circuit breaker can be called without affecting the state.

Resilience4j version: 1.3.1

Java version: 1.8

I just want to know the circuit breakers status. ex) is open or half-open and can call backend). so I used tryAcquirePermission(). but I missed the comment below.

     * Important: Make sure to call onSuccess or onError after the call is finished.
     * If the call is canceled before it is invoked, you have to release the permission again.

so everything is looks fine until the circuit breaker is half-open. when circuit breaker is half-open, to call tryAcquirePermission is effect permittedNumberOfCallsInHalfOpenState. ( Using this method affects this property.) if call count reached permittedNumberOfCallsInHalfOpenState, circuit breaker stuck half-open

I think need to make a method to check to call permitted a backend service. If possible, I want to make it.

[RobWin]

You can create a method like this:

private <T> Mono<T> executeWithFallback(Mono<T> publisher, Function<Throwable, Mono<T>> fallback){
        return publisher
                .transform(TimeLimiterOperator.of(timeLimiter))
                .transform(CircuitBreakerOperator.of(circuitBreaker))
                .onErrorResume(TimeoutException.class, fallback)
                .onErrorResume(CallNotPermittedException.class, fallback);
    }

The fallback can be your message to the user.

Mono<T> result = executeWithFallback(() -> yourService.method(), () ->  Mono.empty());

[RobWin]

This is not how you should use the CircuitBreaker. The exception from the CircuitBreaker tells you that it is open, just map the exception to a proper response to the user. Please don’t do it that way. There is usually no need to use this CircuitBreakerUtil class.