feat(inputs.opcua_listener): Allow to subscribe to OPCUA events (#16532)

Co-authored-by: Sven Rebhan <srebhan@influxdata.com>

plugins/common/opcua/input/input_client.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/gopcua/opcua/id"
 	"github.com/gopcua/opcua/ua"
 
 	"github.com/influxdata/telegraf"
@@ -75,6 +76,80 @@ type NodeGroupSettings struct {
 	SamplingInterval config.Duration   `toml:"sampling_interval"` // Can be overridden by monitoring parameters
 }
 
+type EventNodeSettings struct {
+	Namespace      string `toml:"namespace"`
+	IdentifierType string `toml:"identifier_type"`
+	Identifier     string `toml:"identifier"`
+}
+
+func (e *EventNodeSettings) NodeID() string {
+	return "ns=" + e.Namespace + ";" + e.IdentifierType + "=" + e.Identifier
+}
+
+type EventGroupSettings struct {
+	SamplingInterval config.Duration     `toml:"sampling_interval"`
+	QueueSize        uint32              `toml:"queue_size"`
+	EventTypeNode    EventNodeSettings   `toml:"event_type_node"`
+	Namespace        string              `toml:"namespace"`
+	IdentifierType   string              `toml:"identifier_type"`
+	NodeIDSettings   []EventNodeSettings `toml:"node_ids"`
+	SourceNames      []string            `toml:"source_names"`
+	Fields           []string            `toml:"fields"`
+}
+
+func (e *EventGroupSettings) UpdateNodeIDSettings() {
+	for i := range e.NodeIDSettings {
+		n := &e.NodeIDSettings[i]
+		if n.Namespace == "" {
+			n.Namespace = e.Namespace
+		}
+		if n.IdentifierType == "" {
+			n.IdentifierType = e.IdentifierType
+		}
+	}
+}
+
+func (e *EventGroupSettings) Validate() error {
+	if err := e.EventTypeNode.validateEventNodeSettings(); err != nil {
+		return fmt.Errorf("invalid event_type_node_settings: %w", err)
+	}
+
+	if len(e.NodeIDSettings) == 0 {
+		return errors.New("at least one node_id must be specified")
+	}
+
+	for _, node := range e.NodeIDSettings {
+		if err := node.validateEventNodeSettings(); err != nil {
+			return fmt.Errorf("invalid node_id_settings: %w", err)
+		}
+	}
+
+	if len(e.Fields) == 0 {
+		return errors.New("at least one Field must be specified")
+	}
+	for _, field := range e.Fields {
+		if field == "" {
+			return errors.New("empty field name in fields stanza")
+		}
+	}
+	return nil
+}
+
+func (e EventNodeSettings) validateEventNodeSettings() error {
+	var defaultNodeSettings EventNodeSettings
+	if e == defaultNodeSettings {
+		return errors.New("node settings can't be empty")
+	}
+	if e.Identifier == "" {
+		return errors.New("identifier must be set")
+	} else if e.IdentifierType == "" {
+		return errors.New("identifier_type must be set")
+	} else if e.Namespace == "" {
+		return errors.New("namespace must be set")
+	}
+	return nil
+}
+
 type TimestampSource string
 
 const (
@@ -86,11 +161,12 @@ const (
 // InputClientConfig a configuration for the input client
 type InputClientConfig struct {
 	opcua.OpcUAClientConfig
-	MetricName      string              `toml:"name"`
+	MetricName      string               `toml:"name"`
-	Timestamp       TimestampSource     `toml:"timestamp"`
+	Timestamp       TimestampSource      `toml:"timestamp"`
-	TimestampFormat string              `toml:"timestamp_format"`
+	TimestampFormat string               `toml:"timestamp_format"`
-	RootNodes       []NodeSettings      `toml:"nodes"`
+	RootNodes       []NodeSettings       `toml:"nodes"`
-	Groups          []NodeGroupSettings `toml:"group"`
+	Groups          []NodeGroupSettings  `toml:"group"`
+	EventGroups     []EventGroupSettings `toml:"events"`
 }
 
 func (o *InputClientConfig) Validate() error {
@@ -107,8 +183,8 @@ func (o *InputClientConfig) Validate() error {
 		o.TimestampFormat = time.RFC3339Nano
 	}
 
-	if len(o.Groups) == 0 && len(o.RootNodes) == 0 {
+	if len(o.Groups) == 0 && len(o.RootNodes) == 0 && o.EventGroups == nil {
-		return errors.New("no groups or root nodes provided to gather from")
+		return errors.New("no groups, root nodes or events provided to gather from")
 	}
 	for _, group := range o.Groups {
 		if len(group.Nodes) == 0 {
@@ -124,6 +200,15 @@ func (o *InputClientConfig) CreateInputClient(log telegraf.Logger) (*OpcUAInputC
 		return nil, err
 	}
 
+	if o.EventGroups != nil {
+		for _, eventGroup := range o.EventGroups {
+			eventGroup.UpdateNodeIDSettings()
+			if err := eventGroup.Validate(); err != nil {
+				return nil, fmt.Errorf("invalid event_settings: %w", err)
+			}
+		}
+	}
+
 	log.Debug("Initialising OpcUAInputClient")
 	opcClient, err := o.OpcUAClientConfig.CreateClient(log)
 	if err != nil {
@@ -134,6 +219,7 @@ func (o *InputClientConfig) CreateInputClient(log telegraf.Logger) (*OpcUAInputC
 		OpcUAClient: opcClient,
 		Log:         log,
 		Config:      *o,
+		EventGroups: o.EventGroups,
 	}
 
 	log.Debug("Initialising node to metric mapping")
@@ -185,6 +271,15 @@ func NewNodeMetricMapping(metricName string, node NodeSettings, groupTags map[st
 	}, nil
 }
 
+type EventNodeMetricMapping struct {
+	NodeID           *ua.NodeID
+	SamplingInterval *config.Duration
+	QueueSize        *uint32
+	EventTypeNode    *ua.NodeID
+	SourceNames      []string
+	Fields           []string
+}
+
 // NodeValue The received value for a node
 type NodeValue struct {
 	TagName    string
@@ -203,9 +298,11 @@ type OpcUAInputClient struct {
 	Config InputClientConfig
 	Log    telegraf.Logger
 
-	NodeMetricMapping []NodeMetricMapping
+	NodeMetricMapping      []NodeMetricMapping
-	NodeIDs           []*ua.NodeID
+	NodeIDs                []*ua.NodeID
-	LastReceivedData  []NodeValue
+	LastReceivedData       []NodeValue
+	EventGroups            []EventGroupSettings
+	EventNodeMetricMapping []EventNodeMetricMapping
 }
 
 // Stop the connection to the client
@@ -381,6 +478,33 @@ func (o *OpcUAInputClient) InitNodeIDs() error {
 	return nil
 }
 
+func (o *OpcUAInputClient) InitEventNodeIDs() error {
+	for _, eventSetting := range o.EventGroups {
+		eid, err := ua.ParseNodeID(eventSetting.EventTypeNode.NodeID())
+		if err != nil {
+			return err
+		}
+		for _, node := range eventSetting.NodeIDSettings {
+			nid, err := ua.ParseNodeID(node.NodeID())
+
+			if err != nil {
+				return err
+			}
+			nmm := EventNodeMetricMapping{
+				NodeID:           nid,
+				SamplingInterval: &eventSetting.SamplingInterval,
+				QueueSize:        &eventSetting.QueueSize,
+				EventTypeNode:    eid,
+				SourceNames:      eventSetting.SourceNames,
+				Fields:           eventSetting.Fields,
+			}
+			o.EventNodeMetricMapping = append(o.EventNodeMetricMapping, nmm)
+		}
+	}
+
+	return nil
+}
+
 func (o *OpcUAInputClient) initLastReceivedValues() {
 	o.LastReceivedData = make([]NodeValue, len(o.NodeMetricMapping))
 	for nodeIdx, nmm := range o.NodeMetricMapping {
@@ -448,3 +572,151 @@ func (o *OpcUAInputClient) MetricForNode(nodeIdx int) telegraf.Metric {
 
 	return metric.New(nmm.metricName, tags, fields, t)
 }
+
+func (o *OpcUAInputClient) MetricForEvent(nodeIdx int, event *ua.EventFieldList) telegraf.Metric {
+	node := o.EventNodeMetricMapping[nodeIdx]
+	fields := make(map[string]interface{}, len(event.EventFields))
+	for i, field := range event.EventFields {
+		name := node.Fields[i]
+		value := field.Value()
+
+		if value == nil {
+			o.Log.Warnf("Field %s has no value", name)
+			continue
+		}
+
+		switch v := value.(type) {
+		case *ua.LocalizedText:
+			fields[name] = v.Text
+		case time.Time:
+			fields[name] = v.Format(time.RFC3339)
+		default:
+			fields[name] = v
+		}
+	}
+	tags := map[string]string{
+		"node_id": node.NodeID.String(),
+		"source":  o.Config.Endpoint,
+	}
+	var t time.Time
+	switch o.Config.Timestamp {
+	case TimestampSourceServer:
+		t = o.LastReceivedData[nodeIdx].ServerTime
+	case TimestampSourceSource:
+		t = o.LastReceivedData[nodeIdx].SourceTime
+	default:
+		t = time.Now()
+	}
+
+	return metric.New("opcua_event", tags, fields, t)
+}
+
+// Creation of event filter for event streaming
+func (node *EventNodeMetricMapping) CreateEventFilter() (*ua.ExtensionObject, error) {
+	selects, err := node.createSelectClauses()
+	if err != nil {
+		return nil, err
+	}
+	wheres, err := node.createWhereClauses()
+	if err != nil {
+		return nil, err
+	}
+	return &ua.ExtensionObject{
+		EncodingMask: ua.ExtensionObjectBinary,
+		TypeID:       &ua.ExpandedNodeID{NodeID: ua.NewNumericNodeID(0, id.EventFilter_Encoding_DefaultBinary)},
+		Value: ua.EventFilter{
+			SelectClauses: selects,
+			WhereClause:   wheres,
+		},
+	}, nil
+}
+
+func (node *EventNodeMetricMapping) createSelectClauses() ([]*ua.SimpleAttributeOperand, error) {
+	selects := make([]*ua.SimpleAttributeOperand, len(node.Fields))
+	typeDefinition, err := node.determineNodeIDType()
+	if err != nil {
+		return nil, err
+	}
+	for i, name := range node.Fields {
+		selects[i] = &ua.SimpleAttributeOperand{
+			TypeDefinitionID: typeDefinition,
+			BrowsePath:       []*ua.QualifiedName{{NamespaceIndex: 0, Name: name}},
+			AttributeID:      ua.AttributeIDValue,
+		}
+	}
+	return selects, nil
+}
+
+func (node *EventNodeMetricMapping) createWhereClauses() (*ua.ContentFilter, error) {
+	if len(node.SourceNames) == 0 {
+		return &ua.ContentFilter{
+			Elements: make([]*ua.ContentFilterElement, 0),
+		}, nil
+	}
+	operands := make([]*ua.ExtensionObject, 0)
+	for _, sourceName := range node.SourceNames {
+		literalOperand := &ua.ExtensionObject{
+			EncodingMask: 1,
+			TypeID: &ua.ExpandedNodeID{
+				NodeID: ua.NewNumericNodeID(0, id.LiteralOperand_Encoding_DefaultBinary),
+			},
+			Value: ua.LiteralOperand{
+				Value: ua.MustVariant(sourceName),
+			},
+		}
+		operands = append(operands, literalOperand)
+	}
+
+	typeDefinition, err := node.determineNodeIDType()
+	if err != nil {
+		return nil, err
+	}
+
+	attributeOperand := &ua.ExtensionObject{
+		EncodingMask: ua.ExtensionObjectBinary,
+		TypeID: &ua.ExpandedNodeID{
+			NodeID: ua.NewNumericNodeID(0, id.SimpleAttributeOperand_Encoding_DefaultBinary),
+		},
+		Value: &ua.SimpleAttributeOperand{
+			TypeDefinitionID: typeDefinition,
+			BrowsePath: []*ua.QualifiedName{
+				{NamespaceIndex: 0, Name: "SourceName"},
+			},
+			AttributeID: ua.AttributeIDValue,
+		},
+	}
+
+	filterElement := &ua.ContentFilterElement{
+		FilterOperator: ua.FilterOperatorInList,
+		FilterOperands: append([]*ua.ExtensionObject{attributeOperand}, operands...),
+	}
+
+	wheres := &ua.ContentFilter{
+		Elements: []*ua.ContentFilterElement{filterElement},
+	}
+
+	return wheres, nil
+}
+
+func (node *EventNodeMetricMapping) determineNodeIDType() (*ua.NodeID, error) {
+	switch node.EventTypeNode.Type() {
+	case ua.NodeIDTypeGUID:
+		return ua.NewGUIDNodeID(node.EventTypeNode.Namespace(), node.EventTypeNode.StringID()), nil
+	case ua.NodeIDTypeString:
+		return ua.NewStringNodeID(node.EventTypeNode.Namespace(), node.EventTypeNode.StringID()), nil
+	case ua.NodeIDTypeByteString:
+		return ua.NewByteStringNodeID(node.EventTypeNode.Namespace(), []byte(node.EventTypeNode.StringID())), nil
+	case ua.NodeIDTypeTwoByte:
+		nodeID := node.EventTypeNode.IntID()
+		if nodeID > 255 {
+			return nil, fmt.Errorf("twoByte EventType requires a value in the range 0-255, got %d", nodeID)
+		}
+		return ua.NewTwoByteNodeID(uint8(node.EventTypeNode.IntID())), nil
+	case ua.NodeIDTypeFourByte:
+		return ua.NewFourByteNodeID(uint8(node.EventTypeNode.Namespace()), uint16(node.EventTypeNode.IntID())), nil
+	case ua.NodeIDTypeNumeric:
+		return ua.NewNumericNodeID(node.EventTypeNode.Namespace(), node.EventTypeNode.IntID()), nil
+	default:
+		return nil, fmt.Errorf("unsupported NodeID type: %v", node.EventTypeNode.String())
+	}
+}

plugins/inputs/opcua_listener/README.md

@@ -1,9 +1,13 @@
 # OPC UA Client Listener Input Plugin
 
-The `opcua_listener` plugin subscribes to data from OPC UA Server devices.
+This service plugin subscribes to data and events from an [OPC UA][opcua]
+erver.
 
-Telegraf minimum version: Telegraf 1.25
+⭐ Telegraf v1.25.0
-Plugin minimum tested version: 1.25
+🏷️ network
+💻 linux, windows
+
+[opcua]: https://opcfoundation.org/
 
 ## Service Input <!-- @/docs/includes/service_input.md -->
 
@@ -250,17 +254,42 @@ to use them.
   #       deadband_value = 0.0
   #
 
+  ## Multiple event groups are allowed.
+  # [[inputs.opcua_listener.events]]
+  #   ## Polling interval for data collection
+  #   # sampling_interval = "10s"
+  #   ## Size of the notification queue
+  #   # queue_size = 10
+  #   ## Node parameter defaults for node definitions below
+  #   # namespace = ""
+  #   # identifier_type = ""
+  #   ## Specifies OPCUA Event sources to filter on
+  #   # source_names = ["SourceName1", "SourceName2"]
+  #   ## Fields to capture from event notifications
+  #   fields = ["Severity", "Message", "Time"]
+  #
+  #   ## Type or level of events to capture from the monitored nodes.
+  #   [inputs.opcua_listener.events.event_type_node]
+  #     namespace = ""
+  #     identifier_type = ""
+  #     identifier = ""
+  #
+  #   ## Nodes to monitor for event notifications associated with the defined
+  #   ## event type
+  #   [[inputs.opcua_listener.events.node_ids]]
+  #     namespace = ""
+  #     identifier_type = ""
+  #     identifier = ""
+
   ## Enable workarounds required by some devices to work correctly
   # [inputs.opcua_listener.workarounds]
-    ## Set additional valid status codes, StatusOK (0x0) is always considered valid
+  #  ## Set additional valid status codes, StatusOK (0x0) is always considered valid
-    # additional_valid_status_codes = ["0xC0"]
+  #  # additional_valid_status_codes = ["0xC0"]
-
+  #  ## Use unregistered reads instead of registered reads
-  # [inputs.opcua_listener.request_workarounds]
+  #  # use_unregistered_reads = false
-    ## Use unregistered reads instead of registered reads
-    # use_unregistered_reads = false
 ```
 
-## Node Configuration
+### Node Configuration
 
 An OPC UA node ID may resemble: "ns=3;s=Temperature". In this example:
 
@@ -286,7 +315,7 @@ produces a metric like this:
 opcua,id=ns\=3;s\=Temperature temp=79.0,Quality="OK (0x0)",DataType="Float" 1597820490000000000
 ```
 
-## Group Configuration
+#### Group Configuration
 
 Groups can set default values for the namespace, identifier type, tags
 settings and sampling interval.  The default values apply to all the
@@ -342,16 +371,68 @@ This example group configuration has three groups with two nodes each:
     ]
 ```
 
-## Connection Service
+### Event Configuration
 
-This plugin subscribes to the specified nodes to receive data from
+Defining events allows subscribing to events with the specific node IDs and
-the OPC server. The updates are received at most as fast as the
+filtering criteria based on the event type and source. The plugin subscribes to
-`subscription_interval`.
+the specified `event_type` Node-IDs and collects events that meet the defined
+criteria. The `node_ids` parameter specifies the nodes to monitor for events
+(monitored items). However, the actual subscription is based on the
+`event_type_node` determining the events to capture.
+
+#### Event Group Configuration
+
+You can define multiple groups for the event streaming to subscribe to different
+event types. Each group allows to specify defaults for `namespace` and
+`identifier_type` being overwritten by settings in `node_ids`. The group
+defaults for node information will not affected the `event_type_node` setting
+and all paramters must be set in this section.
+
+This example group configuration shows how to use group settings:
+
+```toml
+# Group 1
+[[inputs.opcua_listener.events]]
+   sampling_interval = "10s"
+   queue_size = "100"
+   source_names = ["SourceName1", "SourceName2"]
+   fields = ["Severity", "Message", "Time"]
+
+   [inputs.opcua_listener.events.event_type_node]
+     namespace = "1"
+     identifier_type = "i"
+     identifier = "1234"
+
+   [[inputs.opcua_listener.events.node_ids]]
+     namespace = "2"
+     identifier_type = "i"
+     identifier = "2345"
+
+# Group 2
+[[inputs.opcua_listener.events]]
+   sampling_interval = "10s"
+   queue_size = "100"
+   namespace = "3"
+   identifier_type = "s"
+   source_names = ["SourceName1", "SourceName2"]
+   fields = ["Severity", "Message", "Time"]
+
+   [inputs.opcua_listener.events.event_type_node]
+     namespace = "1"
+     identifier_type = "i"
+     identifier = "5678"
+
+    node_ids = [
+      {identifier="Sensor1"}, // default values will be used for namespace and identifier_type
+      {namespace="2", identifier="TemperatureSensor"}, // default values will be used for identifier_type
+      {namespace="5", identifier_type="i", identifier="2002"} // no default values will be used
+    ]
+```
 
 ## Metrics
 
-The metrics collected by this input plugin will depend on the
+The metrics collected by this input plugin will depend on the configured
-configured `nodes` and `group`.
+`nodes`, `events` and the corresponding groups.
 
 ## Example Output
 

plugins/inputs/opcua_listener/opcua_listener.go

@@ -64,7 +64,7 @@ func (o *OpcUaListener) Stop() {
 
 func (o *OpcUaListener) connect(acc telegraf.Accumulator) error {
 	ctx := context.Background()
-	ch, err := o.client.startStreamValues(ctx)
+	ch, err := o.client.startMonitoring(ctx)
 	if err != nil {
 		return err
 	}

plugins/inputs/opcua_listener/opcua_listener_test.go

@@ -193,7 +193,7 @@ func TestSubscribeClientIntegration(t *testing.T) {
 
 	ctx, cancel := context.WithTimeout(t.Context(), time.Second*10)
 	defer cancel()
-	res, err := o.startStreamValues(ctx)
+	res, err := o.startMonitoring(ctx)
 	require.Equal(t, opcua.Connected, o.State())
 	require.NoError(t, err)
 
@@ -336,7 +336,7 @@ func TestSubscribeClientIntegrationAdditionalFields(t *testing.T) {
 
 	ctx, cancel := context.WithTimeout(t.Context(), time.Second*10)
 	defer cancel()
-	res, err := o.startStreamValues(ctx)
+	res, err := o.startMonitoring(ctx)
 	require.NoError(t, err)
 
 	for {
@@ -814,3 +814,482 @@ func TestSubscribeClientConfigValidMonitoringParams(t *testing.T) {
 		),
 	}, subClient.monitoredItemsReqs[0].RequestedParameters)
 }
+
+func TestSubscribeClientConfigValidMonitoringAndEventParams(t *testing.T) {
+	subscribeConfig := subscribeClientConfig{
+		InputClientConfig: input.InputClientConfig{
+			OpcUAClientConfig: opcua.OpcUAClientConfig{
+				Endpoint:       "opc.tcp://localhost:4840",
+				SecurityPolicy: "None",
+				SecurityMode:   "None",
+				AuthMethod:     "Anonymous",
+				ConnectTimeout: config.Duration(10 * time.Second),
+				RequestTimeout: config.Duration(1 * time.Second),
+				Workarounds:    opcua.OpcUAWorkarounds{},
+			},
+			MetricName:  "testing",
+			RootNodes:   make([]input.NodeSettings, 0),
+			Groups:      make([]input.NodeGroupSettings, 0),
+			EventGroups: make([]input.EventGroupSettings, 0),
+		},
+		SubscriptionInterval: 0,
+	}
+
+	var queueSize uint32 = 10
+	discardOldest := true
+	deadbandValue := 10.0
+	subscribeConfig.RootNodes = append(subscribeConfig.RootNodes, input.NodeSettings{
+		FieldName:      "foo",
+		Namespace:      "3",
+		Identifier:     "1",
+		IdentifierType: "i",
+		MonitoringParams: input.MonitoringParameters{
+			SamplingInterval: 50000000,
+			QueueSize:        &queueSize,
+			DiscardOldest:    &discardOldest,
+			DataChangeFilter: &input.DataChangeFilter{
+				Trigger:       "Status",
+				DeadbandType:  "Absolute",
+				DeadbandValue: &deadbandValue,
+			},
+		},
+	})
+	subscribeConfig.EventGroups = append(subscribeConfig.EventGroups, input.EventGroupSettings{
+		SamplingInterval: 1.0,
+		EventTypeNode: input.EventNodeSettings{
+			Namespace:      "3",
+			IdentifierType: "i",
+			Identifier:     "1234",
+		},
+		Namespace:      "3",
+		IdentifierType: "i",
+		NodeIDSettings: []input.EventNodeSettings{
+			{
+				Namespace:      "3",
+				IdentifierType: "i",
+				Identifier:     "12",
+			},
+			{
+				Namespace:      "3",
+				IdentifierType: "i",
+				Identifier:     "13",
+			},
+		},
+		SourceNames: []string{"SensorXYZ"},
+		Fields:      []string{"PressureValue"},
+	})
+
+	subClient, err := subscribeConfig.createSubscribeClient(testutil.Logger{})
+	require.NoError(t, err)
+	require.Equal(t, &ua.MonitoringParameters{
+		SamplingInterval: 50,
+		QueueSize:        queueSize,
+		DiscardOldest:    discardOldest,
+		Filter: ua.NewExtensionObject(
+			&ua.DataChangeFilter{
+				Trigger:       ua.DataChangeTriggerStatus,
+				DeadbandType:  uint32(ua.DeadbandTypeAbsolute),
+				DeadbandValue: deadbandValue,
+			},
+		),
+	}, subClient.monitoredItemsReqs[0].RequestedParameters)
+}
+
+func TestSubscribeClientConfigValidEventStreamingParams(t *testing.T) {
+	subscribeConfig := subscribeClientConfig{
+		InputClientConfig: input.InputClientConfig{
+			OpcUAClientConfig: opcua.OpcUAClientConfig{
+				Endpoint:       "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer",
+				SecurityPolicy: "None",
+				SecurityMode:   "None",
+				AuthMethod:     "Anonymous",
+				ConnectTimeout: config.Duration(10 * time.Second),
+				RequestTimeout: config.Duration(1 * time.Second),
+				Workarounds:    opcua.OpcUAWorkarounds{},
+			},
+			MetricName:  "testing",
+			EventGroups: make([]input.EventGroupSettings, 0),
+		},
+		SubscriptionInterval: 0,
+	}
+	subscribeConfig.EventGroups = append(subscribeConfig.EventGroups, input.EventGroupSettings{
+		SamplingInterval: 1.0,
+		EventTypeNode: input.EventNodeSettings{
+			Namespace:      "3",
+			IdentifierType: "i",
+			Identifier:     "1234",
+		},
+		Namespace:      "3",
+		IdentifierType: "i",
+		NodeIDSettings: []input.EventNodeSettings{
+			{
+				Namespace:      "3",
+				IdentifierType: "i",
+				Identifier:     "12",
+			},
+			{
+				Namespace:      "3",
+				IdentifierType: "i",
+				Identifier:     "13",
+			},
+		},
+		SourceNames: []string{"SensorXYZ"},
+		Fields:      []string{"PressureValue"},
+	})
+
+	_, err := subscribeConfig.createSubscribeClient(testutil.Logger{})
+	require.NoError(t, err)
+}
+
+func TestSubscribeClientConfigEventInputMissingSamplingInterval(t *testing.T) {
+	subscribeConfig := subscribeClientConfig{
+		InputClientConfig: input.InputClientConfig{
+			OpcUAClientConfig: opcua.OpcUAClientConfig{
+				Endpoint:       "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer",
+				SecurityPolicy: "None",
+				SecurityMode:   "None",
+				AuthMethod:     "Anonymous",
+				ConnectTimeout: config.Duration(10 * time.Second),
+				RequestTimeout: config.Duration(1 * time.Second),
+				Workarounds:    opcua.OpcUAWorkarounds{},
+			},
+			MetricName:  "testing",
+			EventGroups: make([]input.EventGroupSettings, 0),
+		},
+		SubscriptionInterval: 0,
+	}
+	subscribeConfig.EventGroups = append(subscribeConfig.EventGroups, input.EventGroupSettings{
+		EventTypeNode: input.EventNodeSettings{
+			Namespace:      "3",
+			IdentifierType: "i",
+			Identifier:     "1234",
+		},
+		Namespace:      "3",
+		IdentifierType: "i",
+		NodeIDSettings: []input.EventNodeSettings{
+			{
+				Namespace:      "3",
+				IdentifierType: "i",
+				Identifier:     "12",
+			},
+		},
+		SourceNames: []string{"SensorXYZ"},
+		Fields:      []string{"PressureValue"},
+	})
+
+	_, err := subscribeConfig.createSubscribeClient(testutil.Logger{})
+	require.NoError(t, err)
+}
+
+func TestSubscribeClientConfigEventInputMissingEventType(t *testing.T) {
+	subscribeConfig := subscribeClientConfig{
+		InputClientConfig: input.InputClientConfig{
+			OpcUAClientConfig: opcua.OpcUAClientConfig{
+				Endpoint:       "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer",
+				SecurityPolicy: "None",
+				SecurityMode:   "None",
+				AuthMethod:     "Anonymous",
+				ConnectTimeout: config.Duration(10 * time.Second),
+				RequestTimeout: config.Duration(1 * time.Second),
+				Workarounds:    opcua.OpcUAWorkarounds{},
+			},
+			MetricName:  "testing",
+			EventGroups: make([]input.EventGroupSettings, 0),
+		},
+		SubscriptionInterval: 0,
+	}
+	subscribeConfig.EventGroups = append(subscribeConfig.EventGroups, input.EventGroupSettings{
+		SamplingInterval: 1.0,
+		Namespace:        "3",
+		IdentifierType:   "i",
+		NodeIDSettings: []input.EventNodeSettings{
+			{
+				Namespace:      "3",
+				IdentifierType: "i",
+				Identifier:     "12",
+			},
+		},
+		SourceNames: []string{"SensorXYZ"},
+		Fields:      []string{"PressureValue"},
+	})
+
+	_, err := subscribeConfig.createSubscribeClient(testutil.Logger{})
+	require.ErrorContains(t, err, "invalid event_type_node_settings")
+}
+
+func TestSubscribeClientConfigEventMissingEventTypeNamespace(t *testing.T) {
+	subscribeConfig := subscribeClientConfig{
+		InputClientConfig: input.InputClientConfig{
+			OpcUAClientConfig: opcua.OpcUAClientConfig{
+				Endpoint:       "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer",
+				SecurityPolicy: "None",
+				SecurityMode:   "None",
+				AuthMethod:     "Anonymous",
+				ConnectTimeout: config.Duration(10 * time.Second),
+				RequestTimeout: config.Duration(1 * time.Second),
+				Workarounds:    opcua.OpcUAWorkarounds{},
+			},
+			MetricName:  "testing",
+			EventGroups: make([]input.EventGroupSettings, 0),
+		},
+		SubscriptionInterval: 0,
+	}
+	subscribeConfig.EventGroups = append(subscribeConfig.EventGroups, input.EventGroupSettings{
+		SamplingInterval: 1.0,
+		EventTypeNode: input.EventNodeSettings{
+			IdentifierType: "i",
+			Identifier:     "1234",
+		},
+		Namespace:      "3",
+		IdentifierType: "i",
+		NodeIDSettings: []input.EventNodeSettings{
+			{
+				Namespace:      "3",
+				IdentifierType: "i",
+				Identifier:     "12",
+			},
+		},
+		SourceNames: []string{"SensorXYZ"},
+		Fields:      []string{"PressureValue"},
+	})
+
+	_, err := subscribeConfig.createSubscribeClient(testutil.Logger{})
+	require.ErrorContains(t, err, "namespace must be set")
+}
+
+func TestSubscribeClientConfigEventMissingEventTypeIdentifierType(t *testing.T) {
+	subscribeConfig := subscribeClientConfig{
+		InputClientConfig: input.InputClientConfig{
+			OpcUAClientConfig: opcua.OpcUAClientConfig{
+				Endpoint:       "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer",
+				SecurityPolicy: "None",
+				SecurityMode:   "None",
+				AuthMethod:     "Anonymous",
+				ConnectTimeout: config.Duration(10 * time.Second),
+				RequestTimeout: config.Duration(1 * time.Second),
+				Workarounds:    opcua.OpcUAWorkarounds{},
+			},
+			MetricName:  "testing",
+			EventGroups: make([]input.EventGroupSettings, 0),
+		},
+		SubscriptionInterval: 0,
+	}
+	subscribeConfig.EventGroups = append(subscribeConfig.EventGroups, input.EventGroupSettings{
+		SamplingInterval: 1.0,
+		EventTypeNode: input.EventNodeSettings{
+			Namespace:  "3",
+			Identifier: "1234",
+		},
+		Namespace:      "3",
+		IdentifierType: "i",
+		NodeIDSettings: []input.EventNodeSettings{
+			{
+				Namespace:      "3",
+				IdentifierType: "i",
+				Identifier:     "12",
+			},
+		},
+		SourceNames: []string{"SensorXYZ"},
+		Fields:      []string{"PressureValue"},
+	})
+
+	_, err := subscribeConfig.createSubscribeClient(testutil.Logger{})
+	require.ErrorContains(t, err, "identifier_type must be set")
+}
+
+func TestSubscribeClientConfigEventMissingEventTypeIdentifier(t *testing.T) {
+	subscribeConfig := subscribeClientConfig{
+		InputClientConfig: input.InputClientConfig{
+			OpcUAClientConfig: opcua.OpcUAClientConfig{
+				Endpoint:       "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer",
+				SecurityPolicy: "None",
+				SecurityMode:   "None",
+				AuthMethod:     "Anonymous",
+				ConnectTimeout: config.Duration(10 * time.Second),
+				RequestTimeout: config.Duration(1 * time.Second),
+				Workarounds:    opcua.OpcUAWorkarounds{},
+			},
+			MetricName:  "testing",
+			EventGroups: make([]input.EventGroupSettings, 0),
+		},
+		SubscriptionInterval: 0,
+	}
+	subscribeConfig.EventGroups = append(subscribeConfig.EventGroups, input.EventGroupSettings{
+		SamplingInterval: 1.0,
+		EventTypeNode: input.EventNodeSettings{
+			Namespace:      "3",
+			IdentifierType: "i",
+		},
+		Namespace:      "3",
+		IdentifierType: "i",
+		NodeIDSettings: []input.EventNodeSettings{
+			{
+				Namespace:      "3",
+				IdentifierType: "i",
+				Identifier:     "12",
+			},
+		},
+		SourceNames: []string{"SensorXYZ"},
+		Fields:      []string{"PressureValue"},
+	})
+
+	_, err := subscribeConfig.createSubscribeClient(testutil.Logger{})
+	require.ErrorContains(t, err, "identifier must be set")
+}
+
+func TestSubscribeClientConfigEventInputMissingNodeIDs(t *testing.T) {
+	subscribeConfig := subscribeClientConfig{
+		InputClientConfig: input.InputClientConfig{
+			OpcUAClientConfig: opcua.OpcUAClientConfig{
+				Endpoint:       "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer",
+				SecurityPolicy: "None",
+				SecurityMode:   "None",
+				AuthMethod:     "Anonymous",
+				ConnectTimeout: config.Duration(10 * time.Second),
+				RequestTimeout: config.Duration(1 * time.Second),
+				Workarounds:    opcua.OpcUAWorkarounds{},
+			},
+			MetricName:  "testing",
+			EventGroups: make([]input.EventGroupSettings, 0),
+		},
+		SubscriptionInterval: 0,
+	}
+	subscribeConfig.EventGroups = append(subscribeConfig.EventGroups, input.EventGroupSettings{
+		EventTypeNode: input.EventNodeSettings{
+			Namespace:      "3",
+			IdentifierType: "i",
+			Identifier:     "1234",
+		},
+		Namespace:      "3",
+		IdentifierType: "i",
+		SourceNames:    []string{"SensorXYZ"},
+		Fields:         []string{"PressureValue"},
+	})
+
+	_, err := subscribeConfig.createSubscribeClient(testutil.Logger{})
+	require.ErrorContains(t, err, "at least one node_id must be specified")
+}
+
+func TestSubscribeClientConfigEventInputMissingFields(t *testing.T) {
+	subscribeConfig := subscribeClientConfig{
+		InputClientConfig: input.InputClientConfig{
+			OpcUAClientConfig: opcua.OpcUAClientConfig{
+				Endpoint:       "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer",
+				SecurityPolicy: "None",
+				SecurityMode:   "None",
+				AuthMethod:     "Anonymous",
+				ConnectTimeout: config.Duration(10 * time.Second),
+				RequestTimeout: config.Duration(1 * time.Second),
+				Workarounds:    opcua.OpcUAWorkarounds{},
+			},
+			MetricName:  "testing",
+			EventGroups: make([]input.EventGroupSettings, 0),
+		},
+		SubscriptionInterval: 0,
+	}
+	subscribeConfig.EventGroups = append(subscribeConfig.EventGroups, input.EventGroupSettings{
+		SamplingInterval: 1.0,
+		EventTypeNode: input.EventNodeSettings{
+			Namespace:      "3",
+			IdentifierType: "i",
+			Identifier:     "1234",
+		},
+		Namespace:      "3",
+		IdentifierType: "i",
+		NodeIDSettings: []input.EventNodeSettings{
+			{
+				Namespace:      "3",
+				IdentifierType: "i",
+				Identifier:     "12",
+			},
+		},
+		SourceNames: []string{"SensorXYZ"},
+	})
+
+	_, err := subscribeConfig.createSubscribeClient(testutil.Logger{})
+	require.ErrorContains(t, err, "at least one Field must be specified")
+}
+
+func TestSubscribeClientConfigEventInputInvalidFields(t *testing.T) {
+	subscribeConfig := subscribeClientConfig{
+		InputClientConfig: input.InputClientConfig{
+			OpcUAClientConfig: opcua.OpcUAClientConfig{
+				Endpoint:       "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer",
+				SecurityPolicy: "None",
+				SecurityMode:   "None",
+				AuthMethod:     "Anonymous",
+				ConnectTimeout: config.Duration(10 * time.Second),
+				RequestTimeout: config.Duration(1 * time.Second),
+				Workarounds:    opcua.OpcUAWorkarounds{},
+			},
+			MetricName:  "testing",
+			EventGroups: make([]input.EventGroupSettings, 0),
+		},
+		SubscriptionInterval: 0,
+	}
+	subscribeConfig.EventGroups = append(subscribeConfig.EventGroups, input.EventGroupSettings{
+		SamplingInterval: 1.0,
+		EventTypeNode: input.EventNodeSettings{
+			Namespace:      "3",
+			IdentifierType: "i",
+			Identifier:     "1234",
+		},
+		Namespace:      "3",
+		IdentifierType: "i",
+		NodeIDSettings: []input.EventNodeSettings{
+			{
+				Namespace:      "3",
+				IdentifierType: "i",
+				Identifier:     "12",
+			},
+		},
+		SourceNames: []string{"SensorXYZ"},
+		Fields:      []string{"Fieldname", ""},
+	})
+
+	_, err := subscribeConfig.createSubscribeClient(testutil.Logger{})
+	require.ErrorContains(t, err, "empty field name in fields stanza")
+}
+
+func TestSubscribeClientConfigValidEventStreamingDefaultNodeParams(t *testing.T) {
+	subscribeConfig := subscribeClientConfig{
+		InputClientConfig: input.InputClientConfig{
+			OpcUAClientConfig: opcua.OpcUAClientConfig{
+				Endpoint:       "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer",
+				SecurityPolicy: "None",
+				SecurityMode:   "None",
+				AuthMethod:     "Anonymous",
+				ConnectTimeout: config.Duration(10 * time.Second),
+				RequestTimeout: config.Duration(1 * time.Second),
+				Workarounds:    opcua.OpcUAWorkarounds{},
+			},
+			MetricName:  "testing",
+			EventGroups: make([]input.EventGroupSettings, 0),
+		},
+		SubscriptionInterval: 0,
+	}
+	subscribeConfig.EventGroups = append(subscribeConfig.EventGroups, input.EventGroupSettings{
+		SamplingInterval: 1.0,
+		EventTypeNode: input.EventNodeSettings{
+			Namespace:      "3",
+			IdentifierType: "i",
+			Identifier:     "1234",
+		},
+		Namespace:      "3",
+		IdentifierType: "i",
+		NodeIDSettings: []input.EventNodeSettings{
+			{
+				Identifier: "12",
+			},
+		},
+		SourceNames: []string{"SensorXYZ"},
+		Fields:      []string{"PressureValue"},
+	})
+
+	_, err := subscribeConfig.createSubscribeClient(testutil.Logger{})
+	require.NoError(t, err)
+
+	o := subscribeConfig.InputClientConfig.EventGroups[0].NodeIDSettings[0]
+	require.Equal(t, "i", o.IdentifierType)
+	require.Equal(t, "3", o.Namespace)
+}

plugins/inputs/opcua_listener/sample.conf

@@ -211,11 +211,36 @@
   #       deadband_value = 0.0
   #
 
+  ## Multiple event groups are allowed.
+  # [[inputs.opcua_listener.events]]
+  #   ## Polling interval for data collection
+  #   # sampling_interval = "10s"
+  #   ## Size of the notification queue
+  #   # queue_size = 10
+  #   ## Node parameter defaults for node definitions below
+  #   # namespace = ""
+  #   # identifier_type = ""
+  #   ## Specifies OPCUA Event sources to filter on
+  #   # source_names = ["SourceName1", "SourceName2"]
+  #   ## Fields to capture from event notifications
+  #   fields = ["Severity", "Message", "Time"]
+  #
+  #   ## Type or level of events to capture from the monitored nodes.
+  #   [inputs.opcua_listener.events.event_type_node]
+  #     namespace = ""
+  #     identifier_type = ""
+  #     identifier = ""
+  #
+  #   ## Nodes to monitor for event notifications associated with the defined
+  #   ## event type
+  #   [[inputs.opcua_listener.events.node_ids]]
+  #     namespace = ""
+  #     identifier_type = ""
+  #     identifier = ""
+
   ## Enable workarounds required by some devices to work correctly
   # [inputs.opcua_listener.workarounds]
-    ## Set additional valid status codes, StatusOK (0x0) is always considered valid
+  #  ## Set additional valid status codes, StatusOK (0x0) is always considered valid
-    # additional_valid_status_codes = ["0xC0"]
+  #  # additional_valid_status_codes = ["0xC0"]
-
+  #  ## Use unregistered reads instead of registered reads
-  # [inputs.opcua_listener.request_workarounds]
+  #  # use_unregistered_reads = false
-    ## Use unregistered reads instead of registered reads
-    # use_unregistered_reads = false

plugins/inputs/opcua_listener/subscribe_client.go

@@ -28,6 +28,7 @@ type subscribeClient struct {
 
 	sub                *opcua.Subscription
 	monitoredItemsReqs []*ua.MonitoredItemCreateRequest
+	eventItemsReqs     []*ua.MonitoredItemCreateRequest
 	dataNotifications  chan *opcua.PublishNotificationData
 	metrics            chan telegraf.Metric
 
@@ -91,11 +92,17 @@ func (sc *subscribeClientConfig) createSubscribeClient(log telegraf.Logger) (*su
 		return nil, err
 	}
 
+	if err := client.InitEventNodeIDs(); err != nil {
+		return nil, err
+	}
+
 	processingCtx, processingCancel := context.WithCancel(context.Background())
+
 	subClient := &subscribeClient{
 		OpcUAInputClient:   client,
 		Config:             *sc,
 		monitoredItemsReqs: make([]*ua.MonitoredItemCreateRequest, len(client.NodeIDs)),
+		eventItemsReqs:     make([]*ua.MonitoredItemCreateRequest, len(client.EventNodeMetricMapping)),
 		// 100 was chosen to make sure that the channels will not block when multiple changes come in at the same time.
 		// The channel size should be increased if reports come in on Telegraf blocking when many changes come in at
 		// the same time. It could be made dependent on the number of nodes subscribed to and the subscription interval.
@@ -115,6 +122,23 @@ func (sc *subscribeClientConfig) createSubscribeClient(log telegraf.Logger) (*su
 		subClient.monitoredItemsReqs[i] = req
 	}
 
+	log.Debugf("Creating event streaming items")
+	for i, node := range client.EventNodeMetricMapping {
+		req := opcua.NewMonitoredItemCreateRequestWithDefaults(node.NodeID, ua.AttributeIDEventNotifier, uint32(i))
+		if node.SamplingInterval != nil {
+			req.RequestedParameters.SamplingInterval = float64(time.Duration(*node.SamplingInterval) / time.Millisecond)
+		}
+		if node.QueueSize != nil {
+			req.RequestedParameters.QueueSize = *node.QueueSize
+		}
+
+		filterExtObj, err := node.CreateEventFilter()
+		if err != nil {
+			return nil, fmt.Errorf("failed to create event filter: %w", err)
+		}
+		req.RequestedParameters.Filter = filterExtObj
+		subClient.eventItemsReqs[i] = req
+	}
 	return subClient, nil
 }
 
@@ -152,7 +176,7 @@ func (o *subscribeClient) stop(ctx context.Context) <-chan struct{} {
 	return closing
 }
 
-func (o *subscribeClient) startStreamValues(ctx context.Context) (<-chan telegraf.Metric, error) {
+func (o *subscribeClient) startMonitoring(ctx context.Context) (<-chan telegraf.Metric, error) {
 	err := o.connect()
 	if err != nil {
 		switch o.Config.ConnectFailBehavior {
@@ -166,23 +190,38 @@ func (o *subscribeClient) startStreamValues(ctx context.Context) (<-chan telegra
 		return nil, err
 	}
 
-	resp, err := o.sub.Monitor(ctx, ua.TimestampsToReturnBoth, o.monitoredItemsReqs...)
+	if len(o.monitoredItemsReqs) != 0 {
-	if err != nil {
+		resp, err := o.sub.Monitor(ctx, ua.TimestampsToReturnBoth, o.monitoredItemsReqs...)
-		return nil, fmt.Errorf("failed to start monitoring items: %w", err)
+		if err != nil {
-	}
+			return nil, fmt.Errorf("failed to start monitoring items: %w", err)
-	o.Log.Debug("Monitoring items")
+		}
+		o.Log.Debug("Monitoring items")
 
-	for idx, res := range resp.Results {
+		for idx, res := range resp.Results {
-		if !o.StatusCodeOK(res.StatusCode) {
+			if !o.StatusCodeOK(res.StatusCode) {
-			// Verify NodeIDs array has been built before trying to get item; otherwise show '?' for node id
+				// Verify NodeIDs array has been built before trying to get item; otherwise show '?' for node id
-			if len(o.OpcUAInputClient.NodeIDs) > idx {
+				if len(o.OpcUAInputClient.NodeIDs) > idx {
-				o.Log.Debugf("Failed to create monitored item for node %v (%v)",
+					o.Log.Debugf("Failed to create monitored item for node %v (%v)",
-					o.OpcUAInputClient.NodeMetricMapping[idx].Tag.FieldName, o.OpcUAInputClient.NodeIDs[idx].String())
+						o.OpcUAInputClient.NodeMetricMapping[idx].Tag.FieldName, o.OpcUAInputClient.NodeIDs[idx].String())
-			} else {
+				} else {
-				o.Log.Debugf("Failed to create monitored item for node %v (%v)", o.OpcUAInputClient.NodeMetricMapping[idx].Tag.FieldName, '?')
+					o.Log.Debugf("Failed to create monitored item for node %v (%v)", o.OpcUAInputClient.NodeMetricMapping[idx].Tag.FieldName, '?')
+				}
+				return nil, fmt.Errorf("creating monitored item failed with status code: %w", res.StatusCode)
 			}
+		}
+	}
 
-			return nil, fmt.Errorf("creating monitored item failed with status code: %w", res.StatusCode)
+	if len(o.eventItemsReqs) != 0 {
+		resp, err := o.sub.Monitor(ctx, ua.TimestampsToReturnBoth, o.eventItemsReqs...)
+		if err != nil {
+			return nil, fmt.Errorf("failed to start monitoring event stream: %w", err)
+		}
+		o.Log.Debug("Monitoring events")
+
+		for _, res := range resp.Results {
+			if !o.StatusCodeOK(res.StatusCode) {
+				return nil, fmt.Errorf("creating monitored event streaming item failed with status code: %w", res.StatusCode)
+			}
 		}
 	}
 
@@ -207,6 +246,10 @@ func (o *subscribeClient) processReceivedNotifications() {
 				o.Log.Error(res.Error)
 				continue
 			}
+			if res.Value == nil {
+				o.Log.Error("Received nil notification")
+				return
+			}
 
 			switch notif := res.Value.(type) {
 			case *ua.DataChangeNotification:
@@ -220,7 +263,13 @@ func (o *subscribeClient) processReceivedNotifications() {
 						o.NodeIDs[i].String(), oldValue, o.LastReceivedData[i].Value)
 					o.metrics <- o.MetricForNode(i)
 				}
-
+			case *ua.EventNotificationList:
+				o.Log.Debugf("Processing event notification with %d events", len(notif.Events))
+				// It is assumed the events are ordered chronologically
+				for _, event := range notif.Events {
+					i := int(event.ClientHandle)
+					o.metrics <- o.MetricForEvent(i, event)
+				}
 			default:
 				o.Log.Warnf("Received notification has unexpected type %s", reflect.TypeOf(res.Value))
 			}