Spring Cloud(八)《服务网关路由 Zuul1》

2019/11/08

前言介绍

为什么会有路由层?因为在微服务架构设计中,往往并不会直接将服务暴漏给调用端,而是通过调用路由层进行业务隔离,以达到不同的业务调用对应的服务模块。

Spring Cloud Zuul

Spring Cloud Zuul 路由是微服务架构的不可或缺的一部分,提供动态路由、监控、弹性、安全等的边缘服务。Zuul 是 Netflix 出品的一个基于 JVM 路由和服务端的负载均衡器。 微信公众号:bugstack虫洞栈 & Spring Cloud Zuul

环境准备

  1. jdk 1.8、idea2018、Maven3
  2. Spring Boot 2.0.6.RELEASE
  3. Spring Cloud Finchley.SR2

代码示例

itstack-demo-springcloud-08
├── itstack-demo-springcloud-eureka-client
   └── src
       └── main
           ├── java
              └── org.itstack.demo
                   ├── web
                      └── EurekaClientController.java
                   └── EurekaClientApplication.java
           └── resources   
               └── application.yml
├── itstack-demo-springcloud-eureka-server
   └── src
       └── main
           ├── java
              └── org.itstack.demo
                   └── EurekaServerApplication.java
           └── resources   
               └── application.yml
├── itstack-demo-springcloud-hystrix-feign
   └── src
       └── main
           ├── java
              └── org.itstack.demo
                   ├── service
                      ├── hystrix
                         └── FeignServiceHystrix.java
                      └── FeignService.java
                   ├── web
                      └── FeignController.java
                   └── FeignApplication.java
           └── resources   
               └── application.yml
├── itstack-demo-springcloud-hystrix-ribbon
   └── src
       └── main
           ├── java
              └── org.itstack.demo
                   ├── service
                      └── RibbonService.java
                   ├── web
                      └── RibbonController.java      
                   └── RibbonApplication.java
           └── resources   
               └── application.yml
└── itstack-demo-springcloud-zuul
    └── src
        └── main
            ├── java
               └── org.itstack.demo   
                    └── ZuulApplication.java
            └── resources   
                └── application.yml

itstack-demo-springcloud-eureka-client | 服务提供方

提供一个查询用户信息的简单方法,在配置文件中通过修改端口启动2次,模拟双实例应用,为调用方负载做准备。

web/EurekaClientController.java & 注意@EnableEurekaClient用于向注册中心提供服务 ```java /**

  • 微信公众号:bugstack虫洞栈 沉淀、分享、成长,专注于原创专题案例
  • 论坛:http://bugstack.cn
  • Create by 付政委 on @2019 */ @EnableEurekaClient @RestController public class EurekaClientController {
@Value("${server.port}")
private int port;

@RequestMapping(path = "/api/queryUserInfo", method = RequestMethod.GET)
public String queryUserInfo(@RequestParam String userId) {
    return "Hi 微信公众号:bugstack虫洞栈 | " + userId + " >: from eureka client port: " + port;
}

}


>EurekaClientApplication.java & 服务启动类
```java
/**
 * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例
 * 论坛:http://bugstack.cn
 * Create by 付政委 on @2019
 */
@SpringBootApplication
public class EurekaClientApplication {

    public static void main(String[] args) {
        SpringApplication.run(EurekaClientApplication.class, args);
    }

}

pom.xml & 配置文件指向注册中心 ```java server: port: 8001

spring: application: name: itstack-demo-springcloud-eureka-client

eureka: client: serviceUrl: defaultZone: http://localhost:7397/eureka/


### itstack-demo-springcloud-eureka-server | 单个服务注册中心
服务注册中心用于承载接口提供方向上注册,同时正在调用方链接后可以获取指定应用的服务实例。

>EurekaServerApplication.java & 通过注解@EnableEurekaServer启动服务注册与发现中心
```java
/**
 * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例
 * 论坛:http://bugstack.cn
 * Create by 付政委 on @2019
 */
@SpringBootApplication
@EnableEurekaServer
public class EurekaServerApplication {

    public static void main(String[] args) {
        SpringApplication.run( EurekaServerApplication.class, args );
    }

}

pom.xml & 服务注册中心 ```java server: port: 7397

eureka: instance: hostname: localhost client: registerWithEureka: false fetchRegistry: false serviceUrl: defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

spring: application: name: itstack-demo-springcloud-eureka-server


### itstack-demo-springcloud-feign | Feign服务调用方

Feign 是一个声明式的 Web Service 客户端,它的目的就是让 Web Service 调用更加简单。它整合了 Ribbon 和 Hystrix,从而让我们不再需要显式地使用这两个组件。Feign 还提供了 HTTP 请求的模板,通过编写简单的接口和插入注解,我们就可以定义好 HTTP 请求的参数、格式、地址等信息。接下来,Feign 会完全代理 HTTP 的请求,我们只需要像调用方法一样调用它就可以完成服务请求。

Feign 具有如下特性:

可插拔的注解支持,包括 Feign 注解和 JAX-RS 注解
支持可插拔的 HTTP 编码器和解码器
支持 Hystrix 和它的 Fallback
支持 Ribbon 的负载均衡
支持 HTTP 请求和响应的压缩

>service/FeignService.java | 注解方式调用,方便易用。@FeignClient会在调用时进行解析服务到具体的http://ip:port/

```java
/**
 * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例
 * 论坛:http://bugstack.cn
 * Create by 付政委 on @2019
 */
@FeignClient(value = "itstack-demo-springcloud-eureka-client", fallback = FeignServiceHystrix.class)
public interface FeignService {

    @RequestMapping(value = "/api/queryUserInfo", method = RequestMethod.GET)
    String queryUserInfo(@RequestParam String userId);

}
service/hystrix/FeignServiceHystrix.java 提供熔断服务,当发生异常时主动返回预定结果
/**
 * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例
 * 论坛:http://bugstack.cn
 * Create by 付政委 on @2019
 */
@Component
public class FeignServiceHystrix implements FeignService {

    @Override
    public String queryUserInfo(String userId) {
        return "queryUserInfo by userId:" + userId + " err!from feign hystrix";
    }
    
}
web/FeignController.java 使用接口提供服务 From Feign
/**
 * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例
 * 论坛:http://bugstack.cn
 * Create by 付政委 on @2019
 */
@RestController
public class FeignController {

    @Resource
    private FeignService ribbonService;

    @RequestMapping(path = "/api/queryUserInfo", method = RequestMethod.GET)
    public String queryUserInfo(@RequestParam String userId) {
        return ribbonService.queryUserInfo(userId) + " From Feign";
    }

}
FeignApplication.java 注解@EnableEurekaClient、@EnableFeignClients、@EnableDiscoveryClient获取调用注册中心服务
/**
 * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例
 * 论坛:http://bugstack.cn
 * Create by 付政委 on @2019
 */
@SpringBootApplication
@EnableEurekaClient
@EnableDiscoveryClient
@EnableFeignClients
@EnableHystrix
public class FeignApplication {

    public static void main(String[] args) {
        SpringApplication.run(FeignApplication.class, args);
    }

}
application.yml eureka服务配置,从注册中心获取可用服务。开启hystrix=true
server:
  port: 9001

spring:
  application:
    name: itstack-demo-springcloud-feign

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:7397/eureka/

feign.hystrix.enabled: true

itstack-demo-springcloud-ribbon | Ribbon服务调用方

Ribbon是一个基于 HTTP 和 TCP 的客户端负载均衡器。它可以通过在客户端中配置 ribbonServerList 来设置服务端列表去轮询访问以达到均衡负载的作用。

当 Ribbon 与 Eureka 联合使用时,ribbonServerList 会被 DiscoveryEnabledNIWSServerList 重写,扩展成从 Eureka 注册中心中获取服务实例列表。同时它也会用 NIWSDiscoveryPing 来取代 IPing,它将职责委托给 Eureka 来确定服务端是否已经启动。

service/RibbonService.java 接口式硬编码调用不太易于维护,因此也是比较少用的方式。hystrix实际通过getFallback()返回熔断结果
/**
 * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例
 * 论坛:http://bugstack.cn
 * Create by 付政委 on @2019
 */
@Service
public class RibbonService {

    @Autowired
    private RestTemplate restTemplate;

    @HystrixCommand(fallbackMethod = "queryUserInfoFallback")
    public String queryUserInfo(String userId) {
        return restTemplate.getForObject("http://ITSTACK-DEMO-SPRINGCLOUD-EUREKA-CLIENT/api/queryUserInfo?userId=" + userId, String.class);
    }

    /**
     * Specifies a method to process fallback logic.
     * A fallback method should be defined in the same class where is HystrixCommand.
     * Also a fallback method should have same signature to a method which was invoked as hystrix command.
     * for example:
     * <code>
     *      @HystrixCommand(fallbackMethod = "getByIdFallback")
     *      public String getById(String id) {...}
     *
     *      private String getByIdFallback(String id) {...}
     * </code>
     * Also a fallback method can be annotated with {@link HystrixCommand}
     * <p/>
     * default => see {@link com.netflix.hystrix.contrib.javanica.command.GenericCommand#getFallback()}
     *
     * @return method name
     *
     * getFallback()
     * 
     * @Override
     * protected Object getFallback() {
     *     final CommandAction commandAction = getFallbackAction();
     *     if (commandAction != null) {
     *         try {
     *             return process(new Action() {
     *                 @Override
     *                 Object execute() {
     *                     MetaHolder metaHolder = commandAction.getMetaHolder();
     *                     Object[] args = createArgsForFallback(metaHolder, getExecutionException());
     *                     return commandAction.executeWithArgs(metaHolder.getFallbackExecutionType(), args);
     *                 }
     *             });
     *         } catch (Throwable e) {
     *             LOGGER.error(FallbackErrorMessageBuilder.create()
     *                     .append(commandAction, e).build());
     *             throw new FallbackInvocationException(unwrapCause(e));
     *         }
     *     } else {
     *         return super.getFallback();
     *     }
     * }
     */
    public String queryUserInfoFallback(String userId) {
        return "queryUserInfo by userId:" + userId + " err!from ribbon hystrix";
    }

}
web/RibbonController.java 使用接口提供服务 From Ribbon
/**
 * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例
 * 论坛:http://bugstack.cn
 * Create by 付政委 on @2019
 */
@RestController
public class RibbonController {

    @Resource
    private RibbonService ribbonService;

    @RequestMapping(path = "/api/queryUserInfo", method = RequestMethod.GET)
    public String queryUserInfo(@RequestParam String userId) {
        return ribbonService.queryUserInfo(userId) + " From Ribbon";
    }
    
}
RibbonApplication.java 通过注解@LoadBalanced注册rest模版,用于Ribbon接口调用。并启动@EnableHystrix
/**
 * 微信公众号:bugstack虫洞栈 | 沉淀、分享、成长,专注于原创专题案例
 * 论坛:http://bugstack.cn
 * Create by 付政委 on @2019
 */
@SpringBootApplication
@EnableEurekaClient
@EnableDiscoveryClient
@EnableHystrix
public class RibbonApplication {

    public static void main(String[] args) {
        SpringApplication.run(RibbonApplication.class, args);
    }

    @Bean
    @LoadBalanced
    RestTemplate restTemplate() {
        return new RestTemplate();
    }

}
application.yml eureka服务配置,从注册中心获取可用服务
server:
  port: 9002

spring:
  application:
    name: itstack-demo-springcloud-ribbon

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:7397/eureka/

itstack-demo-springcloud-zuul | Zull路由层

Spring Cloud Zuul 路由是微服务架构的不可或缺的一部分,提供动态路由、监控、弹性、安全等的边缘服务。Zuul 是 Netflix 出品的一个基于 JVM 路由和服务端的负载均衡器。

ZuulApplication.java & 路由服务启动 ```java /**

  • 微信公众号:bugstack虫洞栈 专注原创技术专题案例
  • 论坛:http://bugstack.cn
  • Create by 付政委 on @2019 */ @SpringBootApplication @EnableZuulProxy @EnableEurekaClient @EnableDiscoveryClient public class ZuulApplication {
public static void main(String[] args) {
    SpringApplication.run(ZuulApplication.class, args);
}

}


>pom.mxl & 路由配置
```java
server:
  port: 10001

spring:
  application:
    name: itstack-demo-ddd-zuul

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:7397/eureka/

# http://localhost:10001/route-a/api/queryUserInfo?userId=111
# http://localhost:10001/route-b/api/queryUserInfo?userId=111
zuul:
  routes:
    api-a:
      path: /route-a/**
      serviceId: itstack-demo-springcloud-feign
    api-b:
      path: /route-b/**
      serviceId: itstack-demo-springcloud-ribbon

测试验证

  1. 分别启动如下系统模拟;
    1. itstack-demo-springcloud-eureka-server 服务注册发现中心
    2. itstack-demo-springcloud-eureka-client 测试接口提供方
    3. itstack-demo-springcloud-hystrix-feign 接口调用方Feign
    4. itstack-demo-springcloud-hystrix-ribbon 接口调用方Ribbon
    5. itstack-demo-springcloud-zuul 路由服务
  2. 测试接口
    1. 访问Feign、Ribbon接口,验证服务是否可用;http://localhost:9001/api/queryUserInfo?userId=111、http://localhost:9002/api/queryUserInfo?userId=111
    2. 访问路由接口A;http://localhost:10001/route-a/api/queryUserInfo?userId=111
    3. 访问路由接口B;http://localhost:10001/route-b/api/queryUserInfo?userId=111
      Hi 微信公众号:bugstack虫洞栈 111 >: from eureka client port: 8001 From Ribbon

综上总结

  1. zuul目前SpringCloud结合的是zuul 1, Netflix 已经发布了 Zuul 2但目前还未整合
  2. SpringCloud还有自己的网关服务;Spring Cloud Gateway
  3. 通过最上层的路由功能可以很方便的隔离业务,但是路由层一定是高可用的,否则路由瘫痪整个服务将不可用

上一篇:Spring Cloud(七)《基于RabbitMQ消息总线方式刷新配置服务》

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