VOL-3344 - Enabled default linters and fixed found issues.

Also disabled govet's variable shadowing check, since this is very useful for isolating multiple "err"ors in a row.

Change-Id: Icd70c723c406c5986b8cfe4535ad7daa0752e48c
diff --git a/internal/pkg/core/openolt_eventmgr.go b/internal/pkg/core/openolt_eventmgr.go
index 6f1fd68..8a58303 100644
--- a/internal/pkg/core/openolt_eventmgr.go
+++ b/internal/pkg/core/openolt_eventmgr.go
@@ -45,8 +45,6 @@
 	onuSignalDegradeEvent               = "ONU_SIGNAL_DEGRADE"
 	onuDriftOfWindowEvent               = "ONU_DRIFT_OF_WINDOW"
 	onuActivationFailEvent              = "ONU_ACTIVATION_FAIL"
-	onuProcessingErrorEvent             = "ONU_PROCESSING_ERROR"
-	onuTiwiEvent                        = "ONU_TRANSMISSION_WARNING"
 	onuLossOmciEvent                    = "ONU_LOSS_OF_OMCI_CHANNEL"
 	onuLossOfKeySyncEvent               = "ONU_LOSS_OF_KEY_SYNC"
 	onuLossOfFrameEvent                 = "ONU_LOSS_OF_FRAME"
@@ -61,20 +59,6 @@
 )
 
 const (
-	pon           = voltha.EventSubCategory_PON
-	olt           = voltha.EventSubCategory_OLT
-	ont           = voltha.EventSubCategory_ONT
-	onu           = voltha.EventSubCategory_ONU
-	nni           = voltha.EventSubCategory_NNI
-	service       = voltha.EventCategory_SERVICE
-	security      = voltha.EventCategory_SECURITY
-	equipment     = voltha.EventCategory_EQUIPMENT
-	processing    = voltha.EventCategory_PROCESSING
-	environment   = voltha.EventCategory_ENVIRONMENT
-	communication = voltha.EventCategory_COMMUNICATION
-)
-
-const (
 	// statusCheckOn represents status check On
 	statusCheckOn = "on"
 	// statusCheckOff represents status check Off
@@ -134,7 +118,7 @@
 
 // ProcessEvents is function to process and publish OpenOLT event
 // nolint: gocyclo
-func (em *OpenOltEventMgr) ProcessEvents(ctx context.Context, alarmInd *oop.AlarmIndication, deviceID string, raisedTs int64) error {
+func (em *OpenOltEventMgr) ProcessEvents(ctx context.Context, alarmInd *oop.AlarmIndication, deviceID string, raisedTs int64) {
 	var err error
 	switch alarmInd.Data.(type) {
 	case *oop.AlarmIndication_LosInd:
@@ -192,9 +176,8 @@
 		err = olterrors.NewErrInvalidValue(log.Fields{"indication-type": alarmInd}, nil)
 	}
 	if err != nil {
-		return olterrors.NewErrCommunication("publish-message", log.Fields{"indication-type": alarmInd}, err).Log()
+		_ = olterrors.NewErrCommunication("publish-message", log.Fields{"indication-type": alarmInd}, err).LogAt(log.WarnLevel)
 	}
-	return nil
 }
 
 // oltUpDownIndication handles Up and Down state of an OLT
@@ -212,7 +195,7 @@
 		de.DeviceEventName = fmt.Sprintf("%s_%s", oltIndicationDown, "CLEAR_EVENT")
 	}
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, &de, communication, olt, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, &de, voltha.EventCategory_COMMUNICATION, voltha.EventSubCategory_OLT, raisedTs); err != nil {
 		return olterrors.NewErrCommunication("send-olt-event", log.Fields{"device-id": deviceID}, err)
 	}
 	logger.Debugw(ctx, "olt-updown-event-sent-to-kafka", log.Fields{})
@@ -233,7 +216,7 @@
 	de.ResourceId = oltDeviceID
 	de.DeviceEventName = fmt.Sprintf("%s_%s", onuDiscoveryEvent, "RAISE_EVENT")
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, &de, equipment, pon, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, &de, voltha.EventCategory_EQUIPMENT, voltha.EventSubCategory_PON, raisedTs); err != nil {
 		return olterrors.NewErrCommunication("send-onu-discovery-event",
 			log.Fields{
 				"serial-number": serialNumber,
@@ -282,7 +265,7 @@
 		de.DeviceEventName = fmt.Sprintf("%s_%s", oltLosEvent, "CLEAR_EVENT")
 	}
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, &de, communication, olt, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, &de, voltha.EventCategory_COMMUNICATION, voltha.EventSubCategory_OLT, raisedTs); err != nil {
 		return err
 	}
 	logger.Debugw(ctx, "olt-los-event-sent-to-kafka", log.Fields{"intf-id": oltLos.IntfId})
@@ -316,7 +299,7 @@
 	de.ResourceId = deviceID
 	de.DeviceEventName = fmt.Sprintf("%s_%s", onuDyingGaspEvent, "EVENT")
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, &de, communication, pon, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, &de, voltha.EventCategory_COMMUNICATION, voltha.EventSubCategory_PON, raisedTs); err != nil {
 		return err
 	}
 	logger.Debugw(ctx, "onu-dying-gasp-event-sent-to-kafka", log.Fields{"intf-id": dgi.IntfId})
@@ -433,7 +416,7 @@
 	}
 
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, &de, communication, onu, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, &de, voltha.EventCategory_COMMUNICATION, voltha.EventSubCategory_ONU, raisedTs); err != nil {
 		return err
 	}
 	logger.Debugw(ctx, "onu-los-event-sent-to-kafka", log.Fields{"onu-id": onuAlarm.OnuId, "intf-id": onuAlarm.IntfId})
@@ -455,7 +438,7 @@
 	de.ResourceId = deviceID
 	de.DeviceEventName = fmt.Sprintf("%s_%s", onuActivationFailEvent, "RAISE_EVENT")
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, &de, equipment, pon, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, &de, voltha.EventCategory_EQUIPMENT, voltha.EventSubCategory_PON, raisedTs); err != nil {
 		return err
 	}
 	logger.Debugw(ctx, "onu-activation-failure-event-sent-to-kafka", log.Fields{"onu-id": oaf.OnuId, "intf-id": oaf.IntfId})
@@ -480,7 +463,7 @@
 		de.DeviceEventName = fmt.Sprintf("%s_%s", onuLossOmciEvent, "CLEAR_EVENT")
 	}
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, &de, communication, pon, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, &de, voltha.EventCategory_COMMUNICATION, voltha.EventSubCategory_PON, raisedTs); err != nil {
 		return err
 	}
 	logger.Debugw(ctx, "onu-loss-of-omci-channel-event-sent-to-kafka", log.Fields{"onu-id": onuLossOmci.OnuId, "intf-id": onuLossOmci.IntfId})
@@ -507,7 +490,7 @@
 		de.DeviceEventName = fmt.Sprintf("%s_%s", onuDriftOfWindowEvent, "CLEAR_EVENT")
 	}
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, &de, communication, pon, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, &de, voltha.EventCategory_COMMUNICATION, voltha.EventSubCategory_PON, raisedTs); err != nil {
 		return err
 	}
 	logger.Debugw(ctx, "onu-drift-of-window-event-sent-to-kafka", log.Fields{"onu-id": onuDriftWindow.OnuId, "intf-id": onuDriftWindow.IntfId})
@@ -533,7 +516,7 @@
 		de.DeviceEventName = fmt.Sprintf("%s_%s", onuSignalDegradeEvent, "CLEAR_EVENT")
 	}
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, &de, communication, pon, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, &de, voltha.EventCategory_COMMUNICATION, voltha.EventSubCategory_PON, raisedTs); err != nil {
 		return err
 	}
 	logger.Debugw(ctx, "onu-signal-degrade-event-sent-to-kafka", log.Fields{"onu-id": onuSignalDegrade.OnuId, "intf-id": onuSignalDegrade.IntfId})
@@ -558,7 +541,7 @@
 		de.DeviceEventName = fmt.Sprintf("%s_%s", onuSignalsFailEvent, "CLEAR_EVENT")
 	}
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, &de, communication, pon, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, &de, voltha.EventCategory_COMMUNICATION, voltha.EventSubCategory_PON, raisedTs); err != nil {
 		return err
 	}
 	logger.Debugw(ctx, "onu-signals-fail-event-sent-to-kafka", log.Fields{"onu-id": onuSignalsFail.OnuId, "intf-id": onuSignalsFail.IntfId})
@@ -583,7 +566,7 @@
 		de.DeviceEventName = fmt.Sprintf("%s_%s", onuStartupFailEvent, "CLEAR_EVENT")
 	}
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, &de, communication, pon, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, &de, voltha.EventCategory_COMMUNICATION, voltha.EventSubCategory_PON, raisedTs); err != nil {
 		return err
 	}
 	logger.Debugw(ctx, "onu-startup-fail-event-sent-to-kafka", log.Fields{"onu-id": onuStartupFail.OnuId, "intf-id": onuStartupFail.IntfId})
@@ -608,7 +591,7 @@
 	}
 
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, &de, security, onu, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, &de, voltha.EventCategory_SECURITY, voltha.EventSubCategory_ONU, raisedTs); err != nil {
 		return err
 	}
 	logger.Debugw(ctx, "onu-loss-of-key-sync-event-sent-to-kafka", log.Fields{"onu-id": onuLOKI.OnuId, "intf-id": onuLOKI.IntfId})
@@ -616,13 +599,13 @@
 }
 
 // oltIntfOperIndication handles Up and Down state of an OLT PON ports
-func (em *OpenOltEventMgr) oltIntfOperIndication(ctx context.Context, ifindication *oop.IntfOperIndication, deviceID string, raisedTs int64) error {
+func (em *OpenOltEventMgr) oltIntfOperIndication(ctx context.Context, ifindication *oop.IntfOperIndication, deviceID string, raisedTs int64) {
 	portNo := IntfIDToPortNo(ifindication.IntfId, voltha.Port_PON_OLT)
 	if port, err := em.handler.coreProxy.GetDevicePort(ctx, deviceID, portNo); err != nil {
 		logger.Warnw(ctx, "Error while fetching port object", log.Fields{"device-id": deviceID, "error": err})
 	} else if port.AdminState != common.AdminState_ENABLED {
 		logger.Debugw(ctx, "port-disable/enable-event-not-generated--the-port-is-not-enabled-by-operator", log.Fields{"device-id": deviceID, "port": port})
-		return nil
+		return
 	}
 	/* Populating event context */
 	context := map[string]string{ContextOltPonIntfOperState: ifindication.GetOperState()}
@@ -637,11 +620,11 @@
 		de.DeviceEventName = fmt.Sprintf("%s_%s", ponIntfDownIndiction, "CLEAR_EVENT")
 	}
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, &de, communication, olt, raisedTs); err != nil {
-		return olterrors.NewErrCommunication("send-olt-intf-oper-status-event", log.Fields{"device-id": deviceID, "intf-id": ifindication.IntfId, "oper-state": ifindication.OperState}, err).Log()
+	if err := em.eventProxy.SendDeviceEvent(ctx, &de, voltha.EventCategory_COMMUNICATION, voltha.EventSubCategory_OLT, raisedTs); err != nil {
+		_ = olterrors.NewErrCommunication("send-olt-intf-oper-status-event", log.Fields{"device-id": deviceID, "intf-id": ifindication.IntfId, "oper-state": ifindication.OperState}, err).LogAt(log.WarnLevel)
+		return
 	}
 	logger.Debug(ctx, "sent-olt-intf-oper-status-event-to-kafka")
-	return nil
 }
 
 func (em *OpenOltEventMgr) onuDeactivationFailureIndication(ctx context.Context, onuDFI *oop.OnuDeactivationFailureIndication, deviceID string, raisedTs int64) error {
@@ -661,7 +644,7 @@
 		de.DeviceEventName = fmt.Sprintf("%s_%s", onuDeactivationFailureEvent, "CLEAR_EVENT")
 	}
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, &de, equipment, onu, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, &de, voltha.EventCategory_EQUIPMENT, voltha.EventSubCategory_ONU, raisedTs); err != nil {
 		return err
 	}
 	logger.Debugw(ctx, "onu-deactivation-failure-event-sent-to-kafka", log.Fields{"onu-id": onuDFI.OnuId, "intf-id": onuDFI.IntfId})
@@ -688,7 +671,7 @@
 		de.DeviceEventName = fmt.Sprintf("%s_%s", onuRemoteDefectIndication, "CLEAR_EVENT")
 	}
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, de, equipment, onu, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, de, voltha.EventCategory_EQUIPMENT, voltha.EventSubCategory_ONU, raisedTs); err != nil {
 		return err
 	}
 	logger.Debugw(ctx, "onu-remote-defect-event-sent-to-kafka", log.Fields{"onu-id": onuID, "intf-id": intfID})
@@ -738,7 +721,7 @@
 		de.DeviceEventName = fmt.Sprintf("%s_%s", onuLossOfGEMChannelDelineationEvent, "CLEAR_EVENT")
 	}
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, de, communication, onu, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, de, voltha.EventCategory_COMMUNICATION, voltha.EventSubCategory_ONU, raisedTs); err != nil {
 		return err
 	}
 	logger.Debugw(ctx, "onu-loss-of-gem-channel-delineation-event-sent-to-kafka", log.Fields{"onu-id": onuGCD.OnuId, "intf-id": onuGCD.IntfId})
@@ -763,7 +746,7 @@
 		de.DeviceEventName = fmt.Sprintf("%s_%s", onuPhysicalEquipmentErrorEvent, "CLEAR_EVENT")
 	}
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, de, equipment, onu, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, de, voltha.EventCategory_EQUIPMENT, voltha.EventSubCategory_ONU, raisedTs); err != nil {
 		return err
 	}
 	logger.Debugw(ctx, "onu-physical-equipment-error-event-sent-to-kafka", log.Fields{"onu-id": onuErr.OnuId, "intf-id": onuErr.IntfId})
@@ -789,7 +772,7 @@
 		de.DeviceEventName = fmt.Sprintf("%s_%s", onuLossOfAcknowledgementEvent, "CLEAR_EVENT")
 	}
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, de, equipment, onu, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, de, voltha.EventCategory_EQUIPMENT, voltha.EventSubCategory_ONU, raisedTs); err != nil {
 		return err
 	}
 	logger.Debugw(ctx, "onu-physical-equipment-error-event-sent-to-kafka", log.Fields{"onu-id": onuLOA.OnuId, "intf-id": onuLOA.IntfId})
@@ -816,7 +799,7 @@
 		de.DeviceEventName = fmt.Sprintf("%s_%s", onuDifferentialReachExceededEvent, "CLEAR_EVENT")
 	}
 	/* Send event to KAFKA */
-	if err := em.eventProxy.SendDeviceEvent(ctx, de, equipment, onu, raisedTs); err != nil {
+	if err := em.eventProxy.SendDeviceEvent(ctx, de, voltha.EventCategory_EQUIPMENT, voltha.EventSubCategory_ONU, raisedTs); err != nil {
 		return err
 	}
 	log.Debugw("onu-differential-reach-exceeded–event-sent-to-kafka", log.Fields{"onu-id": onuDRE.OnuId, "intf-id": onuDRE.IntfId})