SpringCloud微服務(wù)調(diào)用丟失請求頭的問題及解決方案

更新時間：2024年02月20日 14:31:26 作者：曬干的老咸魚

在Spring Cloud 中微服務(wù)之間的調(diào)用會用到Feign,但是在默認(rèn)情況下,Feign 調(diào)用遠(yuǎn)程服務(wù)存在Header請求頭丟失問題,下面給大家分享SpringCloud微服務(wù)調(diào)用丟失請求頭的問題及解決方案,感興趣的朋友一起看看吧

在 Spring Cloud 中微服務(wù)之間的調(diào)用會用到Feign，但是在默認(rèn)情況下，F(xiàn)eign 調(diào)用遠(yuǎn)程服務(wù)存在Header請求頭丟失問題。但基本上每個服務(wù)都會有一個全局globalId，能夠清除調(diào)用鏈路，可以有兩種解決方案

解決方案一

可以在每次遠(yuǎn)程調(diào)用時，使用@RequestHeader注解重新封裝請求頭

    @GetMapping("/test")
    String test(String res, @RequestHeader String globalId);

解決方案二

可以使用springcloud提供的feign攔截器RequestInterceptor，攔截請求頭重新進(jìn)行封裝

package com.test.feignheader.config;
import feign.RequestInterceptor;
import feign.RequestTemplate;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import javax.servlet.http.HttpServletRequest;
/**
 * @Description: feign攔截器功能, 解決header丟失問題
 **/
@Configuration
public class FeignConfig {
    @Bean("requestInterceptor")
    public RequestInterceptor requestInterceptor() {
        RequestInterceptor requestInterceptor = new RequestInterceptor() {
            @Override
            public void apply(RequestTemplate template) {
                //1、使用RequestContextHolder拿到剛進(jìn)來的請求數(shù)據(jù)
                ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
                if (requestAttributes != null) {
                    //老請求
                    HttpServletRequest request = requestAttributes.getRequest();
                    if (request != null) {
                        //2、同步請求頭的數(shù)據(jù)（主要是cookie）
                        //把老請求的cookie值放到新請求上來，進(jìn)行一個同步
                        String cookie = request.getHeader("Cookie");
                        template.header("Cookie", cookie);
                    }
                }
            }
        };
        return requestInterceptor;
    }
}

也可以參考下面的代碼進(jìn)行封裝

public class FeignBasicAuthRequestInterceptor implements RequestInterceptor {
    private static final Logger logger = LoggerFactory.getLogger(FeignBasicAuthRequestInterceptor.class);
    @Override
    public void apply(RequestTemplate requestTemplate) {
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder
                .getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();
        Enumeration<String> headerNames = request.getHeaderNames();
        if (headerNames != null) {
            while (headerNames.hasMoreElements()) {
                String name = headerNames.nextElement();
                String values = request.getHeader(name);
                //跳過 content-length，避免追加參數(shù)導(dǎo)致content-length值與實(shí)際長度不一樣
                if (name.equals("content-length")) {
                   continue;
                }
                requestTemplate.header(name, values);
            }
        }
        /**  body一般不需要處理，否則會導(dǎo)致微服務(wù)調(diào)用異常
        Enumeration<String> bodyNames = request.getParameterNames();
        StringBuffer body =new StringBuffer();
        if (bodyNames != null) {
            while (bodyNames.hasMoreElements()) {
                String name = bodyNames.nextElement();
                String values = request.getParameter(name);
                body.append(name).append("=").append(values).append("&");
            }
        }
        if(body.length()!=0) {
            body.deleteCharAt(body.length()-1);
            requestTemplate.body(body.toString());
            logger.info("feign interceptor body:{}",body.toString());
        }
        */
    }
}

配置讓所有 FeignClient，使用 FeignBasicAuthRequestInterceptor

feign:
  client:
    config:
      default:
        connectTimeout: 5000
        readTimeout: 5000
        loggerLevel: basic
        requestInterceptors: com.leparts.config.FeignBasicAuthRequestInterceptor

也可以配置讓某個 FeignClient 使用這個 FeignBasicAuthRequestInterceptor

feign:
  client:
    config:
      xxxx: # 遠(yuǎn)程服務(wù)名
        connectTimeout: 5000
        readTimeout: 5000
        loggerLevel: basic
        requestInterceptors: com.leparts.config.FeignBasicAuthRequestInterceptor

經(jīng)過測試，上面的解決方案可以正常的使用；但是出現(xiàn)了新的問題。

在轉(zhuǎn)發(fā)Feign的請求頭的時候, 如果開啟了Hystrix, Hystrix的默認(rèn)隔離策略是Thread(線程隔離策略), 因此轉(zhuǎn)發(fā)攔截器內(nèi)是無法獲取到請求的請求頭信息的。

可以修改默認(rèn)隔離策略為信號量模式：

hystrix.command.default.execution.isolation.strategy=SEMAPHORE

但信號量模式不是官方推薦的隔離策略;另一個解決方法就是自定義Hystrix的隔離策略。

自定義策略

HystrixConcurrencyStrategy 是提供給開發(fā)者去自定義hystrix內(nèi)部線程池及其隊(duì)列，還提供了包裝callable的方法，以及傳遞上下文變量的方法。所以可以繼承了HystrixConcurrencyStrategy，用來實(shí)現(xiàn)了自己的并發(fā)策略。

@Component
public class FeignHystrixConcurrencyStrategy extends HystrixConcurrencyStrategy {
    private static final Logger log = LoggerFactory.getLogger(FeignHystrixConcurrencyStrategy.class);
    private HystrixConcurrencyStrategy delegate;
    public FeignHystrixConcurrencyStrategy() {
        try {
            this.delegate = HystrixPlugins.getInstance().getConcurrencyStrategy();
            if (this.delegate instanceof FeignHystrixConcurrencyStrategy) {
                // Welcome to singleton hell...
                return;
            }
            HystrixCommandExecutionHook commandExecutionHook =
                    HystrixPlugins.getInstance().getCommandExecutionHook();
            HystrixEventNotifier eventNotifier = HystrixPlugins.getInstance().getEventNotifier();
            HystrixMetricsPublisher metricsPublisher = HystrixPlugins.getInstance().getMetricsPublisher();
            HystrixPropertiesStrategy propertiesStrategy =
                    HystrixPlugins.getInstance().getPropertiesStrategy();
            this.logCurrentStateOfHystrixPlugins(eventNotifier, metricsPublisher, propertiesStrategy);
            HystrixPlugins.reset();
            HystrixPlugins instance = HystrixPlugins.getInstance();
            instance.registerConcurrencyStrategy(this);
            instance.registerCommandExecutionHook(commandExecutionHook);
            instance.registerEventNotifier(eventNotifier);
            instance.registerMetricsPublisher(metricsPublisher);
            instance.registerPropertiesStrategy(propertiesStrategy);
        } catch (Exception e) {
            log.error("Failed to register Sleuth Hystrix Concurrency Strategy", e);
        }
    }
    private void logCurrentStateOfHystrixPlugins(HystrixEventNotifier eventNotifier,
                                                 HystrixMetricsPublisher metricsPublisher,
                                                 HystrixPropertiesStrategy propertiesStrategy) {
        if (log.isDebugEnabled()) {
            log.debug("Current Hystrix plugins configuration is [" + "concurrencyStrategy ["
                    + this.delegate + "]," + "eventNotifier [" + eventNotifier + "]," + "metricPublisher ["
                    + metricsPublisher + "]," + "propertiesStrategy [" + propertiesStrategy + "]," + "]");
            log.debug("Registering Sleuth Hystrix Concurrency Strategy.");
        }
    }
    @Override
    public <T> Callable<T> wrapCallable(Callable<T> callable) {
        RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
        return new WrappedCallable<>(callable, requestAttributes);
    }
    @Override
    public ThreadPoolExecutor getThreadPool(HystrixThreadPoolKey threadPoolKey,
                                            HystrixProperty<Integer> corePoolSize,
                                            HystrixProperty<Integer> maximumPoolSize,
                                            HystrixProperty<Integer> keepAliveTime,
                                            TimeUnit unit, BlockingQueue<Runnable> workQueue) {
        return this.delegate.getThreadPool(threadPoolKey, corePoolSize, maximumPoolSize, keepAliveTime,
                unit, workQueue);
    }
    @Override
    public ThreadPoolExecutor getThreadPool(HystrixThreadPoolKey threadPoolKey,
                                            HystrixThreadPoolProperties threadPoolProperties) {
        return this.delegate.getThreadPool(threadPoolKey, threadPoolProperties);
    }
    @Override
    public BlockingQueue<Runnable> getBlockingQueue(int maxQueueSize) {
        return this.delegate.getBlockingQueue(maxQueueSize);
    }
    @Override
    public <T> HystrixRequestVariable<T> getRequestVariable(HystrixRequestVariableLifecycle<T> rv) {
        return this.delegate.getRequestVariable(rv);
    }
    static class WrappedCallable<T> implements Callable<T> {
        private final Callable<T> target;
        private final RequestAttributes requestAttributes;
        WrappedCallable(Callable<T> target, RequestAttributes requestAttributes) {
            this.target = target;
            this.requestAttributes = requestAttributes;
        }
        @Override
        public T call() throws Exception {
            try {
                RequestContextHolder.setRequestAttributes(requestAttributes);
                return target.call();
            } finally {
                RequestContextHolder.resetRequestAttributes();
            }
        }
    }
}

致此，F(xiàn)eign調(diào)用丟失請求頭的問題就解決的了。

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