After a message is modified in the queue, how to send the modified message to the dead letter queue instead of the original message after calling the channel.basicNac() method

[cutepikachu-cn]

After a message is modified in the queue, how to send the modified message to the dead letter queue instead of the original message after calling the channel.basicNac() method ?

I hope to get the error information in the message in the handleDeadLetter method

@Slf4j
@Component
public class SmsConsumer implements IConsumer<SmsModel, SmsMessage> {

    @RabbitListener(queues = SmsMQConfiguration.QUEUE, ackMode = "AUTO")
    @Override
    public void handle(SmsMessage message, Channel channel, @Header(AmqpHeaders.DELIVERY_TAG) long tag) {
        try {
            // ...
        } catch (Exception e) {
            // modify message
            message.setException(e);
            log.error("Message {} processing failed, sending to dead letter queue: {}", message.hashCode(), e.getMessage());
            try {
                channel.basicNack(tag, false, false);
            } catch (Exception ex) {
                if (log.isErrorEnabled()) {
                    log.error("Failed to nack the message: {}", ex.getMessage());
                }
            }
        }
    }

    @RabbitListener(queues = SmsMQConfiguration.DEAD_QUEUE, ackMode = "AUTO")
    @Override
    public void handleDeadLetter(SmsMessage message) {
        SmsModel smsModel = message.getMessage();
        // ...
        Exception e = message.getException();
        // e is null
        log.error("Handling dead letter message - {}, exception: ", message.hashCode(), e);
    }

}

[artembilan]

Messages in RabbitMQ store are immutable. So, there is no way to modify whatever is already there.
That's why we provide an alternative to the mentioned basicNack as manual producing to DLQ: https://docs.spring.io/spring-amqp/reference/amqp/resilience-recovering-from-errors-and-broker-failures.html#async-listeners.

See RepublishMessageRecoverer for more details.