spring cloud 2.x版本 Gateway路由网关教程

前言

本文采用Spring cloud本文为2.1.8RELEASE，version=Greenwich.SR3

本文基于前两篇文章eureka-server、eureka-client、eureka-ribbon和eureka-feign的实现。
参考

• eureka-server
• eureka-client
• eureka-ribbon
• eureka-feign

概念

Spring Cloud Gateway是Spring Cloud的一个新项目，该项目是基于Spring5.0，Sprint Boot2.0和Project Reactor等技术开发的网关，它的目的是在微服务架构中提供一种简单有效的统一api路由管理方式。
Spring Cloud Gateway目标是要替代Netflix Zuul，其不仅提供统一的路由管理方式，还提供一套基于Fliter链的方式的网关其他功能，比如：限流、埋点、安全监控等。

名称术语

• Route(路由)：网关的基本模块，它有一个id、一个目标uri、一组断言和一组过滤器组成，如果断言为真，则路由匹配。
• Predicate(断言)：是一个java8的Predicate。输入类型是一个ServerWebExchange。可以使用它来匹配来自HTTP请求的内容。
• Filter(过滤器)：是org.springframework.cloud.gateway.filter.GatewayFilter的实例，可以使用它来修改请求和响应。

流程

image

客户端向Spring Cloud Gateway发出请求。如果Gateway Handler映射确定请求与路由匹配，则将其发送到Gateway Web Handler。Gateway Web Handler通过特定于请求的筛选器链发送请求。筛选器由虚线分隔的原因是，筛选器可以在发送代理请求之前或之后执行逻辑。执行所有“pre”筛选逻辑，然后发出代理请求。在发出代理请求后，执行“POST”筛选逻辑。

创建Zuul工程

1.1 创建sping boot工程：spring-gateway

1.2 添加pom.xml相关依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-webflux</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>

1.3 application.yml添加配置信息

server:
  port: 8100
spring:
  application:
    name: spring-gateway
  cloud:
      gateway:
        discovery:
          locator:
            enabled: true
eureka:
  instance:
    hostname: eureka1.server.com
    lease-renewal-interval-in-seconds: 5
    lease-expiration-duration-in-seconds: 10
  client:
    service-url:
      defaultZone: http://eureka1.server.com:8701/eureka/,http://eureka2.server.com:8702/eureka/,http://eureka3.server.com:8703/eureka/

Spring.cloud.gateway.discovery.locator.enabled:true 这里先简单使用了默认的创建路由规则,自动根据serviceid创建路由的功能

1.4 启动类SpringGatewayApplication说明

前几片文章中都在对应的启动类中增加了@EnableEurekaClient或@EnableDiscoveryClient注解，今天看文档突然发现，不用加@Enable*注解也可以自动添加到注册中心，是因为在Spring Cloud Edgware版本之后，只要加上相关的依赖，并进行相应的配置就可以将服务自动注册到服务发现组件上。

1.5 启动相关服务

按顺序启动eureka-server、eureka-client、eureka-ribbon、spring-gateway服务。
打开浏览器，先去eureka-server服务中心看一下服务是否正常启动，如下如：

image
截图中红框代表所有服务已经正常启动。
然后新打来浏览器输入：http://localhost:8100/SPRING-GATEWAY/EUREKA-RIBBON/sayHello，显示如下： image

因为我们才用的是自动配置路由，所有这里url上的服务名称要全部大写，就是和服务注册中心保存一致。
这里我可以看一下spring-gate的启动日志，自动路由名称全部是大写。（个人觉得这里设计的不是很好）。

2019-10-12 16:40:35.870  INFO 97725 --- [ctor-http-nio-2] c.netflix.config.ChainedDynamicProperty  : Flipping property: SPRING-GATEWAY.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2019-10-12 16:40:35.890  INFO 97725 --- [ctor-http-nio-2] c.n.u.concurrent.ShutdownEnabledTimer    : Shutdown hook installed for: NFLoadBalancer-PingTimer-SPRING-GATEWAY
2019-10-12 16:40:35.890  INFO 97725 --- [ctor-http-nio-2] c.netflix.loadbalancer.BaseLoadBalancer  : Client: SPRING-GATEWAY instantiated a LoadBalancer: DynamicServerListLoadBalancer:{NFLoadBalancer:name=SPRING-GATEWAY,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null
2019-10-12 16:40:35.895  INFO 97725 --- [ctor-http-nio-2] c.n.l.DynamicServerListLoadBalancer      : Using serverListUpdater PollingServerListUpdater
2019-10-12 16:40:35.910  INFO 97725 --- [ctor-http-nio-2] c.netflix.config.ChainedDynamicProperty  : Flipping property: SPRING-GATEWAY.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2019-10-12 16:40:35.911  INFO 97725 --- [ctor-http-nio-2] c.n.l.DynamicServerListLoadBalancer      : DynamicServerListLoadBalancer for client SPRING-GATEWAY initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=SPRING-GATEWAY,current list of Servers=[eureka1.server.com:8100],Load balancer stats=Zone stats: {defaultzone=[Zone:defaultzone;   Instance count:1;   Active connections count: 0;    Circuit breaker tripped count: 0;   Active connections per server: 0.0;]
},Server stats: [[Server:eureka1.server.com:8100;   Zone:defaultZone;   Total Requests:0;   Successive connection failure:0;    Total blackout seconds:0;   Last connection made:Thu Jan 01 08:00:00 CST 1970;  First connection made: Thu Jan 01 08:00:00 CST 1970;    Active Connections:0;   total failure count in last (1000) msecs:0; average resp time:0.0;  90 percentile resp time:0.0;    95 percentile resp time:0.0;    min resp time:0.0;  max resp time:0.0;  stddev resp time:0.0]
]}ServerList:org.springframework.cloud.netflix.ribbon.eureka.DomainExtractingServerList@3b80e99c
2019-10-12 16:40:36.008  INFO 97725 --- [tor-http-nio-10] c.netflix.config.ChainedDynamicProperty  : Flipping property: EUREKA-RIBBON.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2019-10-12 16:40:36.009  INFO 97725 --- [tor-http-nio-10] c.n.u.concurrent.ShutdownEnabledTimer    : Shutdown hook installed for: NFLoadBalancer-PingTimer-EUREKA-RIBBON
2019-10-12 16:40:36.010  INFO 97725 --- [tor-http-nio-10] c.netflix.loadbalancer.BaseLoadBalancer  : Client: EUREKA-RIBBON instantiated a LoadBalancer: DynamicServerListLoadBalancer:{NFLoadBalancer:name=EUREKA-RIBBON,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null
2019-10-12 16:40:36.011  INFO 97725 --- [tor-http-nio-10] c.n.l.DynamicServerListLoadBalancer      : Using serverListUpdater PollingServerListUpdater
2019-10-12 16:40:36.012  INFO 97725 --- [tor-http-nio-10] c.netflix.config.ChainedDynamicProperty  : Flipping property: EUREKA-RIBBON.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2019-10-12 16:40:36.012  INFO 97725 --- [tor-http-nio-10] c.n.l.DynamicServerListLoadBalancer      : DynamicServerListLoadBalancer for client EUREKA-RIBBON initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=EUREKA-RIBBON,current list of Servers=[eureka1.server.com:8901],Load balancer stats=Zone stats: {defaultzone=[Zone:defaultzone; Instance count:1;   Active connections count: 0;    Circuit breaker tripped count: 0;   Active connections per server: 0.0;]
},Server stats: [[Server:eureka1.server.com:8901;   Zone:defaultZone;   Total Requests:0;   Successive connection failure:0;    Total blackout seconds:0;   Last connection made:Thu Jan 01 08:00:00 CST 1970;  First connection made: Thu Jan 01 08:00:00 CST 1970;    Active Connections:0;   total failure count in last (1000) msecs:0; average resp time:0.0;  90 percentile resp time:0.0;    95 percentile resp time:0.0;    min resp time:0.0;  max resp time:0.0;  stddev resp time:0.0]
]}ServerList:org.springframework.cloud.netflix.ribbon.eureka.DomainExtractingServerList@19148ab

同样的方式我可以请求eureka-feign，结果如下：

image

至此基于服务发现的默认路由规则就搭建完成。

1.6 自定义路由规则

1.6.1 修改application.yml配置

server:
  port: 8100
spring:
  application:
    name: spring-gateway
  cloud:
      gateway:
#        discovery:
#          locator:
#            enabled: true # 开启通过服务中心的自动根据 serviceId 创建路由的功能
        routes:
          - id: ribbon-route
            uri: lb://EUREKA-RIBBON
            order: 0
            predicates:
              - Path=/ribbon/**
            filters:
              - StripPrefix=1 #去掉前缀，具体实现参考StripPrefixGatewayFilterFactory
              - AddResponseHeader=X-Response-Default-Foo, Default-Bar
          - id: feign-route
            uri: lb://EUREKA-FEIGN
            order: 0
            predicates:
              - Path=/feign/**
            filters:
              - StripPrefix=1
              - AddResponseHeader=X-Response-Default-Foo, Default-Bar

eureka:
  instance:
    hostname: eureka1.server.com
    lease-renewal-interval-in-seconds: 5
    lease-expiration-duration-in-seconds: 10
  client:
    service-url:
      defaultZone: http://eureka1.server.com:8701/eureka/,http://eureka2.server.com:8702/eureka/,http://eureka3.server.com:8703/eureka/

StripPrefix: 接受一个非负整数，对应的具体实现是StripPrefixGatewayFilterFactory，做用是去掉前缀，整数对应层数。在本例中访问的/ribbon/sayHello，网关服务向后转发请求的时候会去掉/ribbon，eureka-ribbon收到的请求是：/sayHello。eureka-feign同理。

1.6.2 启动服务

访问http://localhost:8100/ribbon/sayHello和http://localhost:8100/feign/feign/sayHello，如图下图显示：

• ribbon:

image

• feign:

image

1.6.3 自定义Configuration

Spring Cloud Gateway同时支持java的流式api的路由定义，可以和application.yml配合使用。

package spring.cloud.demo.spring.gateway.config;

import org.springframework.cloud.gateway.route.RouteLocator;
import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class RoutesConfig {

    @Bean
    public RouteLocator routeLocator(RouteLocatorBuilder routeLocatorBuilder){
        return routeLocatorBuilder.routes().route(r -> r.path("/ribbon/**")
                .filters(f -> f.stripPrefix(1)
                        .addRequestHeader("X-Response-Default-Foo", "Default-Bar"))
                .uri("lb://EUREKA-RIBBON")
                .order(0)
                .id("ribbon-route")
        ).build();
    }
}

总结

本文简单实现了Spring Cloud Gateway的默认自动路由和自定义路由的网关服务。后面会继续更新Spring Cloud Gateway的其他功能，敬请期待！

代码地址

gitHub地址

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<center><font color=red>《Srping Cloud 2.X小白教程》目录</font></center>

• spring cloud 2.x版本 Eureka Server服务注册中心教程
• spring cloud 2.x版本 Eureka Client服务提供者教程
• spring cloud 2.x版本 Ribbon服务发现教程(内含集成Hystrix熔断机制)
• spring cloud 2.x版本 Feign服务发现教程(内含集成Hystrix熔断机制)
• spring cloud 2.x版本 Zuul路由网关教程
• spring cloud 2.x版本 config分布式配置中心教程
• spring cloud 2.x版本 Hystrix Dashboard断路器教程
• spring cloud 2.x版本 Gateway路由网关教程

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