用簡單的方式來做不同AP的設定同步，使用 SpringCloud 跟 RabbitMQ

Spring Cloud Config Server

簡單說，你Server端可以從GitHub上或是本地檔案載入設定檔，當Client端啟動時會去Server上拉需要的設定參數下來

Server端

build.gradle

buildscript {
    ext {
        springBootVersion = '1.2.5.RELEASE'
    }
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}") 
        classpath("io.spring.gradle:dependency-management-plugin:0.5.2.RELEASE")
    }
}

apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
apply plugin: 'spring-boot' 
apply plugin: 'io.spring.dependency-management' 

jar {
    baseName = 'Demo-Server'
    version = '0.0.1-SNAPSHOT'
}
sourceCompatibility = 1.8
targetCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
	compile("org.springframework.cloud:spring-cloud-config-server:1.0.2.RELEASE")
    testCompile("org.springframework.boot:spring-boot-starter-test") 
}

eclipse {
    classpath {
         containers.remove('org.eclipse.jdt.launching.JRE_CONTAINER')
         containers 'org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8'
    }
}

server:
  port: 8888

spring:
  cloud:
    config:
      server:
        git :
          uri: https://github.com/samzhu/microservices-lab-configuration

bootstrap.yml

spring:
  application:
    name: config-service

ConfigServerApplication.java

package demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.config.server.EnableConfigServer;

@SpringBootApplication
@EnableConfigServer
public class ConfigServerApplication {

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

Client端

build.gradle

buildscript {
    ext {
        springBootVersion = '1.2.5.RELEASE'
    }
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}") 
        classpath("io.spring.gradle:dependency-management-plugin:0.5.2.RELEASE")
    }
}

apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
apply plugin: 'spring-boot' 
apply plugin: 'io.spring.dependency-management' 

jar {
    baseName = 'Demo-Client'
    version = '0.0.1-SNAPSHOT'
}
sourceCompatibility = 1.8
targetCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
	compile('org.springframework.cloud:spring-cloud-config-client:1.0.2.RELEASE')
	compile('org.springframework.boot:spring-boot-starter-web')
	compile('org.springframework.boot:spring-boot-starter-actuator')
  testCompile("org.springframework.boot:spring-boot-starter-test") 
}

eclipse {
    classpath {
         containers.remove('org.eclipse.jdt.launching.JRE_CONTAINER')
         containers 'org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8'
    }
}

application.yml

server:
  port: 8080

spring:
  application:
    name: config-client
  cloud:
    config:
      uri: http://localhost:8888

Application.java

package demo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.core.env.Environment;

@SpringBootApplication
public class Application {

	@Autowired
	void setEnvironment(Environment e) {
		System.out.println(e.getProperty("configuration.projectName"));
	}

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

ProjectNameRestController.java

package demo;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RefreshScope
public class ProjectNameRestController {

	@Value("${configuration.projectName}")
	private String projectName;

	@RequestMapping("/project-name")
	public String projectName() {
		return this.projectName;
	}
}

啟動後Client可以從Server取得GitHub上的設定值

config-client.properties

configuration.projectName=Spring Cloud

向Server端確認參數

curl -X GET 'http://localhost:8888/config-client/master'

{
  "name": "config-client",
  "profiles": [
    "master"
  ],
  "label": "master",
  "propertySources": [
    {
      "name": "https://github.com/samzhu/microservices-lab-configuration/config-client.properties",
      "source": {
        "configuration.projectName": "Spring Cloud"
      }
    }
  ]
}

向Client取得project-name

curl -X GET 'http://localhost:8080/project-name'

Spring Cloud

更新GitHub上的檔案

configuration.projectName=Spring Cloud Sam Test

觸發Client更新

curl -X POST 'http://localhost:8080/refresh'

[
    "configuration.projectName"
]

再檢查可以發現已經更新了

curl -X GET 'http://localhost:8080/project-name'

Spring Cloud Sam Test

但是這樣子還是必須每一台 Client 去觸發 Refresh，所以 Spring Cloud 提供一個做法透過 RabbitMQ 來觸發

修改 Client 部分

build.gradle 增加 dependencies

compile('org.springframework.cloud:spring-cloud-starter-bus-amqp:1.0.3.RELEASE')

application.yml 增加 rabbitmq 部分

spring:
  rabbitmq:
    addresses: ${vcap.services.${PREFIX:}rabbitmq.credentials.uri:amqp://${RABBITMQ_HOST:192.168.56.102}:${RABBITMQ_PORT:5672}}

安裝 RabbitMQ Server

練習安裝在Ububtu上

echo "deb http://www.rabbitmq.com/debian/ testing main" | sudo tee -a /etc/apt/sources.list.d/rabbitmq.list

# 加入 APT repository
wget https://www.rabbitmq.com/rabbitmq-signing-key-public.asc
sudo apt-key add rabbitmq-signing-key-public.asc

sudo apt-get update

# 安裝 RabbitMQ server 套件
sudo apt-get install rabbitmq-server

# 啟用 RabbitMQ Management Web Console
sudo rabbitmq-plugins enable rabbitmq_management

# 開啟遠端使用者可登入 web console
sudo sh -c "echo '[{rabbit, [{loopback_users, []}]}].' > /etc/rabbitmq/rabbitmq.config"
sudo service rabbitmq-server restart

# 開啟瀏覽器使用 guest guest 登入觀察
http://192.168.56.102:15672/

之後啟動兩個 Client

java -jar Demo-Client-0.0.1-SNAPSHOT.jar
java -jar Demo-Client-0.0.1-SNAPSHOT.jar --server.port=9000

重複上面動作 更新 GitHub檔案後
對 Client 8080 送出更新指令

curl -X POST 'http://localhost:8080/bus/refresh'

可以發現 Client 9000 也更新了

curl -X GET 'http://localhost:9000/project-name'