springboot~zuul实现网关

网关在微服务里的角色

在微服务架构体系里，网关是非常重要的一个环节，它主要实现了一些功能的统一处理，包括了：

1. 统一授权
2. 统一异常处理
3. 路由导向
4. 跨域处理
5. 限流

实践一下

1 添加依赖

dependencies {
    implementation('org.springframework.cloud:spring-cloud-starter-netflix-eureka-client')
    implementation('org.springframework.cloud:spring-cloud-starter-netflix-zuul')
    testimplementation('org.springframework.boot:spring-boot-starter-test')
    implementation('com.marcosbarbero.cloud:spring-cloud-zuul-ratelimit:1.3.2.release')
}

2 添加yml

server:
  port: 8300
spring:
  application:
    name: microservice-gateway-zuul
eureka:
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultzone: http://localhost:6761/eureka
  instance:
    ip-address: true

zuul:
 routes:
    users:
       path: /lind/** #以lind开头的路径被重定向到lind服务
       serviceid: lind
 add-host-header: true #显示真实的http头
 retryable: false #关闭hystrix的重试功能
 ratelimit:
    enabled: true
   #  repository: redis
    behind-proxy: true
    policies:
       users:
         limit: 5 #限流，每分钟请求5次
         refresh-interval: 60
         type:
           - user
           - origin
           - url
         #       url类型的限流就是通过请求路径区分
         #       origin是通过客户端ip地址区分
         #       user是通过授权用户进行区分，也包括匿名用户

3 添加实现代码
http拦截器，获取用户id，为子服务进行传递

public class prerequestlogfilter extends zuulfilter {
  private static final logger logger = loggerfactory.getlogger(prerequestlogfilter.class);
  private final ratelimiter ratelimiter = ratelimiter.create(1000.0);

  @override
  public object run() {

    try {
      requestcontext currentcontext = requestcontext.getcurrentcontext();
      httpservletresponse response = currentcontext.getresponse();
      httpservletrequest reqeust = currentcontext.getrequest();

      currentcontext.addzuulrequestheader("userid","123");//向子系统http头写数据
      currentcontext.addzuulrequestheader("username","test");

      prerequestlogfilter.logger.info(
          string.format("send %s request to %s",
              reqeust.getmethod(),
              reqeust.getrequesturl().tostring()));

      if (!ratelimiter.tryacquire()) {
        httpstatus httpstatus = httpstatus.too_many_requests;
        response.setcontenttype(mediatype.text_plain_value);
        response.setstatus(httpstatus.value());
        response.getwriter().append(httpstatus.getreasonphrase());
        currentcontext.setsendzuulresponse(false);
        throw new zuulexception(
            httpstatus.getreasonphrase(),
            httpstatus.value(),
            httpstatus.getreasonphrase()
        );
      }
    } catch (java.lang.exception e) {
      reflectionutils.rethrowruntimeexception(e);
    }
    return null;

  }

  @override
  public boolean shouldfilter() {

    // 判断是否需要过滤
    return true;

  }


  @override

  public string filtertype() {

    return filterconstants.pre_type;

  }


  @override

  public int filterorder() {

    return ordered.highest_precedence;

  }


}

在主程中注入这个过滤器

  @bean
  public prerequestlogfilter prerequestlogfilter() {
    return new prerequestlogfilter();
  }

4 使用它
在url上通过localhost:8300/users/home 将进行lind服务里的home控制器下，并在http头上写入了userid和username这个键值对！