How to return message to the end of queue in rabbitmq?

[lzyrapx]

Hi, all. I'd like to ask how to return message to the end of queue in rabbitmq?

Example:

• Message1 gets consumed and creates some record in database.
• Message2 gets consumed and checks if there is record in database, and if yes, then it updates the record. If there is no record in database, message should be returned to the end of queue.

The Code below did not work.

    for delivery := range msg {
               exist := check()
        if exist != nil { //yes
                        update()
            err := delivery.Ack(false)
            logger.Info("Ack error : ", err)
        } else { // no
            // err := delivery.Reject(true)
            err := delivery.Nack(false, true)
            logger.Info("Reject error : ", err)
        }
   }

Thanks in advance.

[shekhar-kamble]

When requeue is true, request the server to deliver this message to a different consumer. If it is not possible or requeue is false, the message will be dropped or delivered to a server configured dead-letter queue.

refer to https://godoc.org/github.com/streadway/amqp#Delivery.Nack

[houseofcat]

@LzyRapx A popular strategy is to pull out the message from a Channel with Confirm enabled, so you can perform Acks/Nacks like you have sample code for. Then you try to perform some operation against the message - handle when things did not go as planned by publishing the message to an alternative queue. Once successfully published to other queue, acknowledge message from the original channel. In your case, you would publish to the source Queue (instead of another destination) and it would naturally be at the bottom for replay later.

[lariknep]

The way to requeue the message to the beginning of the source queue (republish) is create a queue dead-letter-exchange policy without Exchange Name specification. In this case a rejected message will be republished back to the original Exchange with the original Routing Key. This kind of policy should be established through the broker HTTP API.