outputRMap := map[string]*mtypes.ResourceInfo{
-				"resource": &mtypes.ResourceInfo{DeviceIDs: []string{"dev0", "dev1"}},
-			}
-			resourceMap, err := client.GetPodResourceMap(fakePod)
-			Expect(err).NotTo(HaveOccurred())
-			Expect(resourceMap).ShouldNot(BeNil())
-			Expect(resourceMap).To(Equal(outputRMap))
-		})
-
-		It("should return no error with empty socket", func() {
-			podUID := k8sTypes.UID("970a395d-bb3b-11e8-89df-408d5c537d23")
-			fakePod := &v1.Pod{
-				ObjectMeta: metav1.ObjectMeta{
-					Name:      "pod-name",
-					Namespace: "pod-namespace",
-					UID:       podUID,
-				},
-				Spec: v1.PodSpec{
-					Containers: []v1.Container{
-						{
-							Name: "container-name",
-						},
-					},
-				},
-			}
-			kubeletSocket = ""
-			client, err := getKubeletClient()
+			client, err := getKubeletClient(testKubeletSocket)
 			Expect(err).NotTo(HaveOccurred())
 
 			outputRMap := map[string]*mtypes.ResourceInfo{
@@ -181,8 +151,7 @@ var _ = Describe("Kubelet resource endpoint data read operations", func() {
 		})
 
 		It("should return an error with garbage socket value", func() {
-			kubeletSocket = "/badfilepath!?//"
-			_, err := getKubeletClient()
+			_, err := getKubeletClient("/badfilepath!?//")
 			Expect(err).To(HaveOccurred())
 		})
 	})
@@ -197,8 +166,7 @@ var _ = Describe("Kubelet resource endpoint data read operations", func() {
 					UID:       podUID,
 				},
 			}
-			kubeletSocket = socketName
-			client, err := getKubeletClient()
+			client, err := getKubeletClient(testKubeletSocket)
 			Expect(err).NotTo(HaveOccurred())
 			_, err = client.GetPodResourceMap(fakePod)
 			Expect(err).To(HaveOccurred())
@@ -215,8 +183,7 @@ var _ = Describe("Kubelet resource endpoint data read operations", func() {
 					UID:       podUID,
 				},
 			}
-			kubeletSocket = socketName
-			client, err := getKubeletClient()
+			client, err := getKubeletClient(testKubeletSocket)
 			Expect(err).NotTo(HaveOccurred())
 			_, err = client.GetPodResourceMap(fakePod)
 			Expect(err).To(HaveOccurred())
@@ -234,8 +201,7 @@ var _ = Describe("Kubelet resource endpoint data read operations", func() {
 				},
 			}
 
-			kubeletSocket = socketName
-			client, err := getKubeletClient()
+			client, err := getKubeletClient(testKubeletSocket)
 			Expect(err).NotTo(HaveOccurred())
 
 			emptyRMap := map[string]*mtypes.ResourceInfo{}