feign取消http请求重试

1.现状
目前所有应用调用用户中台采用feign接口，采用httpclient并且使用的是默认配置，目前主要的默认配置参数，参数所配置的超时时间太长，会导致大企业耗时比较长的接口会耗光所有资源（这些接口本身就需要优化，加分页等），导致其他企业的功能受到影响，所以需要对这些参数进行优化：
基本配置
connectTimeout 连接超时时间 10s
readTimeout 从服务器读取到资源所用时间 60s
automaticRetriesDisabled 是否取消重试 false，允许重试，重试次数默认3次
连接池配置
maxConnections 总的最大连接数 50
maxConnectionsPerRoute 每个路由的最大连接数 20（实际采用这个字段）
修改后的配置：
基本配置
connectTimeout 连接超时时间 3s
readTimeout 从服务器读取到资源所用时间 5s
automaticRetriesDisabled 是否取消重试 true，不重试
连接池配置
maxConnections 总的最大连接数 200
maxConnectionsPerRoute 每个路由的最大连接数 50（实际采用这个字段）
2.修改方案
feign配置httpclient在FeignAutoConfiguration类中，相关源码：

@Bean
@ConditionalOnMissingBean(HttpClientConnectionManager.class)
public HttpClientConnectionManager connectionManager(
      ApacheHttpClientConnectionManagerFactory connectionManagerFactory,
      FeignHttpClientProperties httpClientProperties) {
   final HttpClientConnectionManager connectionManager = connectionManagerFactory
         .newConnectionManager(httpClientProperties.isDisableSslValidation(), httpClientProperties.getMaxConnections(),
               httpClientProperties.getMaxConnectionsPerRoute(),
               httpClientProperties.getTimeToLive(),
               httpClientProperties.getTimeToLiveUnit(), registryBuilder);
   this.connectionManagerTimer.schedule(new TimerTask() {
      @Override      
      public void run() {
         connectionManager.closeExpiredConnections();
      }
   }, 30000, httpClientProperties.getConnectionTimerRepeat());
   return connectionManager;
}
@Bean
public CloseableHttpClient httpClient(ApacheHttpClientFactory httpClientFactory,
      HttpClientConnectionManager httpClientConnectionManager,
      FeignHttpClientProperties httpClientProperties) {
   RequestConfig defaultRequestConfig = RequestConfig.custom()
         .setConnectTimeout(httpClientProperties.getConnectionTimeout())
         .setRedirectsEnabled(httpClientProperties.isFollowRedirects())
         .build();
   this.httpClient = httpClientFactory.createBuilder().
         setConnectionManager(httpClientConnectionManager).
         setDefaultRequestConfig(defaultRequestConfig).build();
   return this.httpClient;
}
@Bean
@ConditionalOnMissingBean(Client.class)
public Client feignClient(HttpClient httpClient) {
   return new ApacheHttpClient(httpClient);
}

主要有三部分：
HttpClientConnectionManager 连接池管理器配置，主要是对连接池相关参数的配置
CloseableHttpClient httpclient相关配置，包括连接超时时间，读取超时时间等参数
ApacheHttpClient feign自定义的扩展Client，用包装器模式包装httpclient
所以如果需要修改feign上述的相关参数，就需要同时修改HttpClientConnectionManager，CloseableHttpClient和ApacheHttpClient，所以在AppWebConfig中可以增加如下代码：

/**
     * 设置feign连接池
     * @return
     */
    @Bean("feignHttpClientConnectionManager")
    public HttpClientConnectionManager httpClientConnectionManager(){
        DefaultApacheHttpClientConnectionManagerFactory connectionManagerFactory =
                new DefaultApacheHttpClientConnectionManagerFactory();
        final HttpClientConnectionManager connectionManager = connectionManagerFactory
                .newConnectionManager(false, 200,
                        50, 900, TimeUnit.SECONDS, null);
        /**
         * 关闭失效链接
         */
        ScheduledExecutorService scheduledExecutorService =
                new ScheduledThreadPoolExecutor(1);
        scheduledExecutorService.scheduleWithFixedDelay(()->connectionManager.closeExpiredConnections(), 30,10, TimeUnit.SECONDS);
        return connectionManager;
    }
    /**
     * 设置feign接口httpclient配置
     * @return
     */
    @Bean("feignHttpClient")
    public Client httpClient(HttpClientConnectionManager feignHttpClientConnectionManager) {
        /**
         * 设置参数
         * connectTimeout 3000ms
         * connectionRequestTimeout 1000ms
         * socketTimeout 5000ms
         */
        RequestConfig defaultRequestConfig = RequestConfig.custom()
                .setConnectTimeout(3000)
                .setConnectionRequestTimeout(1000)
                .setRedirectsEnabled(true)
                .setSocketTimeout(5000)
                .build();
        HttpClientBuilder httpClientBuilder = HttpClientBuilder.create();
        DefaultApacheHttpClientFactory httpClientFactory = new DefaultApacheHttpClientFactory(httpClientBuilder);
        /**
         * 取消重试
         */
        CloseableHttpClient httpClient = httpClientFactory.createBuilder().
                setConnectionManager(feignHttpClientConnectionManager).
                setDefaultRequestConfig(defaultRequestConfig)
                .disableAutomaticRetries()
                .build();
        return new ApacheHttpClient(httpClient);
    }

修改代码后进行测试发现，其中的ConnectTimeout和socketTimeout并没有生效，使用的还是系统默认值，分别为10和60s，追踪源码发现
（InternalHttpClient类）：

 final HttpRequestWrapper wrapper = HttpRequestWrapper.wrap(request, target);
            final HttpClientContext localcontext = HttpClientContext.adapt(
                    context != null ? context : new BasicHttpContext());
            RequestConfig config = null;
            if (request instanceof Configurable) {
                config = ((Configurable) request).getConfig();
            }
            if (config == null) {
                final HttpParams params = request.getParams();
                if (params instanceof HttpParamsNames) {
                    if (!((HttpParamsNames) params).getNames().isEmpty()) {
                        config = HttpClientParamConfig.getRequestConfig(params, this.defaultConfig);
                    }
                } else {
                    config = HttpClientParamConfig.getRequestConfig(params, this.defaultConfig);
                }
            }
            if (config != null) {
                localcontext.setRequestConfig(config);
            }
            setupContext(localcontext);
            final HttpRoute route = determineRoute(target, wrapper, localcontext);
            return this.execChain.execute(route, wrapper, localcontext, execAware);

先使用的是请求request里面的参数，当参数未设置时才使用的是httpclient配置的参数，向上跟踪源码ApacheHttpClient类

 @Override
  public Response execute(Request request, Request.Options options) throws IOException {
    HttpUriRequest httpUriRequest;
    try {
      httpUriRequest = toHttpUriRequest(request, options);
    } catch (URISyntaxException e) {
      throw new IOException("URL '" + request.url() + "' couldn't be parsed into a URI", e);
    }
    HttpResponse httpResponse = client.execute(httpUriRequest);
    return toFeignResponse(httpResponse).toBuilder().request(request).build();
  }
  HttpUriRequest toHttpUriRequest(Request request, Request.Options options) throws
          UnsupportedEncodingException, MalformedURLException, URISyntaxException {
    RequestBuilder requestBuilder = RequestBuilder.create(request.method());
    //per request timeouts
    RequestConfig requestConfig = RequestConfig
            .custom()
            .setConnectTimeout(options.connectTimeoutMillis())
            .setSocketTimeout(options.readTimeoutMillis())
            .build();
    requestBuilder.setConfig(requestConfig);
      .......

HttpUriRequest对Request进行包装，将options设置的参数赋值给Request，从而改变请求的参数，options生成有两种：通过配置（FeignClientProperties类）和通过@Bean生成
1.配置
feign:
client:
config:
athena: #服务名，填写default为所有服务
connectTimeout: 3000
readTimeout: 5000
注：athena为服务名，也就是feign接口FeignClient注解配置的name的名称，如果填写default则默认对所有服务有效
@FeignClient(name = "athena", url = "${feign.athena.server}", configuration = UserFeignConfig.class)
2.设置feign超时时间

/**
     * feign接口参数
     * @return
     */
    @Bean
    public Request.Options options() {
        return new Request.Options(3000, 5000);
    }

该配置对所有的服务有效，和方法1中配置default效果一致
3.最终修改方案

 /**
     * 设置feign连接池
     * @return
     */
    @Bean("feignHttpClientConnectionManager")
    public HttpClientConnectionManager httpClientConnectionManager(){
        DefaultApacheHttpClientConnectionManagerFactory connectionManagerFactory =
                new DefaultApacheHttpClientConnectionManagerFactory();
        final HttpClientConnectionManager connectionManager = connectionManagerFactory
                .newConnectionManager(false, 200,
                        50, 900, TimeUnit.SECONDS, null);
        /**
         * 关闭失效链接
         */
        ScheduledExecutorService scheduledExecutorService =
                new ScheduledThreadPoolExecutor(1);
        scheduledExecutorService.scheduleWithFixedDelay(()->connectionManager.closeExpiredConnections(), 30,10, TimeUnit.SECONDS);
        return connectionManager;
    }
    /**
     * 设置feign接口httpclient配置
     * @return
     */
    @Bean("feignHttpClient")
    public Client httpClient(HttpClientConnectionManager feignHttpClientConnectionManager) {
        /**
         * 设置参数
         * connectTimeout 3000ms
         * connectionRequestTimeout 1000ms
         * socketTimeout 5000ms
         */
        RequestConfig defaultRequestConfig = RequestConfig.custom()
                .setConnectTimeout(3000)
                .setConnectionRequestTimeout(1000)
                .setRedirectsEnabled(true)
                .setSocketTimeout(5000)
                .build();
        HttpClientBuilder httpClientBuilder = HttpClientBuilder.create();
        DefaultApacheHttpClientFactory httpClientFactory = new DefaultApacheHttpClientFactory(httpClientBuilder);
        /**
         * 取消重试
         */
        CloseableHttpClient httpClient = httpClientFactory.createBuilder().
                setConnectionManager(feignHttpClientConnectionManager).
                setDefaultRequestConfig(defaultRequestConfig)
                .disableAutomaticRetries()
                .build();
        return new ApacheHttpClient(httpClient);
    }
    /**
     * feign接口参数
     * @return
     */
    @Bean
    public Request.Options options() {
        return new Request.Options(3000, 5000);
    }