我可以使用spring.cloud.stream.bindings吗？ <channel> .group何时使用RabbitMQ获得一次准确的交货？

Question

so I was reading this tutorial to configure RabbitMQ and SpringBoot.

At a certain point it is said:

Most of the time, we need the message to be processed only once. Spring Cloud Stream implements this behavior via consumer groups.

So I started looking for more information on Spring docs it is written that:

When doing so, different instances of an application are placed in a competing consumer relationship, where only one of the instances is expected to handle a given message.

Spring Cloud Stream models this behavior through the concept of a consumer group. (Spring Cloud Stream consumer groups are similar to and inspired by Kafka consumer groups.)

So I setup here two nodes with Spring Boot Cloud Stream and RabbitMQ and using spring.cloud.stream.bindings.<channel>.group .

This to me still looks like at-least-once behavior. Am I wrong in assuming that? Should I still manage the possibility to process a message twice even using spring.cloud.stream.bindings.<channel>.group ?

Thank you

Answer 1

It's at least once. The connection might close before the ack is sent. Rare, but possible.