Feign调用可重试的最佳方案分享

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface FeignRetry {

    Backoff backoff() default @Backoff();
    int maxAttempt() default 3;
    Class<? extends Throwable>[] include() default {};
}

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface Backoff {
    long delay() default 1000L;;
    long maxDelay() default 0L;
    double multiplier() default 0.0D;;
}

Slf4j
@Aspect
@Component
public class FeignRetryAspect {

    @Around("@annotation(FeignRetry)")
    public Object retry(ProceedingJoinPoint joinPoint) throws Throwable {
        Method method = getCurrentMethod(joinPoint);
        FeignRetry feignRetry = method.getAnnotation(FeignRetry.class);

        RetryTemplate retryTemplate = new RetryTemplate();
        retryTemplate.setBackOffPolicy(prepareBackOffPolicy(feignRetry));
        retryTemplate.setRetryPolicy(prepareSimpleRetryPolicy(feignRetry));

        // 重试
        return retryTemplate.execute(arg0 -> {
            int retryCount = arg0.getRetryCount();
            log.info("Sending request method: {}, max attempt: {}, delay: {}, retryCount: {}",
                    method.getName(),
                    feignRetry.maxAttempt(),
                    feignRetry.backoff().delay(),
                    retryCount
            );
            return joinPoint.proceed(joinPoint.getArgs());
        });
    }

    private BackOffPolicy prepareBackOffPolicy(FeignRetry feignRetry) {
        if (feignRetry.backoff().multiplier() != 0) {
            ExponentialBackOffPolicy backOffPolicy = new ExponentialBackOffPolicy();
            backOffPolicy.setInitialInterval(feignRetry.backoff().delay());
            backOffPolicy.setMaxInterval(feignRetry.backoff().maxDelay());
            backOffPolicy.setMultiplier(feignRetry.backoff().multiplier());
            return backOffPolicy;
        } else {
            FixedBackOffPolicy fixedBackOffPolicy = new FixedBackOffPolicy();
            fixedBackOffPolicy.setBackOffPeriod(feignRetry.backoff().delay());
            return fixedBackOffPolicy;
        }
    }


    private SimpleRetryPolicy prepareSimpleRetryPolicy(FeignRetry feignRetry) {
        Map<Class<? extends Throwable>, Boolean> policyMap = new HashMap<>();
        policyMap.put(RetryableException.class, true);  // Connection refused or time out
        policyMap.put(ClientException.class, true);     // Load balance does not available (cause of RunTimeException)
        if (feignRetry.include().length != 0) {
            for (Class<? extends Throwable> t : feignRetry.include()) {
                policyMap.put(t, true);
            }
        }
        return new SimpleRetryPolicy(feignRetry.maxAttempt(), policyMap, true);
    }

    private Method getCurrentMethod(JoinPoint joinPoint) {
        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        return signature.getMethod();
    }
}

@GetMapping
@FeignRetry(maxAttempt = 3, backoff = @Backoff(delay = 500L))
ResponseEntity<String> retrieve1();

@GetMapping
@FeignRetry(maxAttempt = 6, backoff = @Backoff(delay = 500L, maxDelay = 20000L, multiplier = 4))
ResponseEntity<String> retrieve2();