quarkus: Exceptions thrown in Rest client should be more specific

Description

Currently when using the Quarkus rest client (regular & reactive), any response other than a 2xx is thrown as a javax.ws.rs.WebApplicationException (or a RESTEasy subclass of it). In Quarkus using RESTEasy Reactive, the exception is a org.jboss.resteasy.reactive.ClientWebApplicationException, which is a subclass of javax.ws.rs.WebApplicationException. JAX-RS exposes more fine-grained exceptions for lots of http statuses.

Because of this, using fault tolerance handling is very difficult, as you aren’t able to use the built-in skipOn fields in the fault tolerance annotations.

Say I want to ignore a circuit breaker/fallback/retry on a specific http status? I can’t use the fault tolerance exception because everything is always a javax.ws.rs.WebApplicationException.

As an example, say I want to ignore a circuit breaker if a client call returns a 404. I have to implement some custom logic:

HeroRestClient.java:

@Path("/api/heroes")
@Produces(MediaType.APPLICATION_JSON)
@RegisterRestClient(configKey = "hero-client")
interface HeroRestClient {
  @GET
  @Path("/random")
  Uni<Hero> findRandomHero();
}

HeroClient.java:

@ApplicationScoped
public class HeroClient {
  private final HeroRestClient heroClient;

  public HeroClient(@RestClient HeroRestClient heroClient) {
    this.heroClient = heroClient;
  }

  @CircuitBreaker(requestVolumeThreshold = 8, failureRatio = 0.5, delay = 2, delayUnit = ChronoUnit.SECONDS)
  @CircuitBreakerName("findRandomHero")
  CompletionStage<Hero> getRandomHero() {
    // Want the 404 handling to be part of the circuit breaker
    // This means that the 404 responses aren't considered errors by the circuit breaker
    return this.heroClient.findRandomHero()
      .onFailure(throwable -> 
        Optional.ofNullable(throwable)
          .filter(t -> t instanceof WebApplicationException)
          .map(WebApplicationException.class::cast)
          .map(WebApplicationException::getResponse)
          .filter(response -> response.getStatus() == Status.NOT_FOUND.getStatusCode())
          .isPresent()
      ).recoverWithNull()
      .subscribeAsCompletionStage();
  }
}

When the JAX-RS spec already has exceptions that map to most of the known http status codes. If that was the case, then my custom code could be completely replaced with something like

@Path("/api/heroes")
@Produces(MediaType.APPLICATION_JSON)
@RegisterRestClient(configKey = "hero-client")
interface HeroRestClient {
  @GET
  @Path("/random")
  @CircuitBreaker(
    requestVolumeThreshold = 8, 
    failureRatio = 0.5, 
    delay = 2, 
    delayUnit = ChronoUnit.SECONDS,
    skipOn = NotFoundException.class
  )
  @CircuitBreakerName("findRandomHero")
  Uni<Hero> findRandomHero();
}

See https://github.com/smallrye/smallrye-fault-tolerance/issues/524#issuecomment-1061891842 for some conversation around this as well.

Implementation ideas

No response