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:

* 统一授权
* 统一异常处理
* 路由导向
* 跨域处理
* 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!