outbox for gateways

api/pkg/messaging/internal/producer/producer.go

@@ -17,6 +17,7 @@ func (p *ChannelProducer) SendMessage(envelope me.Envelope) error {
 	// TODO: won't work with Kafka, need to serialize/deserialize
 	if err := p.broker.Publish(envelope); err != nil {
 		p.logger.Warn("Failed to publish message", zap.Error(err), mzap.Envelope(envelope))
+		return err
 	}
 	return nil
 }