微服務SpringCloud之配置中心和消息總線

時間 2019-11-06

原文原文鏈接

在微服務SpringCloud之Spring Cloud Config配置中心SVN博客中每一個client刷新配置信息時須要post請求/actuator/refresh,但客戶端愈來愈多時，，須要每一個客戶端都執行一遍，這種方案就不太適合了。使用Spring Cloud Bus能夠完美解決這一問題。html

1、Spring Cloud Busjava

Spring cloud bus經過輕量消息代理鏈接各個分佈的節點。這會用在廣播狀態的變化（例如配置變化）或者其餘的消息指令。Spring bus的一個核心思想是經過分佈式的啓動器對spring boot應用進行擴展，也能夠用來創建一個多個應用之間的通訊頻道。目前惟一實現的方式是用AMQP消息代理做爲通道，一樣特性的設置（有些取決於通道的設置）在更多通道的文檔中。git

Spring cloud bus被國內不少都翻譯爲消息總線，也挺形象的。你們能夠將它理解爲管理和傳播全部分佈式項目中的消息既可，其實本質是利用了MQ的廣播機制在分佈式的系統中傳播消息，目前經常使用的有Kafka和RabbitMQ。利用bus的機制能夠作不少的事情，其中配置中心客戶端刷新就是典型的應用場景之一，咱們用一張圖來描述bus在配置中心使用的機制。github

2、啓動RabbitMqweb

啓動RabbitMq的具體方法以前博客已經寫了，略過。spring

3、SpringCloud Config Server端apache

1.引入依賴tomcat

Demo是在上篇博客的基礎上進行修改，主要增長引入spring-cloud-starter-bus-amqp。maven

<?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>2.1.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>SpringCloudConfigServer</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>
    <name>SpringCloudConfigServer</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR2</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</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.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-bus-amqp</artifactId>
    </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</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>

View Code

2.新增RabbitMq配置信息分佈式

這裏主要增長開啓消息跟蹤、配置rabbitmq相關信息。

spring.cloud.bus.trace.enabled=true
spring.rabbitmq.host=127.0.0.1
spring.rabbitmq.port=5672
spring.rabbitmq.username=guest
spring.rabbitmq.password=guest
management.endpoints.web.exposure.include=*

4、SpringCloud Config Client端

1.引入依賴

Client端和服務端有相似的配置，也是引入spring-cloud-starter-bus-amqp，增長rabbitmq相關配置。

<?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>2.1.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>SpringCloudConfigClient</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>
    <name>SpringCloudConfigClient</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR2</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-config</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-netflix-eureka-client</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-bus-amqp</artifactId>
</dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</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>

View Code

2.新增RabbitMq配置信息

management.endpoints.web.exposure.include=*
## 開啓消息跟蹤
spring.cloud.bus.trace.enabled=true
spring.rabbitmq.host=127.0.0.1
spring.rabbitmq.port=5672
spring.rabbitmq.username=guest
spring.rabbitmq.password=guest

5、測試

1.依次啓動EurekaServer、SpringCloudConfigServer、SpringCloudConfigClient，輸入http://localhost:8001/neo-config/dev、http://localhost:8003/hello。

2.修改配置信息

修改github上的配置信息，再次輸入上面的url，在8003端口的是沒有更新的，此時須要post請求http://localhost:8001/actuator/bus-refresh來刷新SpringCloudConfigServer。這裏在post請求時可能會出現40五、404的錯誤，須要設置management.endpoints.web.exposure.include=*，而且因爲springcloud的版本不一樣，post請求的url也不一樣。

post請求以後返回204，而後刷新便可看到最新的配置信息。

參考:http://www.ityouknow.com/springcloud/2017/05/26/springcloud-config-eureka-bus.html