[pubsub/jetstream] Add missing concurrencyMode support for queue-based handler (dapr#3232)

Signed-off-by: Byron Ruth <[email protected]>
Co-authored-by: Alessandro (Ale) Segala <[email protected]>

Author: bruth

pubsub/jetstream/jetstream.go

@@ -237,6 +237,21 @@ func (js *jetstreamPubSub) Subscribe(ctx context.Context, req pubsub.SubscribeRe
 		}
 	}
 
+	// Choose the correct handler based on the concurrency model.
+	var concHandler nats.MsgHandler
+	switch js.meta.Concurrency {
+	case pubsub.Single:
+		concHandler = natsHandler
+	case pubsub.Parallel:
+		concHandler = func(msg *nats.Msg) {
+			js.wg.Add(1)
+			go func() {
+				natsHandler(msg)
+				js.wg.Done()
+			}()
+		}
+	}
+
 	var err error
 	streamName := js.meta.StreamName
 	if streamName == "" {
@@ -245,35 +260,19 @@ func (js *jetstreamPubSub) Subscribe(ctx context.Context, req pubsub.SubscribeRe
 			return err
 		}
 	}
-	var subscription *nats.Subscription
+	var sub *nats.Subscription
 
 	consumerInfo, err := js.jsc.AddConsumer(streamName, &consumerConfig)
 	if err != nil {
 		return err
 	}
 
 	if queue := js.meta.QueueGroupName; queue != "" {
-		js.l.Debugf("nats: subscribed to subject %s with queue group %s",
-			req.Topic, js.meta.QueueGroupName)
-		subscription, err = js.jsc.QueueSubscribe(req.Topic, queue, natsHandler, nats.Bind(streamName, consumerInfo.Name))
+		js.l.Debugf("nats: subscribed to subject %s with queue group %s", req.Topic, js.meta.QueueGroupName)
+		sub, err = js.jsc.QueueSubscribe(req.Topic, queue, concHandler, nats.Bind(streamName, consumerInfo.Name))
 	} else {
 		js.l.Debugf("nats: subscribed to subject %s", req.Topic)
-		subscription, err = js.jsc.Subscribe(
-			req.Topic,
-			func(msg *nats.Msg) {
-				switch js.meta.Concurrency {
-				case pubsub.Single:
-					natsHandler(msg)
-				case pubsub.Parallel:
-					js.wg.Add(1)
-					go func() {
-						natsHandler(msg)
-						js.wg.Done()
-					}()
-				}
-			},
-			nats.Bind(streamName, consumerInfo.Name),
-		)
+		sub, err = js.jsc.Subscribe(req.Topic, concHandler, nats.Bind(streamName, consumerInfo.Name))
 	}
 	if err != nil {
 		return err
@@ -286,7 +285,7 @@ func (js *jetstreamPubSub) Subscribe(ctx context.Context, req pubsub.SubscribeRe
 		case <-ctx.Done():
 		case <-js.closeCh:
 		}
-		err := subscription.Unsubscribe()
+		err := sub.Unsubscribe()
 		if err != nil {
 			js.l.Warnf("nats: error while unsubscribing from topic %s: %v", req.Topic, err)
 		}