Why is the confirm callback called before I invoked Channel.ack - spring-amqp

Question

I'm currently trying to understand why my ConfirmCallback is called before I invoked Channel.basicAck / Channel.basicNack on the ChannelAwareMessageListener.
Please find below my current setup
#Component
public class MyMessageListener implements ChannelAwareMessageListener {
private Logger LOGGER = LoggerFactory.getLogger(MyMessageListener.class);
#Override
public void onMessage(Message message, Channel channel) throws Exception {
Thread.sleep(1000L);
String arg = String.valueOf(message.getBody());
LOGGER.info("Received message {}", arg);
Thread.sleep(1000L);
channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
}
}
#Component
public class LoggingConfirmCallback implements RabbitTemplate.ConfirmCallback{
private Logger LOGGER = LoggerFactory.getLogger(LoggingConfirmCallback.class);
#Override
public void confirm(CorrelationData correlationData, boolean ack, String cause) {
LOGGER.info("Received confirm with result {}", ack);
}
}
#SpringBootApplication
#Configuration
public class Application {
#Autowired
RabbitTemplate rabbitTemplate;
public static void main(String[] args) {
ConfigurableApplicationContext context = SpringApplication.run(Application.class, args);
context.getBean(Application.class).doIt();
}
public void doIt() {
rabbitTemplate.convertAndSend(null, null, "hello", new CorrelationData(UUID.randomUUID().toString()));
}
#Bean
#Qualifier("confirmConnectionFactory")
ConnectionFactory confirmConnectionFactory() {
CachingConnectionFactory factory = new CachingConnectionFactory();
factory.setPublisherConfirms(true);
factory.setHost("192.168.59.103");
factory.setChannelCacheSize(5);
return factory;
}
#Bean
#Primary
RabbitTemplate firstExchange(#Qualifier("confirmConnectionFactory") ConnectionFactory connectionFactory, LoggingConfirmCallback loggingConfirmCallback) {
RabbitTemplate rabbitTemplate = new RabbitTemplate(connectionFactory);
rabbitTemplate.setConfirmCallback(loggingConfirmCallback);
rabbitTemplate.setExchange("first");
rabbitTemplate.setMandatory(true);
return rabbitTemplate;
}
#Bean
MessageListenerAdapter myMessageListenerAdapter(MyMessageListener receiver) {
return new MessageListenerAdapter(receiver);
}
#Bean
SimpleMessageListenerContainer myQueueListener(#Qualifier("confirmConnectionFactory")ConnectionFactory connectionFactory, MessageListenerAdapter listenerAdapter) {
SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
container.setConnectionFactory(connectionFactory);
container.setAcknowledgeMode(AcknowledgeMode.MANUAL);
container.setQueueNames("first.queue");
container.setMessageListener(listenerAdapter);
return container;
}
What I see in the logging is this
2015-07-17 08:56:32.352 INFO 5892 --- [ main] com.coderskitchen.rmqdct.Application : Started Application in 1.393 seconds (JVM running for 1.704)
2015-07-17 08:56:32.372 INFO 5892 --- [168.59.103:5672] c.c.rmqdct.LoggingConfirmCallback : Received confirm with result true
2015-07-17 08:56:33.373 INFO 5892 --- [cTaskExecutor-1] c.c.rmqdct.MyMessageListener : Received message [B#67962299
But I expected to the the message
Received confirm with result true
after
Received message [B#67962299
Thanks in advance
Peter

Answer 1

Publisher confirms have nothing to do with message reception.
The broker confirms that it has taken responsibility for the message by successfully delivering it to the configured queue(s).
It is quite independent of the consumer acknowledging reception. If you need that, you will have to send an application-level message back to the producer.