FULL OC-DISCOVERY LOGIC

daemons/node/pubsub/subscribe.go

@@ -0,0 +1,102 @@
+package pubsub
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"oc-discovery/daemons/node/common"
+	"slices"
+	"time"
+
+	oclib "cloud.o-forge.io/core/oc-lib"
+	"cloud.o-forge.io/core/oc-lib/models/peer"
+	"cloud.o-forge.io/core/oc-lib/tools"
+	pubsub "github.com/libp2p/go-libp2p-pubsub"
+)
+
+func (ps *PubSubService) initSubscribeEvents(ctx context.Context) error {
+	if err := ps.subscribeEvents(ctx, nil, tools.PB_SEARCH, "", -1); err != nil {
+		return err
+	}
+	return nil
+}
+
+// generic function to subscribe to DHT flow of event
+func (ps *PubSubService) subscribeEvents(
+	ctx context.Context, dt *tools.DataType, action tools.PubSubAction, peerID string, timeout int,
+) error {
+	// define a name app.action#peerID
+	name := action.String() + "#" + peerID
+	if dt != nil { // if a datatype is precised then : app.action.datatype#peerID
+		name = action.String() + "." + (*dt).String() + "#" + peerID
+	}
+	topic, err := ps.PS.Join(name) // find out the topic
+	if err != nil {
+		return err
+	}
+
+	sub, err := topic.Subscribe() // then subscribe to it
+	if err != nil {
+		return err
+	}
+	ps.mutex.Lock() // add safely in cache your subscription.
+	ps.Subscription = append(ps.Subscription, name)
+	ps.mutex.Unlock()
+
+	// launch loop waiting for results.
+	go ps.waitResults(ctx, sub, name, timeout)
+
+	return nil
+}
+
+func (ps *PubSubService) waitResults(ctx context.Context, sub *pubsub.Subscription, topicName string, timeout int) {
+	logger := oclib.GetLogger()
+	defer ctx.Done()
+	for {
+		ps.mutex.Lock()                                   // check safely if cache is actually notified subscribed to topic
+		if !slices.Contains(ps.Subscription, topicName) { // if not kill the loop.
+			break
+		}
+		ps.mutex.Unlock()
+		// if still subscribed -> wait for new message
+		var cancel context.CancelFunc
+		if timeout != -1 {
+			ctx, cancel = context.WithTimeout(ctx, time.Duration(timeout)*time.Second)
+			defer cancel()
+		}
+		msg, err := sub.Next(ctx)
+		if err != nil {
+			if errors.Is(err, context.DeadlineExceeded) {
+				// timeout hit, no message before deadline kill subsciption.
+				ps.mutex.Lock()
+				subs := []string{}
+				for _, ss := range ps.Subscription {
+					if ss != topicName {
+						subs = append(subs, ss)
+					}
+				}
+				ps.Subscription = subs
+				ps.mutex.Unlock()
+				return
+			}
+			continue
+		}
+		var evt common.Event
+		if err := json.Unmarshal(msg.Data, &evt); err != nil { // map to event
+			continue
+		}
+		if p, err := ps.Node.GetPeerRecord(ctx, evt.From); err == nil {
+			if err := ps.processEvent(ctx, p, &evt, topicName); err != nil {
+				logger.Err(err)
+			}
+		}
+	}
+}
+
+func (ps *PubSubService) processEvent(
+	ctx context.Context, p *peer.Peer, event *common.Event, topicName string) error {
+	if err := event.Verify(p); err != nil {
+		return err
+	}
+	return ps.handleEvent(ctx, topicName, event)
+}