Manually creating a circuit-breaker-wrapped feign client

Question

I'm trying to manually create a circuit-breaker-wrapped Feign client, so that I can use callbacks. I understand that there's another approach that kind of simplify this, which is using the @FeignClient annotation, as well as enabling fallbacks with feign.circuitbreaker.enabled=true and importing the spring-cloud-starter-circuitbreaker-resilience4j dependency. Unfortunately this does not solve our problem, we need to manually create them (with code).

Below is how I'm creating a simple Feign client:

@Bean
public SomeClient client() {
    Request.Options options = new Request.Options(1000L, TimeUnit.MILLISECONDS, 3000L, TimeUnit.MILLISECONDS, false);

    return Feign.builder()
            .options(options)
            .contract(new SpringMvcContract())
            .target(SomeClient.class, "some_url");
}

Looking at the Spring's FeignClientsConfiguration class, I found the piece of code responsible of enabling the circuit breaker, which is:

@Configuration(proxyBeanMethods = false)
@ConditionalOnClass({ CircuitBreaker.class })
@ConditionalOnProperty({ "feign.circuitbreaker.enabled" })
protected static class CircuitBreakerPresentFeignBuilderConfiguration {

    @Bean
    @Scope("prototype")
    @ConditionalOnMissingBean({ Builder.class, CircuitBreakerFactory.class })
    public Builder defaultFeignBuilder(Retryer retryer) {
        return Feign.builder().retryer(retryer);
    }

    @Bean
    @Scope("prototype")
    @ConditionalOnMissingBean
    @ConditionalOnBean({ CircuitBreakerFactory.class })
    public Builder circuitBreakerFeignBuilder() {
        return FeignCircuitBreaker.builder();
    }
    
}

After that, I tried changing from Feign.builder() to FeignCircuitBreaker.builder() within our client bean method, as it supports the T target(Target<T> target, T fallback) method, although no luck on that: some weird null pointer exception at org.springframework.cloud.openfeign.FeignCircuitBreakerInvocationHandler.invoke(FeignCircuitBreakerInvocationHandler.java:88).

Looking at the FeignClientsConfiguration class again, the circuitBreakerFeignBuilder method depends on the CircuitBreakerFactory bean, which is supposedly not being created automatically, so I tried creating one, but this just gets things even more complicated.

I couldn't find much information regarding this issue on the internet, hopefully someone knows how to solve this.

Manually creating a circuit-breaker-wrapped feign client

0 Answers0