springcloud zuul

最新推荐文章于 2023-05-13 00:45:00 发布

原创最新推荐文章于 2023-05-13 00:45:00 发布 · 140 阅读

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本文深入解析Spring Cloud Zuul路由网关的工作原理，详细介绍了ZuulServlet的加载过程，以及ZuulRunner和FilterProcessor的执行逻辑。通过分析ZuulFilter的注册与调用流程，揭示了Zuul路由规则的实现机制。

环境启动的时候会通过springboot加载自动配置 org.springframework.cloud.netflix.zuul.ZuulServerAutoConfiguration#zuulServlet

执行此方法，会将zuulServlet 加载到springweb中

zuulServlet 的路径配置，默认是/*

Servet中的代码如下

public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
    try {
        this.init((HttpServletRequest)servletRequest, (HttpServletResponse)servletResponse);
        RequestContext e = RequestContext.getCurrentContext();
        e.setZuulEngineRan();

        try {
            this.preRoute();
        } catch (ZuulException var13) {
            this.error(var13);
            this.postRoute();
            return;
        }
        try {
            this.route();
        } catch (ZuulException var12) {
            this.error(var12);
            this.postRoute();
            return;
        }
        try {
            this.postRoute();
        } catch (ZuulException var11) {
            this.error(var11);
        }
    } catch (Throwable var14) {
        this.error(new ZuulException(var14, 500, "UNHANDLED_EXCEPTION_" + var14.getClass().getName()));
    } finally {
        RequestContext.getCurrentContext().unset();
    }
}

按顺序执行了 preRoute route postRoute 等规则路由

这些执行都给了 zuulRunner ---> FilterProcessor

processor处理的逻辑代码如下

public Object runFilters(String sType) throws Throwable {
    if (RequestContext.getCurrentContext().debugRouting()) {
        Debug.addRoutingDebug("Invoking {" + sType + "} type filters");
    }
    boolean bResult = false;
    List<ZuulFilter> list = FilterLoader.getInstance().getFiltersByType(sType);
    if (list != null) {
        for (int i = 0; i < list.size(); i++) {
            ZuulFilter zuulFilter = list.get(i);
            Object result = processZuulFilter(zuulFilter);
            if (result != null && result instanceof Boolean) {
                bResult |= ((Boolean) result);
            }
        }
    }
    return bResult;
}

List<ZuulFilter> list = FilterLoader.getInstance().getFiltersByType(sType);  这句可以获取所有的Filter类型

是从 FilterRegistry. filters 属性中来的

FilterRegistry 中的filters 是启动的时候org.springframework.cloud.netflix.zuul.ZuulFilterInitializer#contextInitialized 注入的

ZuulFilterInitializer又是从下面的代码中获取的

org.springframework.cloud.netflix.zuul.ZuulServerAutoConfiguration.ZuulFilterConfiguration#zuulFilterInitializer 代码如下

@Configuration
protected static class ZuulFilterConfiguration {

   @Autowired
   private Map<String, ZuulFilter> filters;

   @Bean
   public ZuulFilterInitializer zuulFilterInitializer(
         CounterFactory counterFactory, TracerFactory tracerFactory) {
      FilterLoader filterLoader = FilterLoader.getInstance();
      FilterRegistry filterRegistry = FilterRegistry.instance();
      return new ZuulFilterInitializer(this.filters, counterFactory, tracerFactory, filterLoader, filterRegistry);
   }

}

filters 聚合 ZuulServerAutoConfiguration ZuulProxyAutoConfiguration 这两个自动配置类的 filter实例

这里比较重要的