SpringCloud Bus 消息总线

一、能干嘛？

二、什么是总线？

三、动态刷新全局广播

注意：必须先具备良好的RabbitMQ环境

演示广播效果，增加复杂度，再以3355为模板再制作一个3366

1、新建cloud-config-client-3366

1）POM

<?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">
    <parent>
        <artifactId>cloud2020</artifactId>
        <groupId>com.atguigu.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-config-client-3366</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-config</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>com.atguigu.springcloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>${project.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

2）YML

server:
  port: 3366

spring:
  application:
    name: config-client
  cloud:
    config:
      label: master
      name: config
      profile: dev
      uri: http://localhost:3344

eureka:
  client:
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka

management:
  endpoints:
    web:
      exposure:
        include: "*"

3）主启动

@EnableEurekaClient
@SpringBootApplication
public class ConfigClientMain3366 {
    public static void main(String[] args) {
        SpringApplication.run( ConfigClientMain3366.class,args);
    }
}

4）controller

@RestController
@RefreshScope
public class ConfigClientController {

    @Value("${server.port}")
    private String serverPort;

    @Value("${config.info}")
    private String configInfo;


    @GetMapping("/configInfo")
    public String getConfigInfo(){
        return "serverPort:"+serverPort+"	

 configInfo: "+configInfo;
    }
}

2、设计思想

1) 利用消息总线触发一个客户端/bus/refresh，进而刷新所有客户端的配置

2) 利用消息总线触发一个服务端ConfigServer的/bus/refresh端点，进而刷新所有客户端的配置（更加推荐）

图二的架构显然更加合适，图一不适合的原因如下

• 打破了微服务的职责单一性，因为微服务本身是业务模块，它本不应该承担配置刷新职责
• 破坏了微服务各节点的对等性
• 有一定的局限性。例如，微服务在迁移时，它的网络地址常常会发生变化，此时如果想要做到自动刷新，那就会增加更多的修改

3、代码改造

1）给cloud-config-center-3344配置中心服务端添加消息总线支持

POM

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-bus-amqp</artifactId>
</dependency>

YML

server:
  port: 3344

spring:
  application:
    name: cloud-config-center
  cloud:
    config:
      server:
        git:
          uri: https://github.com/jwen1994/sprincloud-config.git
          search-paths:
            - springcloud-config
          username: 526464869@qq.com
          password: wj_870096
      label: master
  rabbitmq:
    host: 192.168.216.130
    port: 5672
    username: admin
    password: password

eureka:
  client:
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka

management:
  endpoints:
    web:
      exposure:
        include: "bus-refresh"

2）给cloud-config-center-3355客户端添加消息总线支持

POM

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-bus-amqp</artifactId>
</dependency>

YML

server:
  port: 3355

spring:
  application:
    name: config-client
  cloud:
    config:
      label: master
      name: config
      profile: dev
      uri: http://localhost:3344
  rabbitmq:
    host: 192.168.216.130
    port: 5672
    username: admin
    password: password

eureka:
  client:
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka

management:
  endpoints:
    web:
      exposure:
        include: "*"

3）给cloud-config-center-3366客户端添加消息总线支持

POM

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-bus-amqp</artifactId>
</dependency>

YML

server:
  port: 3366

spring:
  application:
    name: config-client
  cloud:
    config:
      label: master
      name: config
      profile: dev
      uri: http://localhost:3344
  rabbitmq:
    host: 192.168.216.130
    port: 5672
    username: admin
    password: password

eureka:
  client:
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka

management:
  endpoints:
    web:
      exposure:
        include: "*"

4、测试

• 修改Github上配置文件增加版本号
• curl -X POST "http://localhost:3344/actuator/bus-refresh"
• 一次发送，处处生效

四、动态刷新定点通知

不想全部通知，只想定点通知

• 只通知3355
• 不通知3366

公式：http://配置中心IP地址/actuator/bus-refresh/{destination}

/bus/refresh请求不再发送到具体的服务实例上，而是发给config server并通过destination参数类指定需要更新配置的服务或实例

我们这里以刷新运行在3355端口上的config-client为例

curl -X POST "http://localhost:3344/actuator/bus-refresh/config-client:3355"

五、总结