Spring Boot實戰系列(7)集成Consul配置中心

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本篇主要介紹了 Spring Boot 如何與 Consul 進行集成，Consul 只是服務注冊的一種實現，還有其它的例如 Zookeeper、Etcd 等，服務注冊發現在微服務架構中扮演這一個重要的角色，伴隨着服務的大量出現，服務與服務之間的配置管理、運維管理也變的難以維護，通過 Consul 可以解決這些問題，實現服務治理、服務監控。

關於 Consul 的更多知識點不在這里贅述，但是在學習本節之前還是希望您能先了解下，請移步我之前寫的 微服務服務注冊發現之 Consul 系列

快速導航

• 添加 Consul Maven依賴
• 系統級配置文件&應用級配置文件
• 配置Consul管理控制台
• 項目構建
  • 建立Config獲取Consul配置數據
  • 編寫啟動類調用配置
• 接口測試
• 總結

注意：以下代碼示例可在Github查看項目完整示例 chapter7-1

添加maven依賴

在 Spring Boot 項目的 pom.xml 文件中引入 spring-cloud-starter-consul-discovery 啟動器

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-consul-discovery</artifactId>
    <version>2.1.1.RELEASE</version>
</dependency>

使用 Consul 配置信息時需要引入 spring-cloud-starter-consul-config 依賴

 <dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-consul-config</artifactId>
</dependency>
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配置文件

系統級配置文件 bootstrap.yml

使用 Spring Cloud Consul Config，需要配置以下信息在 bootstrap.yml 文件

• spring.cloud.consul.host：配置consul地址
• spring.cloud.consul.port：配置consul端口
• spring.cloud.consul.config.prefix：配置基本文件，默認值config
• spring.cloud.consul.config.enabled：啟動consul配置中心
• spring.cloud.consul.config.format：consul上面文件的格式 YAML、FILES、PROPERTIES、默認 KEY-VALUE
• spring.cloud.consul.config.data-key：表示 consul 上面的 KEY 值(或者說文件的名字)，默認是 data

bootstrap.yml

spring:
  cloud:
    consul:
      host: 192.168.6.128
      port: 8500
      config:
        prefix: config
        enabled: true
        format: YAML
        data-key: user
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應用級配置文件 application.yml

定義應用級別的配置在 bootstrap.yml 之后加載，例如搭配 spring-cloud-config 使用。

• spring.cloud.consul.host：配置consul地址
• spring.cloud.consul.port：配置consul端口
• spring.cloud.consul.discovery.enabled：啟用服務發現
• spring.cloud.consul.discovery.register：啟用服務注冊
• spring.cloud.consul.discovery.deregister：服務停止時取消注冊
• spring.cloud.consul.discovery.prefer-ip-address：表示注冊時使用IP而不是hostname
• spring.cloud.consul.discovery.health-check-interval：健康檢查頻率
• spring.cloud.consul.discovery.health-check-path：健康檢查路徑
• spring.cloud.consul.discovery.health-check-critical-timeout：健康檢查失敗多長時間后，取消注冊
• spring.cloud.consul.discovery.instance-id：服務注冊標識

server:
  port: 8082
spring:
  application:
    name: consul-service
  profiles:
    active: dev
  cloud:
    consul:
      host: 192.168.6.128
      port: 8500
      discovery: # 服務發現配置
        enabled: true
        register: true
        deregister: true
        prefer-ip-address: true
        health-check-interval: 10s
        health-check-critical-timeout: 30s
        health-check-path: /health
        instance-id: ${spring.application.name}:${spring.cloud.client.ip-address}:${server.port} # 應用名稱+服務器IP+端口
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配置Consul管理控制台

Consul 提供了 Key/Value 存儲用於存儲配置數據，在 Spring Cloud Consul 中配置默認存儲於 /config 文件夾下，根據應用程序名和模擬 Spring Cloud Config 順序解析屬性的規則來配置文件。

在本例中操作 Consul 管控台建立以下路徑配置：

• config：為配置基本文件，這里默認為 config。
• consul-service：為 application.yml 中配置的 spring.application.name 值。
• dev：為 application.yml 中配置的 spring.profiles.active 值，也是本程序設置環境變量意為開發環境。
• user.yml：為配置的文件名，格式為 yml 格式。

config/consul-service.dev/user.yml
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最終為 Consul 管控台建立的配置數據如下圖所示：

項目構建

注意：以下只貼核心代碼，源碼參見：Github chapter7-1

建立Config獲取Consul配置數據

• 獲取student配置數據

注意以下屬性名要與在 Consul 管控台中配置的一一對應。

@ConfigurationProperties 進行屬性注入

config/StudentConfig.java

@ConfigurationProperties(prefix = "student")
public class StudentConfig {
    private String name;
    private int age;
<span class="token keyword">public</span> String <span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> name<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setName</span><span class="token punctuation">(</span>String name<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">getAge</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> age<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setAge</span><span class="token punctuation">(</span><span class="token keyword">int</span> age<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>age <span class="token operator">=</span> age<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> String <span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token string">"大家好我是"</span> <span class="token operator">+</span> name <span class="token operator">+</span> <span class="token string">"，今年"</span> <span class="token operator">+</span> age <span class="token operator">+</span> <span class="token string">"歲，我是一名在校大學生！"</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

}
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• 獲取teach配置數據

同以上 student 配置，我們可以將不同類型的配置分文件進行配置定義

@ConfigurationProperties(prefix = "teach")
public class TeachConfig {
    private String name;
    private String course;
<span class="token keyword">public</span> String <span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> name<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setName</span><span class="token punctuation">(</span>String name<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> String <span class="token function">getCourse</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> course<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setCourse</span><span class="token punctuation">(</span>String course<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>course <span class="token operator">=</span> course<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> String <span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token string">"大家好我是"</span> <span class="token operator">+</span> name <span class="token operator">+</span> <span class="token string">"，是一名大學老師！教同學們學習"</span> <span class="token operator">+</span> course<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

}
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編寫啟動類調用配置

注解說明：

• EnableDiscoveryClient：讓注冊中心進行服務發現，將服務注冊到服務組件上。
• RestController：是 @ResponseBody 和 @Controller 注解的組合，注明該注解后整個類所有的方法返回值為json格式。
• SpringBootApplication：SpringBoot 的啟動注解。
• EnableConfigurationProperties：屬性配置的 class 添加到 SpringBoot 的屬性配置注解里，否則不能通過 @Autowired 注解注入我們定義的屬性配置類。

接口說明：

• /health：健康檢查接口
• /user/description：@Value 注解獲取用戶信息描述接口
• /user/student/intro：@ConfigurationProperties 獲取學生簡介信息接口
• /user/teach/intro：@ConfigurationProperties 獲取教師簡介信息接口

@EnableDiscoveryClient
@RestController
@SpringBootApplication
@EnableConfigurationProperties({ StudentConfig.class, TeachConfig.class })
public class ConsulApplication {
<span class="token annotation punctuation">@Value</span><span class="token punctuation">(</span><span class="token string">"${description}"</span><span class="token punctuation">)</span>
<span class="token keyword">private</span> String description<span class="token punctuation">;</span>

<span class="token annotation punctuation">@Autowired</span>
<span class="token keyword">private</span> StudentConfig studentConfig<span class="token punctuation">;</span>

<span class="token annotation punctuation">@Autowired</span>
<span class="token keyword">private</span> TeachConfig teachConfig<span class="token punctuation">;</span>

<span class="token annotation punctuation">@GetMapping</span><span class="token punctuation">(</span><span class="token string">"/health"</span><span class="token punctuation">)</span>
<span class="token keyword">public</span> String <span class="token function">Health</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"health"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token keyword">return</span> <span class="token string">"OK"</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token annotation punctuation">@GetMapping</span><span class="token punctuation">(</span><span class="token string">"/user/description"</span><span class="token punctuation">)</span>
<span class="token keyword">public</span> String <span class="token function">Description</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> description<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token annotation punctuation">@GetMapping</span><span class="token punctuation">(</span><span class="token string">"/user/student/intro"</span><span class="token punctuation">)</span>
<span class="token keyword">public</span> String <span class="token function">StudentIntro</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> studentConfig<span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token annotation punctuation">@GetMapping</span><span class="token punctuation">(</span><span class="token string">"/user/teach/intro"</span><span class="token punctuation">)</span>
<span class="token keyword">public</span> String <span class="token function">TeachIntro</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> teachConfig<span class="token punctuation">.</span><span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    SpringApplication<span class="token punctuation">.</span><span class="token function">run</span><span class="token punctuation">(</span>ConsulApplication<span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">,</span> args<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

}
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接口測試

• 健康檢查接口

該接口在服務啟動后且向 Consul 配置中心注冊后，根據 application.yml 文件配置的 health-check-interval 和 health-check-path屬性進行自動調用。

$ curl http://127.0.0.1:8082/health
OK!

注冊成功后展示我們服務的名稱及健康檢查結果如下：

• 獲取教師簡介配置接口

$ curl http://127.0.0.1:8082/user/teach/intro
大家好我是Teach Li，是一名大學老師！教同學們學習Java軟件開發!
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• 獲取學生簡介配置接口

$ curl http://127.0.0.1:8082/user/student/intro
大家好我是Jack，今年18歲，我是一名在校大學生！
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• 采用 @Value 注解獲取項目描述接口

$ curl http://127.0.0.1:8082/user/description
用戶信息描述
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總結

這里我們只介紹了 Consul 在 Spring Boot 的配置功能，關於 Consul 做為注冊中心在下一章節中介紹，本篇中需要注意通過 @Value 注入的屬性，修改 Consul 后需要重啟服務才能生效，通過 @ConfigurationProperties 注入的屬性，在 Consul 管控台修改屬性之后可立即生效。

如遇到其他什么可在SpringBoot-Course issues中提問

資料

• 個人博客： Node.js技術棧
• Spring Boot 實戰系列：https://github.com/Q-Angelo/SpringBoot-Course
• 項目源碼： Github查看本文完整示例 chapter7-1