Nak with delay only working once and not on redelivery.

[marumarumaru89]

Hello,

I am trying to implement a wait strategy using the .nak() method with a delay, such as:

except Exception as e:
print(e)
if delivery_attempt == 6:
await nc.publish_to_dlq_preprocess(msg_data, correlation_id)
await msg.term()
preprocessor_fail.inc()
logger.log(
f"Fifth message processing failed, terminated message and published to dlq. Error: {e}",
correlation_id,
)
continue
else:
await msg.nak(delay=5)
logger.log(
f"Error during preprocess, nak with 5s delay. Error: {e}",
correlation_id,
attempt=delivery_attempt,
)
continue

Inside a while = True loop that continuously waits for and fetches messages.
This works once, giving me this print:

{"app_id": "test", "correlation_id": "", "message": "Error during preprocess, nak with 5s delay. Error: Expecting ',' delimiter: line 1
column 23 (char 22)", "attempt": 1}
Waiting for message...
Expecting ',' delimiter: line 1 column 23 (char 22)
{"app_id": "test", "correlation_id": "", "message": "Error during preprocess, nak with 5s delay. Error: Expecting ',' delimiter: line 1 column 23 (char 22)", "attempt": 2}
Waiting for message...

After that, no further redelivery attempts are made. With a con report it shows Ack Pending: 1, Redelivered: 1.

I first tried to implement this using the Backoff parameter of the consumer, but when NAKing a message, it was redelivered immediately, and when doing neither NAK nor ACK it was not redelivered at all, despite Ack Wait being on 1m and the first backoff step being 1m as well.

Would appreciate any help!