zuul网关

zuul网关

• • zuul自定义过滤器
  • hystrix和ribbon时间
  • RibbonAutoConfiguration自动配置
  • FeignAutoConfiguration自动配置
  • RibbonEurekaAutoConfiguration
  • SendErrorFilter过滤器
  • @EnableZuulServer
  • • HasFeatures
  • @EnableZuulProxy

zuul自定义过滤器

1. 继承ZuulFilter类，实现其方法filterType()、filterOrder()、shouldFilter()、run()
   1. filterType()表示过滤器的类型：pre-前置过滤器，用于请求处理前；route-路由过滤器，用于路由请求；post-后置过滤器，用于响应请求；error-错误过滤器，用于处理错误情况。
   2. filterOrder()表示过滤器的执行顺序，较小意味着先执行
   3. shouldFilter()表示是否执行过滤器的逻辑，可以编写逻辑确定是否执行过滤器
   4. run()，过滤器的实际执行逻辑

import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;

public class CustomFilter extends ZuulFilter {

    @Override
    public String filterType() {
        return "pre"; // 前置过滤器
    }

    @Override
    public int filterOrder() {
        return 1; // 执行顺序，数字越小越早执行
    }

    @Override
    public boolean shouldFilter() {
        return true; // 在该方法中可以定义过滤器是否执行的逻辑
    }

    @Override
    public Object run() {
        // 获取请求的信息
        RequestContext ctx = RequestContext.getCurrentContext();
        HttpServletRequest request = ctx.getRequest();
        String uri = request.getRequestURI();
        // 获取请求信息、响应信息等
        // 对请求或响应进行处理
        if(auth(ctd)){
			ctx.setSendZuulResponse(false); // 不将请求路由到后端服务
            ctx.setResponseStatusCode("401"); 
            ctx.setResponseBody("Access Denied"); // 设置响应内容
            ctx.set("responseFiltered", true); // 标记该请求已被过滤
        }
        return null;
    }
}

hystrix和ribbon时间

Ribbon超时时间

Hystrix超时时间

配置文件

调用过程

RibbonAutoConfiguration自动配置

// 注入属性
@Autowired(required = false)
private List<RibbonClientSpecification> configurations = new ArrayList<>();

FeignAutoConfiguration自动配置

@Bean
public FeignContext feignContext() {
	FeignContext context = new FeignContext();
	context.setConfigurations(this.configurations);
	return context;
}

RibbonEurekaAutoConfiguration

SendErrorFilter过滤器

sendErrorFilter.ran请求上下为true则不执行这个默认过滤器

public class SendErrorFilter extends ZuulFilter {

	private static final Log log = LogFactory.getLog(SendErrorFilter.class);
	protected static final String SEND_ERROR_FILTER_RAN = "sendErrorFilter.ran";

	@Value("${error.path:/error}")
	private String errorPath;

	@Override
	public String filterType() {
		return ERROR_TYPE;
	}

	@Override
	public int filterOrder() {
		return SEND_ERROR_FILTER_ORDER;
	}

	@Override
	public boolean shouldFilter() {
		RequestContext ctx = RequestContext.getCurrentContext();
		// only forward to errorPath if it hasn't been forwarded to already
		return ctx.getThrowable() != null
				&& !ctx.getBoolean(SEND_ERROR_FILTER_RAN, false);
	}

	@Override
	public Object run() {
		try {
			RequestContext ctx = RequestContext.getCurrentContext();
            // 获取异常信息
			ExceptionHolder exception = findZuulException(ctx.getThrowable());
			HttpServletRequest request = ctx.getRequest();
			
			request.setAttribute("javax.servlet.error.status_code", exception.getStatusCode());
			// 打印什么原因导致的异常异常的信息
			log.warn("Error during filtering", exception.getThrowable());
			request.setAttribute("javax.servlet.error.exception", exception.getThrowable());

			if (StringUtils.hasText(exception.getErrorCause())) {
				request.setAttribute("javax.servlet.error.message", exception.getErrorCause());
			}

			RequestDispatcher dispatcher = request.getRequestDispatcher(
					this.errorPath);
			if (dispatcher != null) {
				ctx.set(SEND_ERROR_FILTER_RAN, true);
				if (!ctx.getResponse().isCommitted()) {
					ctx.setResponseStatusCode(exception.getStatusCode());
					dispatcher.forward(request, ctx.getResponse());
				}
			}
		}
		catch (Exception ex) {
			ReflectionUtils.rethrowRuntimeException(ex);
		}
		return null;
	}

	protected ExceptionHolder findZuulException(Throwable throwable) {
		if (throwable.getCause() instanceof ZuulRuntimeException) {
			Throwable cause = null;
			if (throwable.getCause().getCause() != null) {
				cause = throwable.getCause().getCause().getCause();
			}
			if (cause instanceof ClientException && cause.getCause() != null
					&& cause.getCause().getCause() instanceof SocketTimeoutException) {

				ZuulException zuulException = new ZuulException("", 504,
						ZuulException.class.getName() + ": Hystrix Readed time out");
				return new ZuulExceptionHolder(zuulException);
			}
			// this was a failure initiated by one of the local filters
			if(throwable.getCause().getCause() instanceof ZuulException) {
				return new ZuulExceptionHolder((ZuulException) throwable.getCause().getCause());
			}
		}
		
		if (throwable.getCause() instanceof ZuulException) {
			// wrapped zuul exception
			return  new ZuulExceptionHolder((ZuulException) throwable.getCause());
		}

		if (throwable instanceof ZuulException) {
			// exception thrown by zuul lifecycle
			return new ZuulExceptionHolder((ZuulException) throwable);
		}

		// fallback
		return new DefaultExceptionHolder(throwable);
	}

	protected interface ExceptionHolder {
		Throwable getThrowable();

	    default int getStatusCode() {
	    	return HttpStatus.INTERNAL_SERVER_ERROR.value();
		}

	    default String getErrorCause() {
	    	return null;
		}
	}

	protected static class DefaultExceptionHolder implements ExceptionHolder {
		private final Throwable throwable;

		public DefaultExceptionHolder(Throwable throwable) {
			this.throwable = throwable;
		}

		@Override
		public Throwable getThrowable() {
			return this.throwable;
		}
	}

	protected static class ZuulExceptionHolder implements ExceptionHolder {
		private final ZuulException exception;

		public ZuulExceptionHolder(ZuulException exception) {
			this.exception = exception;
		}

		@Override
		public Throwable getThrowable() {
			return this.exception;
		}

		@Override
		public int getStatusCode() {
			return this.exception.nStatusCode;
		}

		@Override
		public String getErrorCause() {
			return this.exception.errorCause;
		}
	}

	public void setErrorPath(String errorPath) {
		this.errorPath = errorPath;
	}

}

@EnableZuulServer

ZuulServerAutoConfiguration自动注入的类

将应用程序设置为没有任何内置反向代理特性的通用Zuul服务器。到Zuul服务器的路由可以通过ZuulProperties配置(默认情况下没有)

HasFeatures

@EnableZuulProxy

设置一个Zuul服务器端点，并在其中安装一些反向代理过滤器，这样它就可以将请求转发到后端服务器。后端可以通过配置手工注册，也可以通过DiscoveryClient注册。

1. ServiceRouteMapper
2. DiscoveryClientRouteLocator
3. HasFeatures
4. HttpClientConfiguration(Import)
   1. ApacheHttpClientConnectionManagerFactory
   2. HttpClientBuilder
   3. ApacheHttpClientFactory
5. RibbonCommandFactoryConfiguration.HttpClientRibbonConfiguration.class(Import)
   1. RibbonCommandFactory
6. PreDecorationFilter
7. RibbonRoutingFilter
8. SimpleHostRoutingFilter