使用 reactiveFeignClient 和 CircuitBreaker 進行錯誤處理

Question

我們正在使用反應式偽裝客戶端（com.playtika.reactivefeign:feign-reactor-spring-cloud-starter:3.2.0）

斷路器版本：org.springframework.cloud:spring-cloud-starter-circuitbreaker-reactor-resilience4j:2.1.0

和 spring boot 應用程序版本 org.springframework.boot' version '2.6.6

當我們從反應式偽裝客戶端收到錯誤（例如 404 錯誤）時

@ReactiveFeignClient(name = "someRestClient", url = "${react-gpi-service.url}",configuration = AuthConfigurationsomeRestClient.class, fallbackFactory = someRestClienttFallbackFactory.class)
@Profile("!test")
public interface someRestClient {
@PostMapping(value = "/v2/{entity}/any", produces = MediaType.ALL_VALUE, consumes = MediaType.APPLICATION_JSON_VALUE)
 Mono<String> any(@PathVariable(value = "entity")

它遍歷錯誤解碼器以檢查是否應該重試

@Slf4j
@RequiredArgsConstructor
public class RetryableErrorDecoder implements ErrorDecoder {

    private static ErrorDecoder defaultErrorDecoder = new Default();
    private final String clientName;

    public Exception decode(String methodKey, Response response) {
        String body = "";
        try {
            body = IOUtils.toString(response.body().asInputStream(), StandardCharsets.UTF_8);
        } catch (Exception e) {
            log.error("failed to parse error response body", e);
        }

        log.error("In RetryableErrorDecoder, got an error from {}. status: {}, body: {}, reason: {}, request: {}",
                clientName, response.status(), body, response.reason(), response.request());

        if (response.status() == HttpStatusCodes.STATUS_CODE_SERVICE_UNAVAILABLE ||
                response.status() == HttpStatusCodes.STATUS_CODE_BAD_GATEWAY) {
            log.warn("Retry on error 503 or 502");
            return createRetryableException(response, "Service Unavailable 503, 502");
        } else {
            Exception decode = defaultErrorDecoder.decode(methodKey, response);
            if (decode instanceof FeignException &&
                    decode.getMessage().contains("authorizing")) {
                log.warn("Retry on {}", decode.getMessage());
                return createRetryableException(response, "Service authorizing problem");
            }
            return decode;
        }
    }

    private Exception createRetryableException(Response response, String message) {
        return new RetryableException(
                response.status(),
                message,
                response.request().httpMethod(),
                null,
                null,
                response.request());
    }
}

之后它轉到 Circuit beaker predicate

public class someFailurePredicate  implements Predicate<Throwable> {

    @Override
    public boolean test(Throwable throwable) {
        return throwable instanceof ThirdPartyException
                || throwable instanceof ReadTimeoutException
                || throwable instanceof OutOfRetriesException;
    }
}

然后進入 fallBackFactory 機制，因為斷路器需要 fallback 方法，所以斷路器謂詞再次被激活。

@Component
public class someRestClientFallbackFactory implements FallbackFactory<someRestClient> {

    @Override
    public someRestClient apply(Throwable throwable) {
        return new someRestClientFallback(throwable);
    }
}

public class someRestClientFallback implements someRestClient {

    private final Throwable cause;

    public someClientFallback(Throwable cause) {
        this.cause = cause;
    }

    public Mono<String> performSearchRequest(String entity,
                                                     ) {
        return Mono.error(cause);
    }
}

因為我們有兩種錯誤處理機制，電路謂詞調用兩次並復制錯誤。

我試圖將重試機制（錯誤解碼器）移至回退方法，但回退工廠方法接受可拋出的並且 reactiveFeignClientException 沒有狀態代碼，因此很難確定我們是否應該進行重試。

如果我刪除后備方法，我會收到此錯誤消息：

org.springframework.cloud.client.circuitbreaker.NoFallbackAvailableException: No fallback available.

我們需要添加它，但是我們有兩個機制和一個重復的斷路器謂詞計數

Answer 1

Reactive Feign Client 默認啟用自己的 CB，可以通過將 reactive.feign.circuit.breaker.enabled 設置為 false 來禁用它 - https://github.com/PlaytikaOSS/feign-reactive/blob/develop/feign-反應堆彈簧配置/README.md