fix(nats-jetstream): correctly count messages that should be redelive…

…red (waiting for ack) towards keda value (kedacore#3809)

* fix: keda now include the messages that should be retried in the count of pending messages used for scaling

Signed-off-by: Antoine Laffargue <antoine.laffargue@gmail.com>

* chore: update changelog

Signed-off-by: Antoine Laffargue <antoine.laffargue@gmail.com>

Signed-off-by: Antoine Laffargue <antoine.laffargue@gmail.com>
Signed-off-by: Pedro Tanaka <pedro.stanaka@gmail.com>

CHANGELOG.md

@@ -44,6 +44,7 @@ To learn more about our roadmap, we recommend reading [this document](ROADMAP.md
 - **General:** Respect optional parameter inside envs for ScaledJobs ([#3568](https://github.com/kedacore/keda/issues/3568))
 - **Azure Blob Scaler** Store forgotten logger ([#3811](https://github.com/kedacore/keda/issues/3811))
 - **Prometheus Scaler:** Treat Inf the same as Null result ([#3644](https://github.com/kedacore/keda/issues/3644))
+- **NATS Jetstream:** Correctly count messages that should be redelivered (waiting for ack) towards keda value ([#3787](https://github.com/kedacore/keda/issues/3787))
 
 ### Deprecations
 

pkg/scalers/nats_jetstream_scaler.go

@@ -195,7 +195,7 @@ func (s *natsJetStreamScaler) getMaxMsgLag() int64 {
 
 	for _, consumer := range s.stream.Consumers {
 		if consumer.Name == consumerName {
-			return int64(consumer.NumPending)
+			return int64(consumer.NumPending + consumer.NumAckPending)
 		}
 	}
 	return s.stream.State.LastSequence