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[Spring cloud 一步步实现广告系统] 3. 网关路由

Zuul(Router and Filter)

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[Spring cloud 一步步实现广告系统] 3. 网关路由
作用
  1. 认证,鉴权(Authentication/Security)
  2. 预判(Insights)
  3. 压力测试(Stress Testing)
  4. 灰度/金丝雀测试(Canary Testing)
  5. 动态路由(Dynamic Routing)
  6. 服务迁移(Service Migration)
  7. 降低负载(Load Shedding)
  8. 静态响应处理(Static Response handling)
  9. 主动/主动交换管理(Active/Active traffic management)

关键配置:

The configuration property

zuul.host.maxTotalConnections

and

zuul.host.maxPerRouteConnections

, which default to 200 and 20 respectively.
创建

mscx-ad-zuul

三步曲创建法:

添加依赖

<dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
    </dependencies>           

加注解

@SpringCloudApplication
@EnableZuulProxy //启用网关
public class GatewayApplication {
    public static void main(String[] args) {
        SpringApplication.run(GatewayApplication.class, args);
    }
}           

改配置

spring:
  application:
    name: ad-gateway-zuul
server:
  port: 1111
eureka:
  client:
    service-url:
      defaultZone: http://server1:7777/eureka/,http://server2:8888/eureka/,http://server3:9999/eureka/
  instance:
    hostname: ad-gateway-zuul
zuul:
  ignored-services: '*' # 过滤所有请求,除了下面routes中声明过的服务
  routes:
    sponsor: #在路由中自定义服务路由名称
      path: /ad-sponsor/**
      serviceId: mscx-ad-sponsor #微服务name
      strip-prefix: false
    search: #在路由中自定义服务路由名称
      path: /ad-search/**
      serviceId: mscx-ad-search #微服务name
      strip-prefix: false
  prefix: /gateway/api
  strip-prefix: false #不对 prefix: /gateway/api 设置的路径进行截取,默认转发会截取掉配置的前缀
           

过滤器编写

我们来编写一个记录请求时间周期的过滤器,根据Filter的三种类型:

Pre filters

,

routing filters

Post filters

,我们需要定义2个filter,用来记录开始和结束时间,很明显,我们需要实现

Pre

&

Post

2个过滤器。

@Slf4j
@Component
public class PreRequestFilter extends ZuulFilter {
    @Override
    public String filterType() {
        // pre filter
        return FilterConstants.PRE_TYPE;
    }

    @Override
    public int filterOrder() {
        return 0;
    }

    @Override
    public boolean shouldFilter() {
        return true;
    }

    @Override
    public Object run() throws ZuulException {
        //获取当前请求的请求上下文
        RequestContext requestContext = RequestContext.getCurrentContext();
        //记录请求进入时间
        requestContext.set("api_request_time", System.currentTimeMillis());
        return null;
    }
}

---
  
@Slf4j
@Component
public class AccessLogFilter extends ZuulFilter {

    @Override
    public String filterType() {
        return FilterConstants.POST_TYPE;
    }

    @Override
    public int filterOrder() {
        //需要最后一个执行的filter
        return FilterConstants.SEND_RESPONSE_FILTER_ORDER - 1;
    }

    @Override
    public boolean shouldFilter() {
        return true;
    }

    @Override
    public Object run() throws ZuulException {
        RequestContext requestContext = RequestContext.getCurrentContext();
        HttpServletRequest request = requestContext.getRequest();
        log.info("Request \"{}\" spent : {} seconds.", request.getRequestURI(),
                (System.currentTimeMillis() - Long.valueOf(requestContext.get("api_request_time").toString())) / 1000);
        return null;
    }
}           

Gateway

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