feat: Allow purging events

cmd/core-data/res/configuration.yaml

@@ -8,6 +8,7 @@ Writable:
       ReadingsPersisted: false
 #    Tags: # Contains the service level tags to be attached to all the service's metrics
     ##    Gateway="my-iot-gateway" # Tag must be added here or via Consul Env Override can only change existing value, not added new ones.
+  EventPurge: false # Remove the related events and readings once received the device deletion system event
 
 Service:
   Port: 59880

internal/core/data/config/config.go

@@ -34,6 +34,7 @@ type WritableInfo struct {
 	LogLevel        string
 	InsecureSecrets bootstrapConfig.InsecureSecrets
 	Telemetry       bootstrapConfig.TelemetryInfo
+	EventPurge      bool
 }
 
 type ReadingRetention struct {

internal/core/data/controller/messaging/system_event.go

@@ -0,0 +1,101 @@
+//
+// Copyright (C) 2025 IOTech Ltd
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package messaging
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	"github.com/edgexfoundry/edgex-go/internal/core/data/application"
+	dataContainer "github.com/edgexfoundry/edgex-go/internal/core/data/container"
+	bootstrapContainer "github.com/edgexfoundry/go-mod-bootstrap/v4/bootstrap/container"
+	"github.com/edgexfoundry/go-mod-bootstrap/v4/di"
+	"github.com/edgexfoundry/go-mod-core-contracts/v4/common"
+	"github.com/edgexfoundry/go-mod-core-contracts/v4/dtos"
+	"github.com/edgexfoundry/go-mod-core-contracts/v4/errors"
+	"github.com/edgexfoundry/go-mod-messaging/v4/pkg/types"
+)
+
+func SubscribeSystemEvents(ctx context.Context, dic *di.Container) errors.EdgeX {
+	lc := bootstrapContainer.LoggingClientFrom(dic.Get)
+	configuration := dataContainer.ConfigurationFrom(dic.Get)
+	messageBusInfo := dataContainer.ConfigurationFrom(dic.Get).MessageBus
+
+	// device deletion event edgex/system-events/core-metadata/device/delete/<device name>/<device profile name>
+	deviceDeletionSystemEventTopic := common.NewPathBuilder().EnableNameFieldEscape(configuration.Service.EnableNameFieldEscape).
+		SetPath(messageBusInfo.GetBaseTopicPrefix()).SetPath(common.SystemEventPublishTopic).SetPath(common.CoreMetaDataServiceKey).
+		SetPath(common.DeviceSystemEventType).SetPath(common.SystemEventActionDelete).SetPath("#").BuildPath()
+	lc.Infof("Subscribing to System Events on topic: %s", deviceDeletionSystemEventTopic)
+
+	messages := make(chan types.MessageEnvelope, 1)
+	messageErrors := make(chan error, 1)
+	topics := []types.TopicChannel{
+		{
+			Topic:    deviceDeletionSystemEventTopic,
+			Messages: messages,
+		},
+	}
+
+	messageBus := bootstrapContainer.MessagingClientFrom(dic.Get)
+	err := messageBus.Subscribe(topics, messageErrors)
+	if err != nil {
+		return errors.NewCommonEdgeXWrapper(err)
+	}
+
+	go func() {
+		for {
+			select {
+			case <-ctx.Done():
+				lc.Infof("Exiting waiting for MessageBus '%s' topic messages", deviceDeletionSystemEventTopic)
+				return
+			case err = <-messageErrors:
+				lc.Error(err.Error())
+			case msgEnvelope := <-messages:
+				lc.Debugf("System event received on message queue. Topic: %s, Correlation-id: %s", msgEnvelope.ReceivedTopic, msgEnvelope.CorrelationID)
+				var systemEvent dtos.SystemEvent
+				err := json.Unmarshal(msgEnvelope.Payload, &systemEvent)
+				if err != nil {
+					lc.Errorf("failed to JSON decoding system event: %s", err.Error())
+					continue
+				}
+
+				switch systemEvent.Type {
+				case common.DeviceSystemEventType:
+					err = deviceSystemEventAction(systemEvent, dic)
+					if err != nil {
+						lc.Error(err.Error(), common.CorrelationHeader, msgEnvelope.CorrelationID)
+					}
+				}
+			}
+		}
+	}()
+
+	return nil
+}
+
+func deviceSystemEventAction(systemEvent dtos.SystemEvent, dic *di.Container) error {
+	var device dtos.Device
+	err := systemEvent.DecodeDetails(&device)
+	if err != nil {
+		return fmt.Errorf("failed to decode %s system event details: %s", systemEvent.Type, err.Error())
+	}
+
+	lc := bootstrapContainer.LoggingClientFrom(dic.Get)
+	switch systemEvent.Action {
+	case common.SystemEventActionDelete:
+		if !dataContainer.ConfigurationFrom(dic.Get).Writable.EventPurge {
+			return nil
+		}
+		lc.Debugf("Device '%s' is deleted, try to remove related events and readings.", device.Name)
+		err = application.CoreDataAppFrom(dic.Get).DeleteEventsByDeviceName(device.Name, dic)
+		if err != nil {
+			return errors.NewCommonEdgeXWrapper(err)
+		}
+		lc.Debugf("Events and readings are removed for the Device '%s'.", device.Name)
+	}
+	return nil
+}

internal/core/data/init.go

@@ -55,6 +55,11 @@ func (b *Bootstrap) BootstrapHandler(ctx context.Context, wg *sync.WaitGroup, st
 		lc.Errorf("Failed to subscribe events from message bus, %v", err)
 		return false
 	}
+	err = messaging.SubscribeSystemEvents(ctx, dic)
+	if err != nil {
+		lc.Errorf("Failed to subscribe system events from message bus, %v", err)
+		return false
+	}
 
 	config := container.ConfigurationFrom(dic.Get)
 	if config.Retention.Enabled {