Add SetTriggering functionality and example

examples/trigger/trigger.go

@@ -0,0 +1,175 @@
+// Copyright 2018-2020 opcua authors. All rights reserved.
+// Use of this source code is governed by a MIT-style license that can be
+// found in the LICENSE file.
+
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/gopcua/opcua"
+	"github.com/gopcua/opcua/debug"
+	"github.com/gopcua/opcua/id"
+	"github.com/gopcua/opcua/ua"
+)
+
+func main() {
+	var (
+		endpoint      = flag.String("endpoint", "opc.tcp://morchard-mbp1.local:53530/OPCUA/SimulationServer", "OPC UA Endpoint URL")
+		policy        = flag.String("policy", "", "Security policy: None, Basic128Rsa15, Basic256, Basic256Sha256. Default: auto")
+		mode          = flag.String("mode", "", "Security mode: None, Sign, SignAndEncrypt. Default: auto")
+		certFile      = flag.String("cert", "", "Path to cert.pem. Required for security mode/policy != None")
+		keyFile       = flag.String("key", "", "Path to private key.pem. Required for security mode/policy != None")
+		triggerNodeID = flag.String("trigger", "", "node id to trigger with")
+		reportNodeID  = flag.String("report", "", "node id value to report on trigger")
+		filter        = flag.String("filter", "timestamp", "DataFilter: status, value, timestamp.")
+		interval      = flag.String("interval", opcua.DefaultSubscriptionInterval.String(), "subscription interval")
+	)
+	flag.BoolVar(&debug.Enable, "debug", false, "enable debug logging")
+	flag.Parse()
+	log.SetFlags(0)
+
+	subInterval, err := time.ParseDuration(*interval)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// add an arbitrary timeout to demonstrate how to stop a subscription
+	// with a context.
+	d := 60 * time.Second
+	ctx, cancel := context.WithTimeout(context.Background(), d)
+	defer cancel()
+
+	endpoints, err := opcua.GetEndpoints(*endpoint)
+	if err != nil {
+		log.Fatal(err)
+	}
+	ep := opcua.SelectEndpoint(endpoints, *policy, ua.MessageSecurityModeFromString(*mode))
+	if ep == nil {
+		log.Fatal("Failed to find suitable endpoint")
+	}
+
+	fmt.Println("*", ep.SecurityPolicyURI, ep.SecurityMode)
+
+	opts := []opcua.Option{
+		opcua.SecurityPolicy(*policy),
+		opcua.SecurityModeString(*mode),
+		opcua.CertificateFile(*certFile),
+		opcua.PrivateKeyFile(*keyFile),
+		opcua.AuthAnonymous(),
+		opcua.SecurityFromEndpoint(ep, ua.UserTokenTypeAnonymous),
+	}
+
+	c := opcua.NewClient(ep.EndpointURL, opts...)
+	if err := c.Connect(ctx); err != nil {
+		log.Fatal(err)
+	}
+	defer c.Close()
+
+	notifyCh := make(chan *opcua.PublishNotificationData)
+
+	sub, err := c.Subscribe(&opcua.SubscriptionParameters{
+		Interval: subInterval,
+	}, notifyCh)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer sub.Cancel()
+	log.Printf("Created subscription with id %v", sub.SubscriptionID)
+
+	triggeringNode, err := ua.ParseNodeID(*triggerNodeID)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	triggeredNode, err := ua.ParseNodeID(*reportNodeID)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	miCreateRequests := []*ua.MonitoredItemCreateRequest{
+		opcua.NewMonitoredItemCreateRequestWithDefaults(triggeringNode, ua.AttributeIDValue, 42),
+		{
+			ItemToMonitor: &ua.ReadValueID{
+				NodeID:       triggeredNode,
+				AttributeID:  ua.AttributeIDValue,
+				DataEncoding: &ua.QualifiedName{},
+			},
+			MonitoringMode: ua.MonitoringModeSampling,
+			RequestedParameters: &ua.MonitoringParameters{
+				ClientHandle:     43,
+				DiscardOldest:    true,
+				Filter:           getFilter(*filter),
+				QueueSize:        10,
+				SamplingInterval: 0.0,
+			},
+		},
+	}
+
+	subRes, err := sub.Monitor(ua.TimestampsToReturnBoth, miCreateRequests...)
+	if err != nil || subRes.Results[0].StatusCode != ua.StatusOK {
+		log.Fatal(err)
+	}
+
+	go sub.Run(ctx) // start Publish loop
+
+	triggeringServerID, triggeredServerID := subRes.Results[0].MonitoredItemID, subRes.Results[1].MonitoredItemID
+	tRes, err := sub.SetTriggering(triggeringServerID, []uint32{triggeredServerID}, []uint32{})
+
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	log.Print(tRes)
+
+	// read from subscription's notification channel until ctx is cancelled
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case res := <-notifyCh:
+			if res.Error != nil {
+				log.Print(res.Error)
+				continue
+			}
+
+			switch x := res.Value.(type) {
+			case *ua.DataChangeNotification:
+				for _, item := range x.MonitoredItems {
+					data := item.Value.Value.Value()
+					log.Printf("MonitoredItem with client handle %v = %v", item.ClientHandle, data)
+				}
+
+			default:
+				log.Printf("what's this publish result? %T", res.Value)
+			}
+		}
+	}
+}
+
+func getFilter(filterStr string) *ua.ExtensionObject {
+
+	var filter ua.DataChangeFilter
+	switch filterStr {
+	case "status":
+		filter = ua.DataChangeFilter{Trigger: ua.DataChangeTriggerStatus}
+	case "value":
+		filter = ua.DataChangeFilter{Trigger: ua.DataChangeTriggerStatusValue}
+	case "timestamp":
+		filter = ua.DataChangeFilter{Trigger: ua.DataChangeTriggerStatusValueTimestamp}
+	default:
+		log.Fatalf("Unable to match to a valid filter type: %v\nShould be status, value, or timestamp", filterStr)
+	}
+
+	return &ua.ExtensionObject{
+		EncodingMask: ua.ExtensionObjectBinary,
+		TypeID: &ua.ExpandedNodeID{
+			NodeID: ua.NewNumericNodeID(0, id.DataChangeFilter_Encoding_DefaultBinary),
+		},
+		Value: filter,
+	}
+}

subscription.go

@@ -112,6 +112,22 @@ func (s *Subscription) Unmonitor(monitoredItemIDs ...uint32) (*ua.DeleteMonitore
 	return res, err
 }
 
+func (s *Subscription) SetTriggering(triggeringItemId uint32, add, remove []uint32) (*ua.SetTriggeringResponse, error) {
+	// Part 4, 5.12.5.2 SetTriggering Service Parameters
+	req := &ua.SetTriggeringRequest{
+		SubscriptionID:   s.SubscriptionID,
+		TriggeringItemID: triggeringItemId,
+		LinksToAdd:       add,
+		LinksToRemove:    remove,
+	}
+
+	var res *ua.SetTriggeringResponse
+	err := s.c.Send(req, func(v interface{}) error {
+		return safeAssign(v, &res)
+	})
+	return res, err
+}
+
 func (s *Subscription) publish(acks []*ua.SubscriptionAcknowledgement) (*ua.PublishResponse, error) {
 	if acks == nil {
 		acks = []*ua.SubscriptionAcknowledgement{}