downstream.go

/*
Copyright 2019 The KubeEdge 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 controller

import (
	"encoding/json"
	"reflect"
	"strconv"
	"time"

	"github.com/kubeedge/beehive/pkg/common/log"
	"github.com/kubeedge/beehive/pkg/core/model"
	"github.com/kubeedge/kubeedge/cloud/pkg/devicecontroller/apis/devices/v1alpha1"
	"github.com/kubeedge/kubeedge/cloud/pkg/devicecontroller/constants"
	"github.com/kubeedge/kubeedge/cloud/pkg/devicecontroller/manager"
	"github.com/kubeedge/kubeedge/cloud/pkg/devicecontroller/messagelayer"
	"github.com/kubeedge/kubeedge/cloud/pkg/devicecontroller/types"
	"github.com/kubeedge/kubeedge/cloud/pkg/devicecontroller/utils"

	"github.com/satori/go.uuid"
	"k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/watch"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/rest"
)

// Constants for protocol, datatype, configmap, deviceProfile
const (
	OPCUA     = "opcua"
	ModbusRTU = "modbus-rtu"
	ModbusTCP = "modbus-tcp"
	Modbus    = "modbus"
	Bluetooth = "bluetooth"

	DataTypeInt    = "int"
	DataTypeString = "string"

	ConfigMapKind    = "ConfigMap"
	ConfigMapVersion = "v1"

	DeviceProfileConfigPrefix = "device-profile-config-"

	DeviceProfileJSON = "deviceProfile.json"
)

// CacheDevice is the struct save device data for check device is really changed
type CacheDevice struct {
	metav1.ObjectMeta
	Spec   v1alpha1.DeviceSpec
	Status v1alpha1.DeviceStatus
}

// CacheDeviceModel is the struct save DeviceModel data for check DeviceModel is really changed
type CacheDeviceModel struct {
	metav1.ObjectMeta
	Spec v1alpha1.DeviceModelSpec
}

// DownstreamController watch kubernetes api server and send change to edge
type DownstreamController struct {
	kubeClient   *kubernetes.Clientset
	messageLayer messagelayer.MessageLayer

	deviceManager *manager.DeviceManager
	deviceStop    chan struct{}

	deviceModelManager *manager.DeviceModelManager
	deviceModelStop    chan struct{}

	configMapManager *manager.ConfigMapManager

	crdClient *rest.RESTClient
}

// syncDeviceModel is used to get events from informer
func (dc *DownstreamController) syncDeviceModel(stop chan struct{}) {
	running := true
	for running {
		select {
		case e := <-dc.deviceModelManager.Events():
			deviceModel, ok := e.Object.(*v1alpha1.DeviceModel)
			if !ok {
				log.LOGGER.Warnf("object type: %T unsupported", deviceModel)
				continue
			}
			switch e.Type {
			case watch.Added:
				dc.deviceModelAdded(deviceModel)
			case watch.Deleted:
				dc.deviceModelDeleted(deviceModel)
			case watch.Modified:
				dc.deviceModelUpdated(deviceModel)
			default:
				log.LOGGER.Warnf("deviceModel event type: %s unsupported", e.Type)
			}
		case <-stop:
			log.LOGGER.Infof("stop syncDeviceModel")
			running = false
		}
	}
}

// deviceModelAdded is function to process addition of new deviceModel in apiserver
func (dc *DownstreamController) deviceModelAdded(deviceModel *v1alpha1.DeviceModel) {
	// nothing to do when deviceModel added, only add in map
	dc.deviceModelManager.DeviceModel.Store(deviceModel.Name, &CacheDeviceModel{ObjectMeta: deviceModel.ObjectMeta, Spec: deviceModel.Spec})
}

// isDeviceModelUpdated is function to check if deviceModel is actually updated
func isDeviceModelUpdated(oldTwin *CacheDeviceModel, newTwin *v1alpha1.DeviceModel) bool {
	// does not care fields
	oldTwin.ObjectMeta.ResourceVersion = newTwin.ObjectMeta.ResourceVersion
	oldTwin.ObjectMeta.Generation = newTwin.ObjectMeta.Generation

	// return true if ObjectMeta or Spec or Status changed, else false
	return !reflect.DeepEqual(oldTwin.ObjectMeta, newTwin.ObjectMeta) || !reflect.DeepEqual(oldTwin.Spec, newTwin.Spec)
}

// deviceModelUpdated is function to process updated deviceModel
func (dc *DownstreamController) deviceModelUpdated(deviceModel *v1alpha1.DeviceModel) {
	value, ok := dc.deviceModelManager.DeviceModel.Load(deviceModel.Name)
	dc.deviceModelManager.DeviceModel.Store(deviceModel.Name, &CacheDeviceModel{ObjectMeta: deviceModel.ObjectMeta, Spec: deviceModel.Spec})
	if ok {
		cachedDeviceModel := value.(*CacheDeviceModel)
		if isDeviceModelUpdated(cachedDeviceModel, deviceModel) {
			dc.updateAllConfigMaps(deviceModel)
		}
	} else {
		dc.deviceModelAdded(deviceModel)
	}
}

// updateAllConfigMaps is function to update configMaps which refer to an updated deviceModel
func (dc *DownstreamController) updateAllConfigMaps(deviceModel *v1alpha1.DeviceModel) {
	//TODO: add logic to update all config maps, How to manage if a property is deleted but a device is referring that property. Need to come up with a design.
}

// deviceModelDeleted is function to process deleted deviceModel
func (dc *DownstreamController) deviceModelDeleted(deviceModel *v1alpha1.DeviceModel) {
	// TODO: Need to use finalizer like method to delete all devices referring to this model. Need to come up with a design.
	dc.deviceModelManager.DeviceModel.Delete(deviceModel.Name)
}

// syncDevice is used to get device events from informer
func (dc *DownstreamController) syncDevice(stop chan struct{}) {
	running := true
	for running {
		select {
		case e := <-dc.deviceManager.Events():
			device, ok := e.Object.(*v1alpha1.Device)
			if !ok {
				log.LOGGER.Warnf("Object type: %T unsupported", device)
				continue
			}
			switch e.Type {
			case watch.Added:
				dc.deviceAdded(device)
			case watch.Deleted:
				dc.deviceDeleted(device)
			case watch.Modified:
				dc.deviceUpdated(device)
			default:
				log.LOGGER.Warnf("Device event type: %s unsupported", e.Type)
			}
		case <-stop:
			log.LOGGER.Infof("Stop syncDevice")
			running = false
		}
	}
}

// addToConfigMap adds device in the configmap
func (dc *DownstreamController) addToConfigMap(device *v1alpha1.Device) {
	configMap, ok := dc.configMapManager.ConfigMap.Load(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values[0])
	if !ok {
		nodeConfigMap := &v1.ConfigMap{}
		nodeConfigMap.Kind = ConfigMapKind
		nodeConfigMap.APIVersion = ConfigMapVersion
		nodeConfigMap.Name = DeviceProfileConfigPrefix + device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values[0]
		nodeConfigMap.Namespace = device.Namespace
		nodeConfigMap.Data = make(map[string]string)
		// TODO: how to handle 2 device of multiple namespaces bind to same node ?
		dc.addDeviceProfile(device, nodeConfigMap)
		// store new config map
		dc.configMapManager.ConfigMap.Store(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values[0], nodeConfigMap)

		if _, err := dc.kubeClient.CoreV1().ConfigMaps(device.Namespace).Get(nodeConfigMap.Name, metav1.GetOptions{}); err != nil {
			if _, err := dc.kubeClient.CoreV1().ConfigMaps(device.Namespace).Create(nodeConfigMap); err != nil {
				log.LOGGER.Errorf("Failed to create config map %v in namespace %v, error %v", nodeConfigMap, device.Namespace, err)
				return
			}
		}
		if _, err := dc.kubeClient.CoreV1().ConfigMaps(device.Namespace).Update(nodeConfigMap); err != nil {
			log.LOGGER.Errorf("Failed to update config map %v in namespace %v, error %v", nodeConfigMap, device.Namespace, err)
			return
		}
		return
	}
	nodeConfigMap, ok := configMap.(*v1.ConfigMap)
	if !ok {
		log.LOGGER.Errorf("Failed to assert to configmap")
		return
	}
	dc.addDeviceProfile(device, nodeConfigMap)
	// store new config map
	dc.configMapManager.ConfigMap.Store(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values[0], nodeConfigMap)
	if _, err := dc.kubeClient.CoreV1().ConfigMaps(device.Namespace).Update(nodeConfigMap); err != nil {
		log.LOGGER.Errorf("Failed to update config map %v in namespace %v", nodeConfigMap, device.Namespace)
		return
	}
}

// addDeviceProfile is function to add deviceProfile in configMap
func (dc *DownstreamController) addDeviceProfile(device *v1alpha1.Device, configMap *v1.ConfigMap) {
	deviceProfile := &types.DeviceProfile{}
	dp, ok := configMap.Data[DeviceProfileJSON]
	if !ok {
		// create deviceProfileStruct
		deviceProfile.DeviceInstances = make([]*types.DeviceInstance, 0)
		deviceProfile.DeviceModels = make([]*types.DeviceModel, 0)
		deviceProfile.PropertyVisitors = make([]*types.PropertyVisitor, 0)
		deviceProfile.Protocols = make([]*types.Protocol, 0)
	} else {
		err := json.Unmarshal([]byte(dp), deviceProfile)
		if err != nil {
			log.LOGGER.Errorf("Failed to Unmarshal deviceprofile: %v", deviceProfile)
			return
		}
	}

	addDeviceInstanceAndProtocol(device, deviceProfile)
	dm, ok := dc.deviceModelManager.DeviceModel.Load(device.Spec.DeviceModelRef.Name)
	if !ok {
		log.LOGGER.Errorf("Failed to get device model %v", device.Spec.DeviceModelRef.Name)
		return
	}
	deviceModel := dm.(*CacheDeviceModel)
	// if model already exists no need to add model and visitors
	checkModelExists := false
	for _, dm := range deviceProfile.DeviceModels {
		if dm.Name == deviceModel.Name {
			checkModelExists = true
			break
		}
	}
	if checkModelExists != true {
		addDeviceModelAndVisitors(deviceModel, deviceProfile)
	}
	bytes, err := json.Marshal(deviceProfile)
	if err != nil {
		log.LOGGER.Errorf("Failed to marshal deviceprofile: %v", deviceProfile)
		return
	}
	configMap.Data[DeviceProfileJSON] = string(bytes)
}

// addDeviceModelAndVisitors adds deviceModels and deviceVisitors in configMap
func addDeviceModelAndVisitors(deviceModel *CacheDeviceModel, deviceProfile *types.DeviceProfile) {
	model := &types.DeviceModel{}
	model.Name = deviceModel.Name
	model.Properties = make([]*types.Property, 0)
	for _, ppt := range deviceModel.Spec.Properties {
		property := &types.Property{}
		property.Name = ppt.Name
		property.Description = ppt.Description
		if ppt.Type.Int != nil {
			property.AccessMode = string(ppt.Type.Int.AccessMode)
			property.DataType = DataTypeInt
			property.DefaultValue = ppt.Type.Int.DefaultValue
			property.Maximum = ppt.Type.Int.Maximum
			property.Minimum = ppt.Type.Int.Minimum
			property.Unit = ppt.Type.Int.Unit
		} else if ppt.Type.String != nil {
			property.AccessMode = string(ppt.Type.String.AccessMode)
			property.DataType = DataTypeString
			property.DefaultValue = ppt.Type.String.DefaultValue
		}
		model.Properties = append(model.Properties, property)
	}
	deviceProfile.DeviceModels = append(deviceProfile.DeviceModels, model)
	for _, pptv := range deviceModel.Spec.PropertyVisitors {
		propertyVisitor := &types.PropertyVisitor{}
		propertyVisitor.Name = pptv.PropertyName
		propertyVisitor.PropertyName = pptv.PropertyName
		propertyVisitor.ModelName = deviceModel.Name
		if pptv.Modbus != nil {
			propertyVisitor.Protocol = Modbus
			propertyVisitor.VisitorConfig = pptv.Modbus
		} else if pptv.OpcUA != nil {
			propertyVisitor.Protocol = OPCUA
			propertyVisitor.VisitorConfig = pptv.OpcUA
		} else if pptv.Bluetooth != nil {
			propertyVisitor.Protocol = Bluetooth
			propertyVisitor.VisitorConfig = pptv.Bluetooth
		}
		deviceProfile.PropertyVisitors = append(deviceProfile.PropertyVisitors, propertyVisitor)
	}
}

// addDeviceInstanceAndProtocol adds deviceInstance and protocol in configMap
func addDeviceInstanceAndProtocol(device *v1alpha1.Device, deviceProfile *types.DeviceProfile) {
	deviceInstance := &types.DeviceInstance{}
	deviceProtocol := &types.Protocol{}
	deviceInstance.ID = device.Name
	deviceInstance.Name = device.Name
	deviceInstance.Model = device.Spec.DeviceModelRef.Name
	var protocol string
	if device.Spec.Protocol.OpcUA != nil {
		protocol = OPCUA + "-" + device.Name
		deviceInstance.Protocol = protocol
		deviceProtocol.Name = protocol
		deviceProtocol.Protocol = OPCUA
		deviceProtocol.ProtocolConfig = device.Spec.Protocol.OpcUA
	} else if device.Spec.Protocol.Modbus != nil && device.Spec.Protocol.Modbus.RTU != nil {
		protocol = ModbusRTU + "-" + device.Name
		deviceInstance.Protocol = protocol
		deviceProtocol.Name = protocol
		deviceProtocol.Protocol = ModbusRTU
		deviceProtocol.ProtocolConfig = device.Spec.Protocol.Modbus.RTU
	} else if device.Spec.Protocol.Modbus != nil && device.Spec.Protocol.Modbus.TCP != nil {
		protocol = ModbusTCP + "-" + device.Name
		deviceInstance.Protocol = protocol
		deviceProtocol.Name = protocol
		deviceProtocol.Protocol = ModbusTCP
		deviceProtocol.ProtocolConfig = device.Spec.Protocol.Modbus.TCP
	} else if device.Spec.Protocol.Bluetooth != nil {
		protocol = Bluetooth + "-" + device.Name
		deviceInstance.Protocol = protocol
		deviceProtocol.Name = protocol
		deviceProtocol.Protocol = Bluetooth
		deviceProtocol.ProtocolConfig = device.Spec.Protocol.Bluetooth
	} else {
		log.LOGGER.Warnf("Device doesnt support valid protocol")
	}
	deviceProfile.DeviceInstances = append(deviceProfile.DeviceInstances, deviceInstance)
	deviceProfile.Protocols = append(deviceProfile.Protocols, deviceProtocol)
}

// deviceAdded creates a device, adds in deviceManagers map, send a message to edge node if node selector is present.
func (dc *DownstreamController) deviceAdded(device *v1alpha1.Device) {
	dc.deviceManager.Device.Store(device.Name, &CacheDevice{ObjectMeta: device.ObjectMeta, Spec: device.Spec, Status: device.Status})
	if len(device.Spec.NodeSelector.NodeSelectorTerms) != 0 && len(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions) != 0 && len(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values) != 0 {
		dc.addToConfigMap(device)
		edgeDevice := createDevice(device)
		msg := model.NewMessage("")

		resource, err := messagelayer.BuildResource(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values[0], "membership", "")
		if err != nil {
			log.LOGGER.Warnf("Built message resource failed with error: %s", err)
			return
		}
		msg.BuildRouter(constants.DeviceControllerModuleName, constants.GroupTwin, resource, model.UpdateOperation)

		content := types.MembershipUpdate{AddDevices: []types.Device{
			edgeDevice,
		}}
		content.EventID = uuid.NewV4().String()
		content.Timestamp = time.Now().UnixNano() / 1e6
		msg.Content = content

		err = dc.messageLayer.Send(*msg)
		if err != nil {
			log.LOGGER.Errorf("Failed to send device addition message %v due to error %v", msg, err)
		}
	}
}

// createDevice creates a device from CRD
func createDevice(device *v1alpha1.Device) types.Device {
	edgeDevice := types.Device{
		// ID and name can be used as ID as we are using CRD and name(key in ETCD) will always be unique
		ID:   device.Name,
		Name: device.Name,
	}

	description, ok := device.Labels["description"]
	if ok {
		edgeDevice.Description = description
	}

	// TODO: optional is Always false, currently not present in CRD definition, need to add or remove from deviceTwin @ Edge
	opt := false
	optional := &opt
	twin := make(map[string]*types.MsgTwin)
	for i, dtwin := range device.Status.Twins {
		expected := &types.TwinValue{}
		expected.Value = &device.Status.Twins[i].Desired.Value
		metadataType, ok := device.Status.Twins[i].Desired.Metadata["type"]
		if !ok {
			metadataType = "string"
		}
		timestamp := time.Now().UnixNano() / 1e6

		metadata := &types.ValueMetadata{Timestamp: timestamp}
		expected.Metadata = metadata

		// TODO: how to manage versioning ??
		cloudVersion, err := strconv.ParseInt(device.ResourceVersion, 10, 64)
		if err != nil {
			log.LOGGER.Warnf("Failed to parse cloud version due to error %v", err)
		}
		twinVersion := &types.TwinVersion{CloudVersion: cloudVersion, EdgeVersion: 0}
		msgTwin := &types.MsgTwin{
			Expected:        expected,
			Optional:        optional,
			Metadata:        &types.TypeMetadata{Type: metadataType},
			ExpectedVersion: twinVersion,
		}
		twin[dtwin.PropertyName] = msgTwin
	}
	edgeDevice.Twin = twin
	return edgeDevice
}

// isDeviceUpdated checks if device is actually updated
func isDeviceUpdated(oldTwin *CacheDevice, newTwin *v1alpha1.Device) bool {
	// does not care fields
	oldTwin.ObjectMeta.ResourceVersion = newTwin.ObjectMeta.ResourceVersion
	oldTwin.ObjectMeta.Generation = newTwin.ObjectMeta.Generation

	// return true if ObjectMeta or Spec or Status changed, else false
	return !reflect.DeepEqual(oldTwin.ObjectMeta, newTwin.ObjectMeta) || !reflect.DeepEqual(oldTwin.Spec, newTwin.Spec) || !reflect.DeepEqual(oldTwin.Status, newTwin.Status)
}

// isNodeSelectorUpdated checks if nodeSelector is updated
func isNodeSelectorUpdated(oldTwin *v1.NodeSelector, newTwin *v1.NodeSelector) bool {
	return !reflect.DeepEqual(oldTwin.NodeSelectorTerms, newTwin.NodeSelectorTerms)
}

// isProtocolConfigUpdated checks if protocol is updated
func isProtocolConfigUpdated(oldTwin *v1alpha1.ProtocolConfig, newTwin *v1alpha1.ProtocolConfig) bool {
	return !reflect.DeepEqual(oldTwin, newTwin)
}

// updateProtocolInConfigMap updates the protocol in the deviceProfile in configmap
func (dc *DownstreamController) updateProtocolInConfigMap(device *v1alpha1.Device) {
	if len(device.Spec.NodeSelector.NodeSelectorTerms) != 0 && len(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions) != 0 && len(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values) != 0 {
		configMap, ok := dc.configMapManager.ConfigMap.Load(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values[0])
		if ok {
			nodeConfigMap, ok := configMap.(*v1.ConfigMap)
			if !ok {
				log.LOGGER.Errorf("Failed to assert to configmap")
				return
			}
			dp, ok := nodeConfigMap.Data[DeviceProfileJSON]
			if !ok || dp == "{}" {
				// This case should never be hit as we delete empty configmaps
				log.LOGGER.Errorf("Failed to get deviceProfile from configmap data or deviceProfile is empty")
				return
			}

			deviceProfile := &types.DeviceProfile{}
			if err := json.Unmarshal([]byte(dp), deviceProfile); err != nil {
				log.LOGGER.Errorf("Failed to unmarshal due to error: %v", err)
				return
			}
			var oldProtocol string
			for _, devInst := range deviceProfile.DeviceInstances {
				if device.Name == devInst.Name {
					oldProtocol = devInst.Protocol
					break
				}
			}

			// delete the old protocol
			for i, ptcl := range deviceProfile.Protocols {
				if ptcl.Name == oldProtocol {
					deviceProfile.Protocols = append(deviceProfile.Protocols[:i], deviceProfile.Protocols[i+1:]...)
					break
				}
			}

			// add new protocol
			deviceProtocol := &types.Protocol{}
			var protocol string
			if device.Spec.Protocol.OpcUA != nil {
				protocol = OPCUA + "-" + device.Name
				deviceProtocol.Name = protocol
				deviceProtocol.Protocol = OPCUA
				deviceProtocol.ProtocolConfig = device.Spec.Protocol.OpcUA
			} else if device.Spec.Protocol.Modbus != nil && device.Spec.Protocol.Modbus.RTU != nil {
				protocol = ModbusRTU + "-" + device.Name
				deviceProtocol.Name = protocol
				deviceProtocol.Protocol = ModbusRTU
				deviceProtocol.ProtocolConfig = device.Spec.Protocol.Modbus.RTU
			} else if device.Spec.Protocol.Modbus != nil && device.Spec.Protocol.Modbus.TCP != nil {
				protocol = ModbusTCP + "-" + device.Name
				deviceProtocol.Name = protocol
				deviceProtocol.Protocol = ModbusTCP
				deviceProtocol.ProtocolConfig = device.Spec.Protocol.Modbus.TCP
			} else if device.Spec.Protocol.Bluetooth != nil {
				protocol = Bluetooth + "-" + device.Name
				deviceProtocol.Name = protocol
				deviceProtocol.Protocol = Bluetooth
				deviceProtocol.ProtocolConfig = device.Spec.Protocol.Bluetooth
			} else {
				log.LOGGER.Warnf("Unsupported device protocol")
			}

			// update the protocol in deviceInstance
			for _, devInst := range deviceProfile.DeviceInstances {
				if device.Name == devInst.Name {
					devInst.Protocol = protocol
					break
				}
			}
			deviceProfile.Protocols = append(deviceProfile.Protocols, deviceProtocol)

			bytes, err := json.Marshal(deviceProfile)
			if err != nil {
				log.LOGGER.Errorf("Failed to marshal deviceprofile: %v", deviceProfile)
				return
			}
			nodeConfigMap.Data[DeviceProfileJSON] = string(bytes)
			// store new config map
			dc.configMapManager.ConfigMap.Store(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values[0], nodeConfigMap)
			if _, err := dc.kubeClient.CoreV1().ConfigMaps(device.Namespace).Update(nodeConfigMap); err != nil {
				log.LOGGER.Errorf("Failed to update config map %v in namespace %v", nodeConfigMap, device.Namespace)
				return
			}
		}
	}
}

// deviceUpdated updates the map, check if device is actually updated.
// If nodeSelector is updated, call add device for newNode, deleteDevice for old Node.
// If twin is updated, send twin update message to edge
func (dc *DownstreamController) deviceUpdated(device *v1alpha1.Device) {
	value, ok := dc.deviceManager.Device.Load(device.Name)
	dc.deviceManager.Device.Store(device.Name, &CacheDevice{ObjectMeta: device.ObjectMeta, Spec: device.Spec, Status: device.Status})
	if ok {
		cachedDevice := value.(*CacheDevice)
		if isDeviceUpdated(cachedDevice, device) {
			// if node selector updated delete from old node and create in new node
			if isNodeSelectorUpdated(cachedDevice.Spec.NodeSelector, device.Spec.NodeSelector) {
				dc.deviceAdded(device)
				deletedDevice := &v1alpha1.Device{ObjectMeta: cachedDevice.ObjectMeta,
					Spec:     cachedDevice.Spec,
					Status:   cachedDevice.Status,
					TypeMeta: device.TypeMeta,
				}
				dc.deviceDeleted(deletedDevice)

			} else if isProtocolConfigUpdated(&cachedDevice.Spec.Protocol, &device.Spec.Protocol) {
				dc.updateProtocolInConfigMap(device)
			} else {
				// TODO: add an else if condition to check if DeviceModelReference has changed, if yes whether deviceModelReference exists
				twin := make(map[string]*types.MsgTwin)
				addUpdatedTwins(device.Status.Twins, twin, device.ResourceVersion)
				addDeletedTwins(cachedDevice.Status.Twins, device.Status.Twins, twin, device.ResourceVersion)
				msg := model.NewMessage("")

				resource, err := messagelayer.BuildResource(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values[0], "device/"+device.Name+"/twin/cloud_updated", "")
				if err != nil {
					log.LOGGER.Warnf("Built message resource failed with error: %s", err)
					return
				}
				msg.BuildRouter(constants.DeviceControllerModuleName, constants.GroupTwin, resource, model.UpdateOperation)
				content := types.DeviceTwinUpdate{Twin: twin}
				content.EventID = uuid.NewV4().String()
				content.Timestamp = time.Now().UnixNano() / 1e6
				msg.Content = content

				err = dc.messageLayer.Send(*msg)
				if err != nil {
					log.LOGGER.Errorf("Failed to send deviceTwin message %v due to error %v", msg, err)
				}
			}
		}
	} else {
		// If device not present in device map means it is not modified and added.
		dc.deviceAdded(device)
	}
}

// addDeletedTwins add deleted twins in the message
func addDeletedTwins(oldTwin []v1alpha1.Twin, newTwin []v1alpha1.Twin, twin map[string]*types.MsgTwin, version string) {
	opt := false
	optional := &opt
	for i, dtwin := range oldTwin {
		if !ifTwinPresent(dtwin, newTwin) {
			expected := &types.TwinValue{}
			expected.Value = &oldTwin[i].Desired.Value
			timestamp := time.Now().UnixNano() / 1e6

			metadata := &types.ValueMetadata{Timestamp: timestamp}
			expected.Metadata = metadata

			// TODO: how to manage versioning ??
			cloudVersion, err := strconv.ParseInt(version, 10, 64)
			if err != nil {
				log.LOGGER.Warnf("Failed to parse cloud version due to error %v", err)
			}
			twinVersion := &types.TwinVersion{CloudVersion: cloudVersion, EdgeVersion: 0}
			msgTwin := &types.MsgTwin{
				Expected:        expected,
				Optional:        optional,
				Metadata:        &types.TypeMetadata{Type: "deleted"},
				ExpectedVersion: twinVersion,
			}
			twin[dtwin.PropertyName] = msgTwin
		}
	}
}

// ifTwinPresent checks if twin is present in the array of twins
func ifTwinPresent(twin v1alpha1.Twin, newTwins []v1alpha1.Twin) bool {
	for _, dtwin := range newTwins {
		if twin.PropertyName == dtwin.PropertyName {
			return true
		}
	}
	return false
}

// addUpdatedTwins is function of add updated twins to send to edge
func addUpdatedTwins(newTwin []v1alpha1.Twin, twin map[string]*types.MsgTwin, version string) {
	opt := false
	optional := &opt
	for i, dtwin := range newTwin {
		expected := &types.TwinValue{}
		expected.Value = &newTwin[i].Desired.Value
		metadataType, ok := newTwin[i].Desired.Metadata["type"]
		if !ok {
			metadataType = "string"
		}
		timestamp := time.Now().UnixNano() / 1e6

		metadata := &types.ValueMetadata{Timestamp: timestamp}
		expected.Metadata = metadata

		// TODO: how to manage versioning ??
		cloudVersion, err := strconv.ParseInt(version, 10, 64)
		if err != nil {
			log.LOGGER.Warnf("Failed to parse cloud version due to error %v", err)
		}
		twinVersion := &types.TwinVersion{CloudVersion: cloudVersion, EdgeVersion: 0}
		msgTwin := &types.MsgTwin{
			Expected:        expected,
			Optional:        optional,
			Metadata:        &types.TypeMetadata{Type: metadataType},
			ExpectedVersion: twinVersion,
		}
		twin[dtwin.PropertyName] = msgTwin
	}
}

// deleteFromConfigMap deletes a device from configMap
func (dc *DownstreamController) deleteFromConfigMap(device *v1alpha1.Device) {
	if len(device.Spec.NodeSelector.NodeSelectorTerms) != 0 && len(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions) != 0 && len(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values) != 0 {
		configMap, ok := dc.configMapManager.ConfigMap.Load(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values[0])
		if !ok {
			return
		}
		nodeConfigMap, ok := configMap.(*v1.ConfigMap)
		if !ok {
			log.LOGGER.Errorf("Failed to assert to configmap")
			return
		}

		dc.deleteFromDeviceProfile(device, nodeConfigMap)

		// no device is bound to the configMap, then remove the configMap directly.
		if nodeConfigMap.Data[DeviceProfileJSON] == "{}" {
			deleteOptions := &metav1.DeleteOptions{}
			dc.kubeClient.CoreV1().ConfigMaps(device.Namespace).Delete(nodeConfigMap.Name, deleteOptions)
			// remove from cache
			dc.configMapManager.ConfigMap.Delete(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values[0])
			return
		}

		// store new config map
		dc.configMapManager.ConfigMap.Store(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values[0], nodeConfigMap)
		if _, err := dc.kubeClient.CoreV1().ConfigMaps(device.Namespace).Update(nodeConfigMap); err != nil {
			log.LOGGER.Errorf("Failed to update config map %v in namespace %v", nodeConfigMap, device.Namespace)
			return
		}
	}
}

// deleteFromDeviceProfile deletes a device from deviceProfile
func (dc *DownstreamController) deleteFromDeviceProfile(device *v1alpha1.Device, configMap *v1.ConfigMap) {
	dp, ok := configMap.Data[DeviceProfileJSON]
	if !ok {
		log.LOGGER.Errorf("Device profile does not exist in the configmap")
		return
	}

	deviceProfile := &types.DeviceProfile{}
	err := json.Unmarshal([]byte(dp), deviceProfile)
	if err != nil {
		log.LOGGER.Errorf("Failed to Unmarshal deviceprofile: %v", deviceProfile)
		return
	}
	deleteDeviceInstanceAndProtocol(device, deviceProfile)

	dm, ok := dc.deviceModelManager.DeviceModel.Load(device.Spec.DeviceModelRef.Name)
	if !ok {
		log.LOGGER.Errorf("Failed to get device model %v", device.Spec.DeviceModelRef.Name)
		return
	}
	deviceModel := dm.(*CacheDeviceModel)
	// if model referenced by other devices, no need to delete the model
	checkModelReferenced := false
	for _, dvc := range deviceProfile.DeviceInstances {
		if dvc.Model == deviceModel.Name {
			checkModelReferenced = true
			break
		}
	}
	if checkModelReferenced != true {
		deleteDeviceModelAndVisitors(deviceModel, deviceProfile)
	}
	bytes, err := json.Marshal(deviceProfile)
	if err != nil {
		log.LOGGER.Errorf("Failed to marshal deviceprofile: %v", deviceProfile)
		return
	}
	configMap.Data[DeviceProfileJSON] = string(bytes)
}

// deleteDeviceInstanceAndProtocol deletes deviceInstance and protocol from deviceProfile
func deleteDeviceInstanceAndProtocol(device *v1alpha1.Device, deviceProfile *types.DeviceProfile) {
	var protocol string
	for i, devInst := range deviceProfile.DeviceInstances {
		if device.Name == devInst.Name {
			protocol = devInst.Protocol
			deviceProfile.DeviceInstances[i] = deviceProfile.DeviceInstances[len(deviceProfile.DeviceInstances)-1]
			deviceProfile.DeviceInstances[len(deviceProfile.DeviceInstances)-1] = nil
			deviceProfile.DeviceInstances = deviceProfile.DeviceInstances[:len(deviceProfile.DeviceInstances)-1]
			break
		}
	}

	for i, ptcl := range deviceProfile.Protocols {
		if ptcl.Name == protocol {
			deviceProfile.Protocols[i] = deviceProfile.Protocols[len(deviceProfile.Protocols)-1]
			deviceProfile.Protocols[len(deviceProfile.Protocols)-1] = nil
			deviceProfile.Protocols = deviceProfile.Protocols[:len(deviceProfile.Protocols)-1]
			return
		}
	}
}

// deleteDeviceModelAndVisitors deletes deviceModel and visitor from deviceProfile
func deleteDeviceModelAndVisitors(deviceModel *CacheDeviceModel, deviceProfile *types.DeviceProfile) {
	for i, dm := range deviceProfile.DeviceModels {
		if dm.Name == deviceModel.Name {
			deviceProfile.DeviceModels[i] = deviceProfile.DeviceModels[len(deviceProfile.DeviceModels)-1]
			deviceProfile.DeviceModels[len(deviceProfile.DeviceModels)-1] = nil
			deviceProfile.DeviceModels = deviceProfile.DeviceModels[:len(deviceProfile.DeviceModels)-1]
			break
		}
	}

	allVisitorsNotDeleted := true
	for allVisitorsNotDeleted {
		allVisitorsNotDeleted = false
		for i, vst := range deviceProfile.PropertyVisitors {
			if vst.ModelName == deviceModel.Name {
				deviceProfile.PropertyVisitors[i] = deviceProfile.PropertyVisitors[len(deviceProfile.PropertyVisitors)-1]
				deviceProfile.PropertyVisitors[len(deviceProfile.PropertyVisitors)-1] = nil
				deviceProfile.PropertyVisitors = deviceProfile.PropertyVisitors[:len(deviceProfile.PropertyVisitors)-1]
				allVisitorsNotDeleted = true
				break
			}
		}
	}
}

// deviceDeleted send a deleted message to the edgeNode and deletes the device from the deviceManager.Device map
func (dc *DownstreamController) deviceDeleted(device *v1alpha1.Device) {
	dc.deviceManager.Device.Delete(device.Name)
	dc.deleteFromConfigMap(device)
	edgeDevice := createDevice(device)
	msg := model.NewMessage("")

	if len(device.Spec.NodeSelector.NodeSelectorTerms) != 0 && len(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions) != 0 && len(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values) != 0 {
		resource, err := messagelayer.BuildResource(device.Spec.NodeSelector.NodeSelectorTerms[0].MatchExpressions[0].Values[0], "membership", "")
		msg.BuildRouter(constants.DeviceControllerModuleName, constants.GroupTwin, resource, model.UpdateOperation)

		content := types.MembershipUpdate{RemoveDevices: []types.Device{
			edgeDevice,
		}}
		content.EventID = uuid.NewV4().String()
		content.Timestamp = time.Now().UnixNano() / 1e6
		msg.Content = content
		if err != nil {
			log.LOGGER.Warnf("Built message resource failed with error: %s", err)
			return
		}
		err = dc.messageLayer.Send(*msg)
		if err != nil {
			log.LOGGER.Errorf("Failed to send device addition message %v due to error %v", msg, err)
		}
	}
}

// Start DownstreamController
func (dc *DownstreamController) Start() error {
	log.LOGGER.Infof("Start downstream controller")

	dc.deviceModelStop = make(chan struct{})
	go dc.syncDeviceModel(dc.deviceModelStop)

	// Wait for adding all device model
	time.Sleep(1 * time.Second)
	dc.deviceStop = make(chan struct{})
	go dc.syncDevice(dc.deviceStop)

	return nil
}

// Stop DownstreamController
func (dc *DownstreamController) Stop() error {
	log.LOGGER.Infof("Stop downstream controller")
	dc.deviceStop <- struct{}{}
	dc.deviceModelStop <- struct{}{}
	return nil
}

// NewDownstreamController create a DownstreamController from config
func NewDownstreamController() (*DownstreamController, error) {
	/*lc := &manager.LocationCache{}*/

	cli, err := utils.KubeClient()
	if err != nil {
		log.LOGGER.Warnf("Create kube client failed with error: %s", err)
		return nil, err
	}

	config, err := utils.KubeConfig()
	if err != nil {
		log.LOGGER.Warnf("Get kubeConfig error: %v", err)
		return nil, err
	}

	crdcli, err := utils.NewCRDClient(config)
	deviceManager, err := manager.NewDeviceManager(crdcli, v1.NamespaceAll)
	if err != nil {
		log.LOGGER.Warnf("Create device manager failed with error: %s", err)
		return nil, err
	}

	deviceModelManager, err := manager.NewDeviceModelManager(crdcli, v1.NamespaceAll)
	if err != nil {
		log.LOGGER.Warnf("Create device manager failed with error: %s", err)
		return nil, err
	}

	cm := manager.NewConfigMapManager()

	ml, err := messagelayer.NewMessageLayer()
	if err != nil {
		log.LOGGER.Warnf("Create message layer failed with error: %s", err)
		return nil, err
	}

	dc := &DownstreamController{kubeClient: cli, deviceManager: deviceManager, deviceModelManager: deviceModelManager, messageLayer: ml, configMapManager: cm}
	return dc, nil
}