Merge pull request #1720 from daixiang0/enable-goconst

Lint: enable goconst linter

9 files changed, 77 insertions, 64 deletions

diff --git a/.golangci.yml b/.golangci.yml
index 81b2a6185..88791b05b 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -45,6 +45,7 @@ linters-settings:
 linters:
   disable-all: true
   enable:
+    - goconst
     - gofmt
     - golint
     - gosimple
diff --git a/edge/pkg/devicetwin/dtmanager/twin.go b/edge/pkg/devicetwin/dtmanager/twin.go
index b3c9d536c..1e852169a 100644
--- a/edge/pkg/devicetwin/dtmanager/twin.go
+++ b/edge/pkg/devicetwin/dtmanager/twin.go
@@ -31,6 +31,8 @@ const (
 	DealActual = 1
 	//DealExpected deal exepected
 	DealExpected = 0
+
+	stringType = "string"
 )
 
 var (
@@ -505,7 +507,7 @@ func isTwinValueDiff(twin *dttype.MsgTwin, msgTwin *dttype.MsgTwin, dealType int
 	if msgTwinValue != nil {
 		hasMsgTwin = true
 	}
-	valueType := "string"
+	valueType := stringType
 	if strings.Compare(twin.Metadata.Type, "deleted") == 0 {
 		if msgTwin.Metadata != nil {
 			valueType = msgTwin.Metadata.Type
@@ -701,8 +703,8 @@ func dealTwinCompare(returnResult *dttype.DealTwinResult, deviceID string, key s
 			}
 		} else {
 			if strings.Compare(twin.Metadata.Type, "deleted") == 0 {
-				twin.Metadata = &dttype.TypeMetadata{Type: "string"}
-				cols["attr_type"] = "string"
+				twin.Metadata = &dttype.TypeMetadata{Type: stringType}
+				cols["attr_type"] = stringType
 				syncResult[key].Metadata = twin.Metadata
 				isChange = true
 			}
@@ -784,7 +786,7 @@ func dealTwinAdd(returnResult *dttype.DealTwinResult, deviceID string, key strin
 			return nil
 		}
 		// value type default string
-		valueType := "string"
+		valueType := stringType
 		if msgTwin.Metadata != nil {
 			valueType = msgTwin.Metadata.Type
 		}
@@ -824,7 +826,7 @@ func dealTwinAdd(returnResult *dttype.DealTwinResult, deviceID string, key strin
 			}
 			return nil
 		}
-		valueType := "string"
+		valueType := stringType
 		if msgTwin.Metadata != nil {
 			valueType = msgTwin.Metadata.Type
 		}
@@ -868,7 +870,7 @@ func dealTwinAdd(returnResult *dttype.DealTwinResult, deviceID string, key strin
 		msgTwin.Metadata.Type = deviceTwin.AttrType
 		isChange = true
 	} else {
-		deviceTwin.AttrType = "string"
+		deviceTwin.AttrType = stringType
 		isChange = true
 	}
 
diff --git a/edge/pkg/devicetwin/dtmanager/twin_test.go b/edge/pkg/devicetwin/dtmanager/twin_test.go
index fae293cd9..120f6f643 100644
--- a/edge/pkg/devicetwin/dtmanager/twin_test.go
+++ b/edge/pkg/devicetwin/dtmanager/twin_test.go
@@ -47,6 +47,8 @@ var (
 	typeDeleted = "deleted"
 	typeInt     = "int"
 	typeString  = "string"
+
+	valueType = "value"
 )
 
 // sendMsg sends message to receiverChannel and heartbeatChannel
@@ -74,7 +76,7 @@ func receiveMsg(commChannel chan interface{}, message *dttype.DTMessage) {
 // twinValueFunc returns a new TwinValue
 func twinValueFunc() *dttype.TwinValue {
 	var twinValue dttype.TwinValue
-	value := "value"
+	value := valueType
 	valueMetaData := &dttype.ValueMetadata{Timestamp: time.Now().UnixNano() / 1e6}
 	twinValue.Value = &value
 	twinValue.Metadata = valueMetaData
@@ -522,7 +524,7 @@ func TestDealDeviceTwinResult(t *testing.T) {
 
 	str := typeString
 	optionTrue := true
-	value := "value"
+	value := valueType
 	msgTwinValue := make(map[string]*dttype.MsgTwin)
 	msgTwinValue[deviceB] = &dttype.MsgTwin{
 		Expected: &dttype.TwinValue{Value: &value},
@@ -1326,7 +1328,7 @@ func TestDealTwinAdd(t *testing.T) {
 
 // TestDealMsgTwin is function to test DealMsgTwin
 func TestDealMsgTwin(t *testing.T) {
-	value := "value"
+	value := valueType
 	str := typeString
 	optionTrue := true
 	optionFalse := false
diff --git a/edge/pkg/edged/edged_pods.go b/edge/pkg/edged/edged_pods.go
index 073f0d1d9..09c984600 100644
--- a/edge/pkg/edged/edged_pods.go
+++ b/edge/pkg/edged/edged_pods.go
@@ -74,6 +74,8 @@ import (
 const (
 	etcHostsPath  = "/etc/hosts"
 	systemdSuffix = ".slice"
+
+	windows = "windows"
 )
 
 // GetActivePods returns non-terminal pods
@@ -287,7 +289,7 @@ func makeMounts(pod *v1.Pod, podDir string, container *v1.Container, hostName, h
 	// - OS is not Windows
 	// Kubernetes will not mount /etc/hosts if:
 	// - when the Pod sandbox is being created, its IP is still unknown. Hence, PodIP will not have been set.
-	mountEtcHostsFile := len(podIP) > 0 && runtime.GOOS != "windows"
+	mountEtcHostsFile := len(podIP) > 0 && runtime.GOOS != windows
 	klog.Infof("container: %v/%v/%v podIP: %q creating hosts mount: %v", pod.Namespace, pod.Name, container.Name, podIP, mountEtcHostsFile)
 	mounts := []kubecontainer.Mount{}
 	for _, mount := range container.VolumeMounts {
@@ -351,7 +353,7 @@ func makeMounts(pod *v1.Pod, podDir string, container *v1.Container, hostName, h
 
 		// Docker Volume Mounts fail on Windows if it is not of the form C:/
 		containerPath := mount.MountPath
-		if runtime.GOOS == "windows" {
+		if runtime.GOOS == windows {
 			if (strings.HasPrefix(hostPath, "/") || strings.HasPrefix(hostPath, "\\")) && !strings.Contains(hostPath, ":") {
 				hostPath = "c:" + hostPath
 			}
@@ -393,7 +395,7 @@ func makeMounts(pod *v1.Pod, podDir string, container *v1.Container, hostName, h
 }
 
 func makeAbsolutePath(goos, path string) string {
-	if goos != "windows" {
+	if goos != windows {
 		return "/" + path
 	}
 	// These are all for windows
@@ -601,7 +603,7 @@ func (e *edged) GenerateRunContainerOptions(pod *v1.Pod, container *v1.Container
 
 	// Disabling adding TerminationMessagePath on Windows as these files would be mounted as docker volume and
 	// Docker for Windows has a bug where only directories can be mounted
-	if len(container.TerminationMessagePath) != 0 && runtime.GOOS != "windows" {
+	if len(container.TerminationMessagePath) != 0 && runtime.GOOS != windows {
 		p := e.getPodContainerDir(pod.UID, container.Name)
 		if err := os.MkdirAll(p, 0750); err != nil {
 			klog.Errorf("Error on creating %q: %v", p, err)
diff --git a/edge/pkg/eventbus/mqtt/client.go b/edge/pkg/eventbus/mqtt/client.go
index c16c49f85..8b780ecf2 100644
--- a/edge/pkg/eventbus/mqtt/client.go
+++ b/edge/pkg/eventbus/mqtt/client.go
@@ -16,6 +16,8 @@ import (
 	"github.com/kubeedge/kubeedge/edge/pkg/eventbus/common/util"
 )
 
+const UploadTopic = "SYS/dis/upload_records"
+
 var (
 	// MQTTHub client
 	MQTTHub *Client
@@ -47,7 +49,7 @@ var (
 		"$hw/events/device/+/state/update",
 		"$hw/events/device/+/twin/+",
 		"$hw/events/node/+/membership/get",
-		"SYS/dis/upload_records",
+		UploadTopic,
 	}
 )
 
@@ -92,15 +94,15 @@ func OnSubMessageReceived(client MQTT.Client, message MQTT.Message) {
 	klog.Infof("OnSubMessageReceived receive msg from topic: %s", message.Topic())
 	// for "$hw/events/device/+/twin/+", "$hw/events/node/+/membership/get", send to twin
 	// for other, send to hub
-	// for "SYS/dis/upload_records", no need to base64 topic
+	// for topic, no need to base64 topic
 	var target string
 	resource := base64.URLEncoding.EncodeToString([]byte(message.Topic()))
 	if strings.HasPrefix(message.Topic(), "$hw/events/device") || strings.HasPrefix(message.Topic(), "$hw/events/node") {
 		target = modules.TwinGroup
 	} else {
 		target = modules.HubGroup
-		if message.Topic() == "SYS/dis/upload_records" {
-			resource = "SYS/dis/upload_records"
+		if message.Topic() == UploadTopic {
+			resource = UploadTopic
 		}
 	}
 	// routing key will be $hw.<project_id>.events.user.bus.response.cluster.<cluster_id>.node.<node_id>.<base64_topic>
diff --git a/edge/test/test.go b/edge/test/test.go
index 9ade18702..b506d5ab7 100644
--- a/edge/test/test.go
+++ b/edge/test/test.go
@@ -108,11 +108,11 @@ func (tm *testManager) podHandler(w http.ResponseWriter, req *http.Request) {
 		}
 
 		switch req.Method {
-		case "POST":
+		case http.MethodPost:
 			operation = model.InsertOperation
-		case "DELETE":
+		case http.MethodDelete:
 			operation = model.DeleteOperation
-		case "PUT":
+		case http.MethodPut:
 			operation = model.UpdateOperation
 		}
 
@@ -144,11 +144,11 @@ func (tm *testManager) deviceHandler(w http.ResponseWriter, req *http.Request) {
 			w.Write([]byte("unmarshal request body error"))
 		}
 		switch req.Method {
-		case "POST":
+		case http.MethodPost:
 			operation = model.InsertOperation
-		case "DELETE":
+		case http.MethodDelete:
 			operation = model.DeleteOperation
-		case "PUT":
+		case http.MethodPut:
 			operation = model.UpdateOperation
 		}
 		msgReq := message.BuildMsg("edgehub", "", "edgemgr", "membership", operation, Content)
@@ -173,11 +173,11 @@ func (tm *testManager) secretHandler(w http.ResponseWriter, req *http.Request) {
 		}
 
 		switch req.Method {
-		case "POST":
+		case http.MethodPost:
 			operation = model.InsertOperation
-		case "DELETE":
+		case http.MethodDelete:
 			operation = model.DeleteOperation
-		case "PUT":
+		case http.MethodPut:
 			operation = model.UpdateOperation
 		}
 
@@ -203,11 +203,11 @@ func (tm *testManager) configmapHandler(w http.ResponseWriter, req *http.Request
 		}
 
 		switch req.Method {
-		case "POST":
+		case http.MethodPost:
 			operation = model.InsertOperation
-		case "DELETE":
+		case http.MethodDelete:
 			operation = model.DeleteOperation
-		case "PUT":
+		case http.MethodPut:
 			operation = model.UpdateOperation
 		}
 
diff --git a/tests/e2e/deployment/device_crd_test.go b/tests/e2e/deployment/device_crd_test.go
index 0e1e750e4..664f5a5e5 100644
--- a/tests/e2e/deployment/device_crd_test.go
+++ b/tests/e2e/deployment/device_crd_test.go
@@ -33,6 +33,8 @@ const (
 	DeviceInstanceHandler = "/apis/devices.kubeedge.io/v1alpha1/namespaces/default/devices"
 	DeviceModelHandler    = "/apis/devices.kubeedge.io/v1alpha1/namespaces/default/devicemodels"
 	ConfigmapHandler      = "/api/v1/namespaces/default/configmaps"
+
+	off = "OFF"
 )
 
 var CRDTestTimerGroup *utils.TestTimerGroup = utils.NewTestTimerGroup()
@@ -302,7 +304,7 @@ var _ = Describe("Device Management test in E2E scenario", func() {
 			Eventually(func() bool {
 				return utils.TwinResult.Twin != nil
 			}, "20s", "2s").Should(Equal(true), "Device information not reaching edge!!")
-			stringValue := "OFF"
+			stringValue := off
 			expectedTwin := map[string]*utils.MsgTwin{
 				"temperature-enable": {
 					Expected: &utils.TwinValue{
@@ -355,7 +357,7 @@ var _ = Describe("Device Management test in E2E scenario", func() {
 			Eventually(func() bool {
 				return utils.TwinResult.Twin != nil
 			}, "20s", "2s").Should(Equal(true), "Device information not reaching edge!!")
-			stringValue := "OFF"
+			stringValue := off
 			expectedTwin := map[string]*utils.MsgTwin{
 				"power-status": {
 					Expected: &utils.TwinValue{
@@ -547,7 +549,7 @@ var _ = Describe("Device Management test in E2E scenario", func() {
 			newLedDevice := utils.NewLedDeviceInstance(nodeName)
 			time.Sleep(3 * time.Second)
 			var deviceTwinUpdateMessage utils.DeviceTwinUpdate
-			reportedValue := "OFF"
+			reportedValue := off
 			deviceTwinUpdateMessage.Twin = map[string]*utils.MsgTwin{
 				"power-status": {Actual: &utils.TwinValue{Value: &reportedValue}, Metadata: &utils.TypeMetadata{Type: "string"}},
 			}
@@ -558,7 +560,7 @@ var _ = Describe("Device Management test in E2E scenario", func() {
 			list, err := utils.GetDevice(&deviceList, ctx.Cfg.K8SMasterForKubeEdge+DeviceInstanceHandler, &newLedDevice)
 			Expect(err).To(BeNil())
 			Expect(list[0].Status.Twins[0].PropertyName).To(Equal("power-status"))
-			Expect(list[0].Status.Twins[0].Reported.Value).To(Equal("OFF"))
+			Expect(list[0].Status.Twins[0].Reported.Value).To(Equal(off))
 		})
 	})
 })
diff --git a/tests/e2e/mapper/bluetooth/bluetooth_test.go b/tests/e2e/mapper/bluetooth/bluetooth_test.go
index e9241f9d8..cf4e8be0f 100644
--- a/tests/e2e/mapper/bluetooth/bluetooth_test.go
+++ b/tests/e2e/mapper/bluetooth/bluetooth_test.go
@@ -37,6 +37,8 @@ import (
 	"github.com/kubeedge/kubeedge/tests/e2e/utils"
 )
 
+const topic = "$ke/device/bluetooth-mapper/mock-temp-sensor-instance/scheduler/result"
+
 var TokenClient Token
 var ClientOpts *MQTT.ClientOptions
 var Client MQTT.Client
@@ -55,7 +57,6 @@ var readWrittenData bool
 
 // DataConversion checks whether data is properly as expected by the data converter.
 func DataConversion(client MQTT.Client, message MQTT.Message) {
-	topic := "$ke/device/bluetooth-mapper/mock-temp-sensor-instance/scheduler/result"
 	expectedTemp := "32.375000"
 	dataConverted = false
 	if message.Topic() == topic {
@@ -73,7 +74,6 @@ func DataConversion(client MQTT.Client, message MQTT.Message) {
 
 // WriteDataReceived checks whether data is properly written to connected device.
 func WriteDataReceived(client MQTT.Client, message MQTT.Message) {
-	topic := "$ke/device/bluetooth-mapper/mock-temp-sensor-instance/scheduler/result"
 	readWrittenData = false
 	if message.Topic() == topic {
 		devicePayload := message.Payload()
@@ -91,7 +91,6 @@ func WriteDataReceived(client MQTT.Client, message MQTT.Message) {
 
 // ScheculeExecute counts the number of times schedule is executed by the Scheduler.
 func ScheduleExecute(client MQTT.Client, message MQTT.Message) {
-	topic := "$ke/device/bluetooth-mapper/mock-temp-sensor-instance/scheduler/result"
 	expectedTemp := "36"
 	if message.Topic() == topic {
 		devicePayload := message.Payload()
@@ -119,10 +118,9 @@ var _ = Describe("Application deployment test in E2E scenario", func() {
 				utils.Infof("Connection successful")
 			}
 			Expect(TokenClient.Error()).NotTo(HaveOccurred())
-			scheduletopic := "$ke/device/bluetooth-mapper/mock-temp-sensor-instance/scheduler/result"
-			Token := Client.Subscribe(scheduletopic, 0, WriteDataReceived)
+			Token := Client.Subscribe(topic, 0, WriteDataReceived)
 			if Token.Wait() && TokenClient.Error() != nil {
-				utils.Fatalf("Subscribe to Topic  Failed  %s, %s", TokenClient.Error(), scheduletopic)
+				utils.Fatalf("Subscribe to Topic  Failed  %s, %s", TokenClient.Error(), topic)
 			}
 			Expect(TokenClient.Error()).NotTo(HaveOccurred())
 		})
@@ -164,10 +162,9 @@ var _ = Describe("Application deployment test in E2E scenario", func() {
 				utils.Infof("Subscribe Connection Successful")
 			}
 			Expect(TokenClient.Error()).NotTo(HaveOccurred())
-			scheduletopic := "$ke/device/bluetooth-mapper/mock-temp-sensor-instance/scheduler/result"
-			Token := Client.Subscribe(scheduletopic, 0, DataConversion)
+			Token := Client.Subscribe(topic, 0, DataConversion)
 			if Token.Wait() && TokenClient.Error() != nil {
-				utils.Fatalf("Subscribe to Topic  Failed  %s, %s", TokenClient.Error(), scheduletopic)
+				utils.Fatalf("Subscribe to Topic  Failed  %s, %s", TokenClient.Error(), topic)
 			}
 			Expect(TokenClient.Error()).NotTo(HaveOccurred())
 			var expectedSchedule []scheduler.Schedule
diff --git a/tests/e2e/utils/common.go b/tests/e2e/utils/common.go
index a1308bbb6..897f28888 100644
--- a/tests/e2e/utils/common.go
+++ b/tests/e2e/utils/common.go
@@ -48,6 +48,11 @@ const (
 	TwinETUpdateSuffix    = "/twin/update"
 	TwinETGetSuffix       = "/twin/get"
 	TwinETGetResultSuffix = "/twin/get/result"
+
+	BlueTooth         = "bluetooth"
+	ModBus            = "modbus"
+	Led               = "led"
+	IncorrectInstance = "incorrect-instance"
 )
 
 var (
@@ -325,14 +330,14 @@ func HandlePod(operation string, apiserver string, UID string, pod *v1.Pod) bool
 		Transport: tr,
 	}
 	switch operation {
-	case "POST":
+	case http.MethodPost:
 		body := pod
 		respBytes, err := json.Marshal(body)
 		if err != nil {
 			Fatalf("Marshalling body failed: %v", err)
 		}
 		req, err = http.NewRequest(http.MethodPost, apiserver, bytes.NewBuffer(respBytes))
-	case "DELETE":
+	case http.MethodDelete:
 		req, err = http.NewRequest(http.MethodDelete, apiserver+UID, body)
 	}
 	if err != nil {
@@ -367,7 +372,7 @@ func HandleDeployment(IsCloudCore, IsEdgeCore bool, operation, apiserver, UID, I
 	}
 
 	switch operation {
-	case "POST":
+	case http.MethodPost:
 		depObj := newDeployment(IsCloudCore, IsEdgeCore, UID, ImageURL, nodeselector, configmapname, replica)
 		if err != nil {
 			Fatalf("GenerateDeploymentBody marshalling failed: %v", err)
@@ -377,7 +382,7 @@ func HandleDeployment(IsCloudCore, IsEdgeCore bool, operation, apiserver, UID, I
 			Fatalf("Marshalling body failed: %v", err)
 		}
 		req, err = http.NewRequest(http.MethodPost, apiserver, bytes.NewBuffer(respBytes))
-	case "DELETE":
+	case http.MethodDelete:
 		req, err = http.NewRequest(http.MethodDelete, apiserver+UID, body)
 	}
 	if err != nil {
@@ -543,7 +548,7 @@ func HandleDeviceModel(operation string, apiserver string, UID string, protocolT
 	}
 
 	switch operation {
-	case "POST":
+	case http.MethodPost:
 		body := newDeviceModelObject(protocolType, false)
 		respBytes, err := json.Marshal(body)
 		if err != nil {
@@ -559,7 +564,7 @@ func HandleDeviceModel(operation string, apiserver string, UID string, protocolT
 		}
 		req, err = http.NewRequest(http.MethodPatch, apiserver+UID, bytes.NewBuffer(respBytes))
 		req.Header.Set("Content-Type", "application/merge-patch+json")
-	case "DELETE":
+	case http.MethodDelete:
 		req, err = http.NewRequest(http.MethodDelete, apiserver+UID, body)
 		req.Header.Set("Content-Type", "application/json")
 	}
@@ -592,7 +597,7 @@ func HandleDeviceInstance(operation string, apiserver string, nodeSelector strin
 		Transport: tr,
 	}
 	switch operation {
-	case "POST":
+	case http.MethodPost:
 		body := newDeviceInstanceObject(nodeSelector, protocolType, false)
 		respBytes, err := json.Marshal(body)
 		if err != nil {
@@ -608,7 +613,7 @@ func HandleDeviceInstance(operation string, apiserver string, nodeSelector strin
 		}
 		req, err = http.NewRequest(http.MethodPatch, apiserver+UID, bytes.NewBuffer(respBytes))
 		req.Header.Set("Content-Type", "application/merge-patch+json")
-	case "DELETE":
+	case http.MethodDelete:
 		req, err = http.NewRequest(http.MethodDelete, apiserver+UID, body)
 		req.Header.Set("Content-Type", "application/json")
 	}
@@ -633,24 +638,24 @@ func newDeviceInstanceObject(nodeSelector string, protocolType string, updated b
 	var deviceInstance v1alpha1.Device
 	if !updated {
 		switch protocolType {
-		case "bluetooth":
+		case BlueTooth:
 			deviceInstance = NewBluetoothDeviceInstance(nodeSelector)
-		case "modbus":
+		case ModBus:
 			deviceInstance = NewModbusDeviceInstance(nodeSelector)
-		case "led":
+		case Led:
 			deviceInstance = NewLedDeviceInstance(nodeSelector)
-		case "incorrect-instance":
+		case IncorrectInstance:
 			deviceInstance = IncorrectDeviceInstance()
 		}
 	} else {
 		switch protocolType {
-		case "bluetooth":
+		case BlueTooth:
 			deviceInstance = UpdatedBluetoothDeviceInstance(nodeSelector)
-		case "modbus":
+		case ModBus:
 			deviceInstance = UpdatedModbusDeviceInstance(nodeSelector)
-		case "led":
+		case Led:
 			deviceInstance = UpdatedLedDeviceInstance(nodeSelector)
-		case "incorrect-instance":
+		case IncorrectInstance:
 			deviceInstance = IncorrectDeviceInstance()
 		}
 	}
@@ -662,22 +667,22 @@ func newDeviceModelObject(protocolType string, updated bool) *v1alpha1.DeviceMod
 	var deviceModel v1alpha1.DeviceModel
 	if !updated {
 		switch protocolType {
-		case "bluetooth":
+		case BlueTooth:
 			deviceModel = NewBluetoothDeviceModel()
-		case "modbus":
+		case ModBus:
 			deviceModel = NewModbusDeviceModel()
-		case "led":
+		case Led:
 			deviceModel = NewLedDeviceModel()
 		case "incorrect-model":
 			deviceModel = IncorrectDeviceModel()
 		}
 	} else {
 		switch protocolType {
-		case "bluetooth":
+		case BlueTooth:
 			deviceModel = UpdatedBluetoothDeviceModel()
-		case "modbus":
+		case ModBus:
 			deviceModel = UpdatedModbusDeviceModel()
-		case "led":
+		case Led:
 			deviceModel = UpdatedLedDeviceModel()
 		case "incorrect-model":
 			deviceModel = IncorrectDeviceModel()