Use resilience4j CircutiBreaker with Retry module

Question

to make the application fault tolerant, wanted to combine Retry mechanism along with CircuitBreaker of resilience4j.

I'm trying to achieve this "When in a single CircuitBreaker call, the Retry failures exceeds the CircuitBreaker failuretRateThreshold, then the CircuitBreaker should trip to OPEN state, but it is not happening.

RetryConfig retryconfig = RetryConfig.<String>custom()
                .intervalFunction(intervalWithCustomExponentialRandomBackoff)
                .maxAttempts(10)
                .ignoreExceptions(IOException.class)
                .retryOnException(e -> e instanceof HttpClientErrorException)
                .build();
        RetryRegistry retryregistry = RetryRegistry.of(retryconfig);
        Retry retry = retryregistry.retry("serviceA",retryconfig);

        CircuitBreakerConfig config = CircuitBreakerConfig
                .custom()
                .slidingWindowType(CircuitBreakerConfig.SlidingWindowType.COUNT_BASED)
                .minimumNumberOfCalls(5)
                .slidingWindowSize(10)
                .failureRateThreshold(50.0f)
                .permittedNumberOfCallsInHalfOpenState(3)
                .waitDurationInOpenState(Duration.ofSeconds(30))
                .writableStackTraceEnabled(false)
                .recordException((Throwable e) -> {
                    if (e instanceof HttpClientErrorException) {
                        HttpClientErrorException httpException = (HttpClientErrorException) e;
                        return (Arrays.asList(HttpStatus.GATEWAY_TIMEOUT, HttpStatus.BAD_REQUEST).contains(httpException.getStatusCode()));
                    } else if (e instanceof HttpServerErrorException) {
                        return true;
                    } else {
                        return false;
                    }
                })
                .build();
        CircuitBreakerRegistry registry = CircuitBreakerRegistry.of(config);
        CircuitBreaker circuitBreaker = registry.circuitBreaker("serviceA");

        String url = BASE_URL + "b";

        Supplier<String> retrySupplier = () -> restTemplate.getForObject(
                url,
                String.class
        );
        Supplier<String> decoratedCircuitSupplier = CircuitBreaker.decorateSupplier(circuitBreaker, Retry.decorateSupplier(retry, retrySupplier));
decoratedCircuitSupplier.get() // this will call the other service (serviceB). Here as the serviceB is down, the response code will be 504.

excepectation as per my understanding: the Retry will do retries for 10 calls, but all of them fail with 504. As the CircuitBreaker also considers 504 as exception, CircuitBreaker should change to OPEN state upon 5 failures of the calls based on configuration.

what is happening: Retry keeps calling serviceB for 10 times, and CircuitBreaker remains in CLSOED state only.

Answer 1

https://resilience4j.readme.io/docs/getting-started-3#aspect-order quoting from the documentation The Resilience4j Aspects order is the following: Retry ( CircuitBreaker ( RateLimiter ( TimeLimiter ( Bulkhead ( Function ) ) ) ) ) so Retry is applied at the end (if needed). If you need a different order, you must use the functional chaining style instead of the Spring annotations style or explicitly set aspect order using the following properties:

so the code is working as designed, once all the retries are exhausted only then the circuit breaker will flip its state.