fix: fix golint errors

internal/natsclient/jetstream.go

@@ -82,7 +82,7 @@ func (j *Jetstream) StartJetstreamMessaging() {
 // Subscribe subscribes to a list of subjects and returns a channel with incoming messages
 func (j *Jetstream) createSubscribe(subject string) chan *Message {
 
-	messageHandler, h := messageHandlerFactoryJetstream()
+	messageHandler, h := j.messageHandlerFactoryJetstream()
 	_, err := j.jetstream.Subscribe(
 		subject,
 		messageHandler,
@@ -104,7 +104,12 @@ func (j *Jetstream) createSubscribe(subject string) chan *Message {
 func (j *Jetstream) jetstreamSubscribe(h chan *Message) {
 	for msg := range h {
 		var publishTime time.Time
-		publishTime.UnmarshalBinary(msg.Data)
+		err := publishTime.UnmarshalBinary(msg.Data)
+		if err != nil {
+			j.logger.Error("unable to unmarshal binary data for publishTime.")
+			j.logger.Info("received message but could not calculate latency due to unmarshalling error.", zap.String("subject", msg.Subject))
+			return
+		}
 		latency := time.Since(publishTime).Seconds()
 		j.metrics.Latency.Observe(latency)
 		j.metrics.SuccessCounter.WithLabelValues("successful subscribe").Add(1)
@@ -137,23 +142,16 @@ func (j *Jetstream) jetstreamPublish(subject string) {
 	}
 }
 
-// Close closes NATS connection
-func (j *Jetstream) close() {
-	if err := j.connection.FlushTimeout(j.config.FlushTimeout); err != nil {
-		j.logger.Error("could not flush", zap.Error(err))
-	}
-
-	j.connection.Close()
-	j.logger.Info("NATS is closed.")
-}
-
-func messageHandlerFactoryJetstream() (nats.MsgHandler, chan *Message) {
+func (j *Jetstream) messageHandlerFactoryJetstream() (nats.MsgHandler, chan *Message) {
 	ch := make(chan *Message)
 	return func(msg *nats.Msg) {
 		ch <- &Message{
 			Subject: msg.Subject,
 			Data:    msg.Data,
 		}
-		msg.Ack()
+		err := msg.Ack()
+		if err != nil {
+			j.logger.Error("Failed to acknowledge the message", zap.Error(err))
+		}
 	}, ch
 }