真实的国产乱ⅩXXX66竹夫人,五月香六月婷婷激情综合,亚洲日本VA一区二区三区,亚洲精品一区二区三区麻豆

成都創(chuàng)新互聯(lián)網(wǎng)站制作重慶分公司

詳解feign調(diào)用session丟失解決方案

最近在做項(xiàng)目的時(shí)候發(fā)現(xiàn),微服務(wù)使用feign相互之間調(diào)用時(shí),存在session丟失的問(wèn)題。例如,使用Feign調(diào)用某個(gè)遠(yuǎn)程API,這個(gè)遠(yuǎn)程API需要傳遞一個(gè)鑒權(quán)信息,我們可以把cookie里面的session信息放到Header里面,這個(gè)Header是動(dòng)態(tài)的,跟你的HttpRequest相關(guān),我們選擇編寫(xiě)一個(gè)攔截器來(lái)實(shí)現(xiàn)Header的傳遞,也就是需要實(shí)現(xiàn)RequestInterceptor接口,具體代碼如下:

創(chuàng)新互聯(lián)是少有的網(wǎng)站建設(shè)、做網(wǎng)站、營(yíng)銷型企業(yè)網(wǎng)站、小程序定制開(kāi)發(fā)、手機(jī)APP,開(kāi)發(fā)、制作、設(shè)計(jì)、賣(mài)友情鏈接、推廣優(yōu)化一站式服務(wù)網(wǎng)絡(luò)公司,2013年至今,堅(jiān)持透明化,價(jià)格低,無(wú)套路經(jīng)營(yíng)理念。讓網(wǎng)頁(yè)驚喜每一位訪客多年來(lái)深受用戶好評(píng)

@Configuration 
@EnableFeignClients(basePackages = "com.xxx.xxx.client") 
public class FeignClientsConfigurationCustom implements RequestInterceptor { 
 
 @Override 
 public void apply(RequestTemplate template) { 
 
  RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes(); 
  if (requestAttributes == null) { 
   return; 
  } 
 
  HttpServletRequest request = ((ServletRequestAttributes) requestAttributes).getRequest(); 
  Enumeration headerNames = request.getHeaderNames(); 
  if (headerNames != null) { 
   while (headerNames.hasMoreElements()) { 
    String name = headerNames.nextElement(); 
    Enumeration values = request.getHeaders(name); 
    while (values.hasMoreElements()) { 
     String value = values.nextElement(); 
     template.header(name, value); 
    } 
   } 
  } 
 
 } 
 
} 

經(jīng)過(guò)測(cè)試,上面的解決方案可以正常的使用; 

但是,當(dāng)引入Hystrix熔斷策略時(shí),出現(xiàn)了一個(gè)新的問(wèn)題:

RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();

此時(shí)requestAttributes會(huì)返回null,從而無(wú)法傳遞session信息,最終發(fā)現(xiàn)RequestContextHolder.getRequestAttributes(),該方法是從ThreadLocal變量里面取得對(duì)應(yīng)信息的,這就找到問(wèn)題原因了,是由于Hystrix熔斷機(jī)制導(dǎo)致的。 
Hystrix有2個(gè)隔離策略:THREAD以及SEMAPHORE,當(dāng)隔離策略為 THREAD 時(shí),是沒(méi)辦法拿到 ThreadLocal 中的值的。

因此有兩種解決方案:

方案一:調(diào)整格隔離策略:

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

這樣配置后,F(xiàn)eign可以正常工作。

但該方案不是特別好。原因是Hystrix官方強(qiáng)烈建議使用THREAD作為隔離策略! 可以參考官方文檔說(shuō)明。

方案二:自定義策略

記得之前在研究zipkin日志追蹤的時(shí)候,看到過(guò)Sleuth有自己的熔斷機(jī)制,用來(lái)在thread之間傳遞Trace信息,Sleuth是可以拿到自己上下文信息的,查看源碼找到了 
org.springframework.cloud.sleuth.instrument.hystrix.SleuthHystrixConcurrencyStrategy 
這個(gè)類,查看SleuthHystrixConcurrencyStrategy的源碼,繼承了HystrixConcurrencyStrategy,用來(lái)實(shí)現(xiàn)了自己的并發(fā)策略。

/**
 * Abstract class for defining different behavior or implementations for concurrency related aspects of the system with default implementations.
 * 

* For example, every {@link Callable} executed by {@link HystrixCommand} will call {@link #wrapCallable(Callable)} to give a chance for custom implementations to decorate the {@link Callable} with * additional behavior. *

* When you implement a concrete {@link HystrixConcurrencyStrategy}, you should make the strategy idempotent w.r.t ThreadLocals. * Since the usage of threads by Hystrix is internal, Hystrix does not attempt to apply the strategy in an idempotent way. * Instead, you should write your strategy to work idempotently. See https://github.com/Netflix/Hystrix/issues/351 for a more detailed discussion. *

* See {@link HystrixPlugins} or the Hystrix GitHub Wiki for information on configuring plugins: https://github.com/Netflix/Hystrix/wiki/Plugins. */ public abstract class HystrixConcurrencyStrategy

搜索發(fā)現(xiàn)有好幾個(gè)地方繼承了HystrixConcurrencyStrategy類 

詳解feign調(diào)用session丟失解決方案

其中就有我們熟悉的Spring Security和剛才提到的Sleuth都是使用了自定義的策略,同時(shí)由于Hystrix只允許有一個(gè)并發(fā)策略,因此為了不影響Spring Security和Sleuth,我們可以參考他們的策略實(shí)現(xiàn)自己的策略,大致思路: 

將現(xiàn)有的并發(fā)策略作為新并發(fā)策略的成員變量; 

在新并發(fā)策略中,返回現(xiàn)有并發(fā)策略的線程池、Queue; 

代碼如下:

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.getInstance().registerConcurrencyStrategy(this); 
   HystrixPlugins.getInstance().registerCommandExecutionHook(commandExecutionHook); 
   HystrixPlugins.getInstance().registerEventNotifier(eventNotifier); 
   HystrixPlugins.getInstance().registerMetricsPublisher(metricsPublisher); 
   HystrixPlugins.getInstance().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  Callable wrapCallable(Callable callable) { 
  RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes(); 
  return new WrappedCallable<>(callable, requestAttributes); 
 } 
 
 @Override 
 public ThreadPoolExecutor getThreadPool(HystrixThreadPoolKey threadPoolKey, 
   HystrixProperty corePoolSize, HystrixProperty maximumPoolSize, 
   HystrixProperty keepAliveTime, TimeUnit unit, BlockingQueue 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 getBlockingQueue(int maxQueueSize) { 
  return this.delegate.getBlockingQueue(maxQueueSize); 
 } 
 
 @Override 
 public  HystrixRequestVariable getRequestVariable(HystrixRequestVariableLifecycle rv) { 
  return this.delegate.getRequestVariable(rv); 
 } 
 
 static class WrappedCallable implements Callable { 
  private final Callable target; 
  private final RequestAttributes requestAttributes; 
 
  public WrappedCallable(Callable 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(); 
   } 
  } 
 } 
} 

最后,將這個(gè)策略類作為bean配置到feign的配置類FeignClientsConfigurationCustom中

 @Bean
 public FeignHystrixConcurrencyStrategy feignHystrixConcurrencyStrategy() {
  return new FeignHystrixConcurrencyStrategy();
 }

至此,結(jié)合FeignClientsConfigurationCustom配置feign調(diào)用session丟失的問(wèn)題完美解決。

以上就是本文的全部?jī)?nèi)容,希望對(duì)大家的學(xué)習(xí)有所幫助,也希望大家多多支持創(chuàng)新互聯(lián)。 


網(wǎng)站題目:詳解feign調(diào)用session丟失解決方案
瀏覽地址:http://weahome.cn/article/ghcccp.html

其他資訊

在線咨詢

微信咨詢

電話咨詢

028-86922220(工作日)

18980820575(7×24)

提交需求

返回頂部