BackOffPolicy and SimpleRetryPolicy not in effect when injected into RetryTemplate

Question

I am using Spring AMQP to send messages and be able to perform retries on a "custom" Exception. Lets say I have a Receiver which throws a custom exception "EventException" and for that, I want there to be a n number of retries (in our example 5). Between the retries I also want there to be a 5 seconds delay as well. Here is my source code:

@SpringBootApplication
public class DemoApplication implements CommandLineRunner {

    final static String queueName = "testing-queue";

    @Autowired
    AnnotationConfigApplicationContext context;

    @Autowired
    RabbitTemplate rabbitTemplate;

    @Bean
    Queue queue() {
        Map<String, Object> arguments = new HashMap<String, Object>();
        arguments.put("x-dead-letter-exchange", "dead-letter-exchange");
        Queue queue = new Queue(queueName, true, false, false, arguments);
        return queue;
    }

    @Bean
    TopicExchange exchange() {
        return new TopicExchange("testing-exchange");
    }

    @Bean
    Binding binding(Queue queue, TopicExchange exchange) {
        return BindingBuilder.bind(queue).to(exchange).with(queueName);
    }

    @Bean
    Queue deadLetterQueue() {
        return new Queue("dead-letter-queue", true);
    }

    @Bean
    FanoutExchange deadLetterExchange() {
        return new FanoutExchange("dead-letter-exchange");
    }

    @Bean
    Binding deadLetterBinding(Queue deadLetterQueue, FanoutExchange deadLetterExchange) {
        return BindingBuilder.bind(deadLetterQueue).to(deadLetterExchange);
    }

    @Bean
    ConnectionFactory connectionFactory() {
        CachingConnectionFactory connectionFactory = 
                new CachingConnectionFactory("localhost");

        connectionFactory.setUsername("guest");
        connectionFactory.setPassword("guest");

        return connectionFactory;
    }

    @Bean
    SimpleMessageListenerContainer container(
            ConnectionFactory connectionFactory,
            MessageListenerAdapter listenerAdapter,
            RetryOperationsInterceptor interceptor) {

        Advice[] adviceChain = { interceptor };

        SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
        container.setConnectionFactory(connectionFactory);
        container.setQueueNames(queueName);
        container.setAdviceChain(adviceChain);
        container.setMessageListener(listenerAdapter);

        return container;
    }

    @Bean
    Receiver receiver() {
        return new Receiver();
    }

    @Bean
    MessageListenerAdapter listenerAdapter(Receiver receiver) {
        MessageListenerAdapter adapter = 
                new MessageListenerAdapter(receiver, "receiveMessage");

        return adapter;
    }

    @Bean
    RetryOperations retryTemplate() {
         Map<Class<? extends Throwable>, Boolean> retryableExceptions = 
                 new HashMap<Class<? extends Throwable>, Boolean>();
        retryableExceptions.put(EventException.class, false);

        FixedBackOffPolicy backoffPolicy = new FixedBackOffPolicy();
        backoffPolicy.setBackOffPeriod(5000);

        RetryTemplate retryTemplate = new RetryTemplate();
        retryTemplate.setBackOffPolicy(backoffPolicy);
        retryTemplate.setRetryPolicy(new SimpleRetryPolicy(5, retryableExceptions));

        return retryTemplate;
    }

    @Bean
    RetryOperationsInterceptor interceptor(RetryOperations retryTemplate) {
        RetryOperationsInterceptor interceptor = new RetryOperationsInterceptor();
        interceptor.setRecoverer(new CustomMessageRecover());
        interceptor.setRetryOperations(retryTemplate);

        return interceptor;
//      return RetryInterceptorBuilder
//              .stateless()
//              //.retryOperations(retryTemplate)
//              .maxAttempts(5)
//              .recoverer(new CustomMessageRecover()).build();
    }

    public static void main(String[] args) throws InterruptedException {
        SpringApplication.run(DemoApplication.class, args);
    }

    @Override
    public void run(String... args) throws Exception {
        System.out.println("Sending message...");
        rabbitTemplate.convertAndSend(queueName, "Hello from RabbitMQ!");
        context.close();
    }

    public class Receiver {

        public void receiveMessage(String message) throws Exception {
            System.out.println("!!!!!!!!Message has been recieved!!!!!!");
            throw new EventException("TESTING");
        }
    }

    public class CustomMessageRecover implements MethodInvocationRecoverer<Void> {

        @Override
        public Void recover(Object[] args, Throwable cause) {
            System.out.println("IN THE RECOVER ZONE!!!");
            throw new AmqpRejectAndDontRequeueException(cause);
        }
    }

    class EventException extends Exception {
        private static final long serialVersionUID = 1L;

        public EventException() {}

        public EventException(String message) {
            super(message);
        }
    }
}

Now in the code, as you can see I am using RetryOperationsInterceptor in order to intercept and check to see what type of exception it is being thrown and base on that, make the decision to either do the retry or not, along with the delay between the retries.

For this I am setting the backoffPolicy and retryPolicy of the RetryTemplate Bean and having that injected into the RetryOperationsInterceptor.

I would appreciate if anyone can help me out and tell me why the retry and the delay between the retries are not working. My messages are going directly to the dead letter exchange without the retries and the delays happening.

THANK YOU!

Answer 1

Your issue is here:

retryableExceptions.put(EventException.class, false);

Please, find the SimpleRetryPolicy code:

public boolean canRetry(RetryContext context) {
    Throwable t = context.getLastThrowable();
    return (t == null || retryForException(t)) && context.getRetryCount() < maxAttempts;
}

and further:

private boolean retryForException(Throwable ex) {
    return retryableClassifier.classify(ex);
}

Since you specify a false for your EventException, it won't be retryable. Hence any retries and backoffs.