What should I do if publishing confirm failed with the 'deliveryTag'

[Icarus9913]

Sorry for asking this simple question. If I publish one msg and get the confirmations (confirmations.ack==false). In this situation, how can I re-publish this msg? Should I use channel.Nack()? And how can I imitate the return confirmation ack is false?

  func main() {
	conn, err := amqp.Dial("amqp://guest:guest@localhost:5672/")
	if nil != err {
		panic(err)
	}

	ch, err := conn.Channel()
	if nil != err {
		panic(err)
	}

	queue, err := ch.QueueDeclare("hey", true, false, false, false, nil)
	if nil != err {
		panic(err)
	}

	if err = ch.Confirm(false); nil != err {
		panic(err)
	}

	confirms := ch.NotifyPublish(make(chan amqp.Confirmation, 1))

	body := "hello"
	err = ch.Publish("", queue.Name, false, false,
		amqp.Publishing{
			ContentType: "text/plain",
			Body:        []byte(body),
		},
	)
	if nil != err {
		panic("sending failed: " + err.Error())
	}

	if confirmed := <-confirms; confirmed.Ack {
		fmt.Println("good")
	} else {
		fmt.Println("what should I do?")
		tag := confirmed.DeliveryTag
		ch.Nack(tag, false, true) //Is that right to use this method? But I can't imitate this situation. I want it to re-publish
	}
  }

[Icarus9913]

I mean that I can not locate the exact msg by the confirmed.DeliveryTag. I wanna try to re-publish this msg if the confirmed.Ack is false.

[ArtyomGabeev]

@Icarus9913 you need to preserve an inflight messages by our own, example using map[uint64]amqp.Publishing.

[samyonr]

As mentions above, you need to store your messages coupled with the delivery number. Once confirmed, remove it from the map, if it's not confirmed, re-publish it again (probably up to certain amount of attempts). You can manually calculate the delivery number, or use the mechanism in #478 that was merged but not released. However, the exact same commit was released in rabbitmq/amqp091-go: https://github.com/rabbitmq/amqp091-go/releases/tag/v1.2.0