Spring Cloud使用Zuul构建网关

不使用网关会存在的问题？

客户端多次请求不同的微服务，增加了客户端的复杂性。存在跨域问题。认证复杂，每个服务都需要独立认证。难以重构，随着项目的迭代，可能需要重写划分微服务。某些微服务可能使用了防火墙/浏览器不友好的协议，直接访问有一定困难。

什么是微服务网关？

微服务网关介于客户端与服务器端之间，所有的外部请求都会讲过微服务网关。 使用微服务网关的优点：

客户端只需和网关交互，而无需调用特定的微服务接口。易于监控易于认证减少了客户端与各个微服务之间的交互次数

什么是Zuul？

Zuul是Netflix开源的微服务网关，可以和Eureka、Ribbon、Hystrix等组件配合使用。其核心似乎一系列过滤器，可完成如下功能。

身份认证与安全：识别每个资源的验证要求，拒绝不符合要求的请求。审查与监控：在边缘位置追踪有意义的数据和统计结果，从而带来精确的生产视图。动态路由：动态地将请求路由到不同地后端集群。压力测试：逐渐增加指向集群的流量，以了解性能。负载分配：为每一种负载类型分配对应地容量，并启用超出限定值的请求。静态响应处理：在边缘位置直接建立部分响应，从而避免其转发到内部集群。多区域弹性：跨越AWS Region进行请求路由，旨在实现ELB(Elastic Load Balancing)使用的多样化，已经让系统的边缘更贴近系统的使用者。

上述内容截取自书籍 《Spring Cloud与Docker微服务架构与实战》

Spring Cloud使用Zuul

(1)Eureka Server

pom.xml

<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.5.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.dfyang</groupId> <artifactId>eureka-server</artifactId> <version>0.0.1-SNAPSHOT</version> <name>eureka-server</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId> </dependency> </dependencies> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>Greenwich.RELEASE</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>

application.xml

server: port: 8761 spring: application: name: eureka-server eureka: client: #是否将自己注册到Eureka Server，由于当前应用为Eureka Service，故为false register-with-eureka: false #是否从Eureka Server获取注册信息，由于是单点，所以为false fetch-registry: false #与Eureka Server交互的地址 serviceUrl: defaultZone: http://localhost:8761/eureka/

启动类

package com.dfyang; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer; @SpringBootApplication @EnableEurekaServer public class EurekaServerApplication { public static void main(String[] args) { SpringApplication.run(EurekaServerApplication.class, args); } }

启动项目，访问localhost:8761成功跳转页面即编写成功

(2)服务投递者

pom.xml

<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.5.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.dfyang</groupId> <artifactId>service-producer</artifactId> <version>0.0.1-SNAPSHOT</version> <name>service-producer</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId> </dependency> </dependencies> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>Greenwich.RELEASE</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>

application.xml

server: port: 8080 spring: application: name: service-producer eureka: client: serviceUrl: defaultZone: http://localhost:8761/eureka/

启动类

package com.dfyang; import com.netflix.hystrix.contrib.metrics.eventstream.HystrixMetricsStreamServlet; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.boot.web.servlet.ServletRegistrationBean; import org.springframework.cloud.netflix.eureka.EnableEurekaClient; import org.springframework.cloud.netflix.hystrix.EnableHystrix; import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard; import org.springframework.cloud.netflix.turbine.EnableTurbine; import org.springframework.context.annotation.Bean; @SpringBootApplication @EnableEurekaClient public class ServiceProducerApplication { public static void main(String[] args) { SpringApplication.run(ServiceProducerApplication.class, args); } }

提供的服务

package com.dfyang.serviceProducer.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @RestController public class ProducerController { @RequestMapping("/serviceA") public String serviceA() { return "服务A"; } @RequestMapping("/serviceB") public String serviceB() { return "服务B"; } }

启动项目，访问localhost:8761，出现如下即成功

(3)服务消费者

pom.xml

<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.5.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.dfyang</groupId> <artifactId>service-consumer</artifactId> <version>0.0.1-SNAPSHOT</version> <name>service-consumer</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> </dependency> </dependencies> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>Greenwich.RELEASE</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>

application.yml

server: port: 8082 spring: application: name: service-consumer eureka: client: service-url: defaultZone: http://localhost:8761/eureka/

启动类

package com.dfyang; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.client.discovery.EnableDiscoveryClient; import org.springframework.cloud.openfeign.EnableFeignClients; @SpringBootApplication @EnableEurekaClient @EnableFeignClients public class ServiceConsumerApplication { public static void main(String[] args) { SpringApplication.run(ServiceConsumerApplication.class, args); } }

使用Fegin远程调用服务

package com.dfyang.serviceConsumer.controller; import org.springframework.cloud.openfeign.FeignClient; import org.springframework.stereotype.Service; import org.springframework.web.bind.annotation.GetMapping; @Service @FeignClient(name = "service-producer") public interface ProducerService { @GetMapping("/serviceA") public String serviceA(); @GetMapping("/serviceB") public String serviceB(); }

消费服务

package com.dfyang.serviceConsumer.controller; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RestController; @RestController public class ConsumerController { @Autowired private ProducerService producerService; @GetMapping("/consumeA") public String consumeA() { return producerService.serviceA(); } @GetMapping("/consumeB") public String consumeB() { return producerService.serviceB(); } }

启动项目，输入localhost:8761 访问 localhost:8082/consumeA 和 localhost:8082/consumeB 成功！

(4)Zuul网关

pom.xml

<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.5.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.dfyang</groupId> <artifactId>eureka-zuul</artifactId> <version>0.0.1-SNAPSHOT</version> <name>eureka-zuul</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-zuul</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> </dependencies> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>Greenwich.RELEASE</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>

application.yml

server: port: 8084 spring: application: name: eureka-zuul eureka: client: service-url: defaultZone: http://localhost:8761/eureka/ #为应用程序显示详细的健康指标，并未actuator开启所有的endpoint management: endpoints: web: exposure: include: "*" endpoint: health: show-details: always

启动类

package com.dfyang; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.zuul.EnableZuulProxy; @SpringBootApplication @EnableZuulProxy public class EurekaZuulApplication { public static void main(String[] args) { SpringApplication.run(EurekaZuulApplication.class, args); } }

启动项目，访问localhost:8761 输入localhost:8084/service-consumer/consumeA 和 localhost:8084/service-consumer/consumeB 将出现与访问 localhost:8082/consumeA 和 localhost:8082/consumeB相同的结果

也就是我们所有的请求都交给了Zuul，再由Zuul将请求转发到微服务。 访问 http://localhost:8084/actuator/routes 从上面可以看出 请求的格式为： http://zuul_host:zuul_port/微服务在Eureka的serviceId/** 如果我们需要将 [微服务在Eureka的serviceId] 替换为别的，只需要添加如下

zuul: routes: service-producer: /producer/** service-consumer: /consumer/**

访问ocalhost:8084/consumer/consumeA 和 localhost:8084/consumer/consumeB（但之前的仍然可以访问） 可以添加忽略的服务

zuul: routes: service-producer: /producer/** service-consumer: /consumer/** ignored-services: service-producer,service-consumer

再次访问，成功！