作者:jiangzz
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在微服务架构的系统中, 我们通常会使用轻量级的消息代理来构建一个共用的消息主题让系统中所有微服务实例都连接上来, 由于该主题中产生的消息会被所有实例监听和消费, 所以我们称它为消息总线。在总线上的各个实例都可以方便地广播一些需要让其他连接在该主题上的实例都知道的消息, 例如配置信息的变更或者其他一些管理操作等。由于消息总线在微服务架构系统中被广泛使用, 所以它同配置中心一样, 几乎是微服务架构中的必备组件。Spring Cloud 作为微服务架构综合性的解决方案,对此自然也有自己的实现, 这就是本章我们将要具体介绍的Spring Cloud Bus。通过使用 Spring Cloud Bus, 可以非常容易地搭建起消息总线, 同时实现了一些消息总线中的常用功能, 比如, 配合Spring Cloud Config 实现微服务应用配置信息的动态更新等。
配置服务端集成 Kafka bus
在配置服务器中添加如下依赖
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>1.8</java.version>
</properties>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.5.RELEASE</version>
</parent>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Greenwich.SR1</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-config-server</artifactId>
</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-bus-kafka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-bus</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
在application.proeprties添加如下
server.port = 8080
# 连接远程git读取配置信息
spring.cloud.config.server.git.uri = https://github.com/jiangzz/applicationconfig.git
spring.cloud.config.server.git.clone-on-start=true
spring.cloud.config.server.git.refresh-rate=5
spring.cloud.config.server.git.repos.aa.search-paths=app1
spring.cloud.config.server.git.repos.aa.clone-on-start=true
spring.cloud.config.server.git.repos.aa.pattern=app*
spring.cloud.config.server.git.repos.aa.uri=https://github.com/jiangzz/applicationconfig.git
spring.cloud.config.server.git.repos.aa.refresh-rate=5
management.endpoints.web.exposure.include=*
## 配置eureka
spring.application.name=CONFIG-SERVICE
eureka.instance.instance-id=001
eureka.instance.prefer-ip-address=true
eureka.instance.lease-expiration-duration-in-seconds=20
eureka.instance.lease-renewal-interval-in-seconds=10
eureka.client.register-with-eureka=true
eureka.client.healthcheck.enabled=true
eureka.client.fetch-registry=false
eureka.client.service-url.defaultZone=http://jiangzz:123456@localhost:8761/eureka/
# 配置bus总线
spring.kafka.bootstrap-servers=CentOS:9092,CentOS:9093,CentOS:9094
本机必须配置CentOS主机名和ip的映射关系,启动SpringBootConfigServer如下
@SpringBootApplication
@EnableConfigServer
public class SpringBootConfigServer {
public static void main(String[] args) {
SpringApplication.run(SpringBootConfigServer.class,args);
}
}
启动该服务,可以在Kafka消息服务器中看到
[root@CentOS kafka_2.11-2.2.0]# ./bin/kafka-topics.sh --zookeeper CentOS:2181 --list
springCloudBus
配置客户端集成 Kafka bus
在pom文件中添加如下依赖
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>1.8</java.version>
</properties>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.5.RELEASE</version>
</parent>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Greenwich.SR1</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<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.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>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-bus-kafka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-bus</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
application.properties内容如下
server.servlet.context-path= /SpringCloudConfigClient
bootstrap.properties内容如下
# 指定连接的配置服务名字
spring.application.name=app1
spring.cloud.config.profile=test
spring.cloud.config.label=master
spring.cloud.config.name= SpringCloudConfigServer
spring.cloud.config.discovery.enabled=true
spring.cloud.config.discovery.service-id=CONFIG-SERVICE
# 开启所有的健康检查
management.endpoints.web.exposure.include=*
## 配置Eureka
eureka.client.fetch-registry=true
eureka.client.register-with-eureka=false
eureka.client.service-url.defaultZone=http://jiangzz:123456@localhost:8761/eureka/
# 配置bus总线
spring.kafka.bootstrap-servers=CentOS:9092,CentOS:9093,CentOS:9094
TestController内容如下
@RefreshScope
@RestController
public class TestController {
@Value("${server.port}")
private int port;
@RequestMapping
public int test(){
return port;
}
}
ConfigClientApplication代码如下
@SpringBootApplication
public class ConfigClientApplication {
public static void main(String[] args) {
SpringApplication.run(ConfigClientApplication.class,args);
}
}
此时,用户尝试更新git仓库的配置信息,然后在配置服务器上执行,就可以看到所有的服务器都会刷新自身的配置信息。
curl.exe -X POST http://localhost:8080//actuator/bus-refresh
如果用户想去更新指定的一些服务器可以指定服务器的名字和端口
curl.exe -X POST http://localhost:8080/actuator/bus-refresh/app1:7077