Docker下的Spring Cloud三部曲之二：细说Spring Cloud开发

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本篇概览

  • 本文是《Docker下的Spring Cloud三部曲》系列的第二篇，详细讲解上一篇实例中用到的eureka、provider、consumer等三个应用的开发过程；

环境信息

  • 回顾一下实战环境，如下图：

源码地址

  • 上图的eureka、provider、consumer是三个spring boot的web工程，源码可以在GitHub下载，地址和链接信息如下表所示：
名称 链接 备注
项目主页 https://github.com/zq2599/blog_demos 该项目在GitHub上的主页
git仓库地址(https) https://github.com/zq2599/blog_demos.git 该项目源码的仓库地址，https协议
git仓库地址(ssh) git@github.com:zq2599/blog_demos.git 该项目源码的仓库地址，ssh协议
  • 这个git项目中有多个工程，本次实战的工程是springcloudscaledemo，如下图红框所示：

如何将spring boot工程构建成docker镜像

开发环境

  • 本次实战开发环境的具体信息如下：

    1. 操作系统：Ubuntu16；
    2. Docker版本：17.03.2-ce；
    3. JDK：1.8.0_151；
    4. maven：3.3.3；
  • 接下来我们依次开发eureka、provider、consumer等三个应用；

eureka-server应用的pom.xml

  • 新建一个名为 eureka-server的spring boot应用，pom.xml内容如下：

    <?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>

<groupId>com.bolingcavalry</groupId>
<artifactId>eureka-server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>eureka-server</name>
<description>Demo project for Spring Boot</description>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.9.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
    <spring-cloud.version>Edgware.SR1</spring-cloud.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-eureka-server</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>

        <!--新增的docker maven插件-->
        <plugin>
            <groupId>com.spotify</groupId>
            <artifactId>docker-maven-plugin</artifactId>
            <version>0.4.12</version>
            <!--docker镜像相关的配置信息-->
            <configuration>
                <!--镜像名，这里用工程名-->
                <imageName>bolingcavalry/$project.artifactId</imageName>
                <!--TAG,这里用工程版本号-->
                <imageTags>
                    <imageTag>$project.version</imageTag>
                </imageTags>
                <!--镜像的FROM，使用java官方镜像-->
                <baseImage>java:8u111-jdk</baseImage>
                <!--该镜像的容器启动后，直接运行spring boot工程-->
                <entryPoint>["java", "-jar", "/$project.build.finalName.jar"]</entryPoint>
                <!--构建镜像的配置信息-->
                <resources>
                    <resource>
                        <targetPath>/</targetPath>
                        <directory>$project.build.directory</directory>
                        <include>$project.build.finalName.jar</include>
                    </resource>
                </resources>
            </configuration>
        </plugin>
    </plugins>
</build>
</project>
  • pom.xml中的几个关键点如下：
    1. spring cloud的版本是Edgware.SR1；
    2. 添加spring-cloud-starter-eureka-server的依赖；
    3. 添加spring-cloud-dependencies的依赖(pom的形式)；
    4. 添加插件docker-maven-plugin，用于将当前工程制作成本地docker镜像；

eureka-server应用的源码

  • eureka-server应用只有一个java文件，内容如下： 
    
package com.bolingcavalry.eurekaserver;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplicationbr/>@EnableEurekaServer
public class EurekaServerApplication 

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



- 注意要添加**@EnableEurekaServer**注解；

### eureka-server的配置信息
- 配置信息application.properties的内容如下：
```properties
server.port=8080

eureka.instance.hostname=localhost
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false
eureka.client.serviceUrl.defaultZone=http://$eureka.instance.hostname:$server.port/eureka/

构建eureka-server应用的docker镜像

  • 在pom.xml文件所在目录下，执行如下命令可以构建docker镜像： 
    mvn clean package -U -DskipTests docker:build

  • 构建成功后，执行命令docker images可见新构建的镜像，如下：

    ubuntu@VM-129-56-ubuntu:~$ sudo docker images
REPOSITORY                       TAG                 IMAGE ID            CREATED             SIZE
bolingcavalry/eureka-server      0.0.1-SNAPSHOT      80663220a5f5        35 hours ago        683 MB
bolingcavalry/eureka-server      latest              80663220a5f5        35 hours ago        683 MB
  • eureka-server的镜像OK后，我们接下来构建provide的镜像；

provider应用的pom.xml

  • 新建一个名为service-provider的spring boot应用，pom.xml内容如下：

    <?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>

<groupId>com.bolingcavalry</groupId>
<artifactId>service-provider</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>service-provider</name>
<description>Demo project for Spring Boot</description>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.9.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
    <spring-cloud.version>Edgware.SR1</spring-cloud.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-eureka-server</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</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>

        <!--新增的docker maven插件-->
        <plugin>
            <groupId>com.spotify</groupId>
            <artifactId>docker-maven-plugin</artifactId>
            <version>0.4.12</version>
            <!--docker镜像相关的配置信息-->
            <configuration>
                <!--镜像名，这里用工程名-->
                <imageName>bolingcavalry/$project.artifactId</imageName>
                <!--TAG,这里用工程版本号-->
                <imageTags>
                    <imageTag>$project.version</imageTag>
                </imageTags>
                <!--镜像的FROM，使用java官方镜像-->
                <baseImage>java:8u111-jdk</baseImage>
                <!--该镜像的容器启动后，直接运行spring boot工程-->
                <entryPoint>["java", "-jar", "/$project.build.finalName.jar"]</entryPoint>
                <!--构建镜像的配置信息-->
                <resources>
                    <resource>
                        <targetPath>/</targetPath>
                        <directory>$project.build.directory</directory>
                        <include>$project.build.finalName.jar</include>
                    </resource>
                </resources>
            </configuration>
        </plugin>
    </plugins>
</build>
</project>

provider应用的源码

  • 入口类ServiceProviderApplication的源码如下： 
    
package com.bolingcavalry.serviceprovider;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@EnableDiscoveryClientbr/>@SpringBootApplication
public class ServiceProviderApplication
public static void main(String[] args)
SpringApplication.run(ServiceProviderApplication.class, args);

- 注意要添加**@EnableDiscoveryClient**注解；

- 只有一个controller类UserController ，对外提供http服务：
```java
@RestController
public class UserController 
    @RequestMapping(value = "/getuserinfo/id", method = RequestMethod.GET)
    public String getUserInfo(@PathVariable String id)
        return String.format("user[%s]", id);
    

    @RequestMapping(value = "/getuserinfo", method = RequestMethod.GET)
    public String getUserInfoWithRequestParam(@RequestParam("id") String id, @RequestParam("name") String name)
        return String.format("user [%s], id [%s], from server [%s]", name, id, getIPAddr());
    

    /**
     * 获取本机IP地址
     * @return
     */
    private static String getIPAddr()
        String hostAddress = null;
        try
            InetAddress address = InetAddress.getLocalHost();
            hostAddress = address.getHostAddress();
        catch (UnknownHostException e)
            e.printStackTrace();
        

        return hostAddress;
  • 上面的controller提供两个http服务，getUserInfoWithRequestParam服务会返回应用所在机器的IP地址；

provider的配置信息

构建provider应用的docker镜像

  • 在pom.xml文件所在目录下，执行如下命令可以构建docker镜像： 
    mvn clean package -U -DskipTests docker:build

  • 构建成功后，执行命令docker images可见新构建的镜像，如下：

    ubuntu@VM-129-56-ubuntu:~$ sudo docker images
REPOSITORY                       TAG                 IMAGE ID            CREATED             SIZE
bolingcavalry/eureka-server      0.0.1-SNAPSHOT      80663220a5f5        35 hours ago        683 MB
bolingcavalry/eureka-server      latest              80663220a5f5        35 hours ago        683 MB
bolingcavalry/service-provider   0.0.1-SNAPSHOT      a02f307bc1a9        22 hours ago        683 MB
bolingcavalry/service-provider   latest              a02f307bc1a9        22 hours ago        683 MB
  • provider已经OK，接下来是consumer工程；

consumer应用的pom.xml

  • 新建一个名为service-consumer的spring boot应用，pom.xml内容如下：

    <?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>

<groupId>com.bolingcavalry</groupId>
<artifactId>service-consumer</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>service-consumer</name>
<description>Demo project for Spring Boot</description>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.9.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
    <spring-cloud.version>Edgware.SR1</spring-cloud.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-eureka-server</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-feign</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>

        <!--新增的docker maven插件-->
        <plugin>
            <groupId>com.spotify</groupId>
            <artifactId>docker-maven-plugin</artifactId>
            <version>0.4.12</version>
            <!--docker镜像相关的配置信息-->
            <configuration>
                <!--镜像名，这里用工程名-->
                <imageName>bolingcavalry/$project.artifactId</imageName>
                <!--TAG,这里用工程版本号-->
                <imageTags>
                    <imageTag>$project.version</imageTag>
                </imageTags>
                <!--镜像的FROM，使用java官方镜像-->
                <baseImage>java:8u111-jdk</baseImage>
                <!--该镜像的容器启动后，直接运行spring boot工程-->
                <entryPoint>["java", "-jar", "/$project.build.finalName.jar"]</entryPoint>
                <!--构建镜像的配置信息-->
                <resources>
                    <resource>
                        <targetPath>/</targetPath>
                        <directory>$project.build.directory</directory>
                        <include>$project.build.finalName.jar</include>
                    </resource>
                </resources>
            </configuration>
        </plugin>
    </plugins>
</build>
</project>
  • 和前面两个应用相比，这里要引入spring-cloud-starter-feign；

consumer的源码

  • 入口类ServiceConsumerApplication 源码如下： 
    
package com.bolingcavalry.serviceconsumer;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;

@EnableDiscoveryClientbr/>@SpringBootApplication
@EnableFeignClients
public class ServiceConsumerApplication 

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



- 注意要增加**@EnableDiscoveryClient**和**@SpringBootApplication**这两个注解；

- 增加一个带注解**@FeignClient**的接口，用于在spring cloud环境中声明远程调用信息：
```java
@FeignClient(name = "microservice-provider-user")
public interface UserFeignClient 

    @RequestMapping(value = "/getuserinfo", method = RequestMethod.GET)
    String getUserInfoWithRequestParam(@RequestParam("id") String id, @RequestParam("name") String name);

  • 增加一个controller类UserFacadeController，为浏览器访问提供http服务，并且在响应请求的时候会通过UserFeignClient接口的实现远程调用provider应用的服务：

    @RestController
public class UserFacadeController 

@Autowired
private UserFeignClient userFeignClient;

@GetMapping("/user/id/name")
public String getUserInfo(@PathVariable("id") final String id, @PathVariable("name") final String name) 
    return "1. ---" + userFeignClient.getUserInfoWithRequestParam(id, name);

consumer的配置信息

构建provider应用的docker镜像

  • 在pom.xml文件所在目录下，执行如下命令可以构建docker镜像： 
    mvn clean package -U -DskipTests docker:build

  • 构建成功后，执行命令docker images可见新构建的镜像，如下：

    ubuntu@VM-129-56-ubuntu:~$docker images
REPOSITORY                       TAG                 IMAGE ID            CREATED             SIZE
bolingcavalry/service-provider   0.0.1-SNAPSHOT      a02f307bc1a9        47 hours ago        683 MB
bolingcavalry/service-provider   latest              a02f307bc1a9        47 hours ago        683 MB
bolingcavalry/service-consumer   0.0.1-SNAPSHOT      ae6b37b99754        2 days ago          683 MB
bolingcavalry/service-consumer   latest              ae6b37b99754        2 days ago          683 MB
bolingcavalry/eureka-server      0.0.1-SNAPSHOT      80663220a5f5        2 days ago          683 MB
bolingcavalry/eureka-server      latest              80663220a5f5        2 days ago          683 MB
  • 至此，本次实战所需的所有镜像都制作完毕，相关的demo工程的开发过程我们也一起过了一遍，上一章中的实战您已经可以独立做出来了，接下来的实战中，我们一起来尝试服务横向扩容；

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