使用Maven插件构建Docker镜像,推送Docker镜像到DockerHub

stefania-crudeli-unsplash.jpg

基础环境

• 已成功安装Docker，本地可以正常使用。
• 本地安装有Java编辑器，本文中使用的是IDEA。

进入正题

1. 请确保开启Docker远程API访问

开启方式请参考DooD:Docker+Jenkins
配置成功后再docker所在的服务器可以看到2375端口已经开启

Docker开启远程访问

2. 配置本地环境变量

如下图所示，配置环境变量：DOCKER_HOST，值为tcp://IP:Port；此处的IP为Docker所安装的服务器的IP

environment_variables

3. 构建一个SpringBoot项目

• 此处我使用的是IDEA新建的Spring Boot项目，如下图

  
  
  

  Spring Initializr.png

• 项目目录结构如下

  
  
  

  project_structure

4. pom.xml引入dockerfile-maven-plugin插件

    dockerlgf
    1.4.4


    com.spotify
    dockerfile-maven-plugin
    ${com.spotify.version} 
    
        
        ${docker.image.prefix}/${project.artifactId}
       
        ${project.version}
        
           
            target/${project.build.finalName}.jar
        
    

5. 为第三步新建的项目编写一个简单的Dockerfile

# 基础镜像：openjdk:8-jdk-alpine
FROM openjdk:8-jdk-alpine
# 挂载目录，默认的安装jar包位置：/tmp
VOLUME /tmp
# 上一步在pom.xml指定的JAR_FILE参数 
ARG JAR_FILE
# 将上一步的jar包copy到镜像中的根目录，并重命名为app.jar
COPY ${JAR_FILE} app.jar
# 启动jar包
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]

6. 使用maven命令构建一个Docker镜像

• 运行mvn clean package dockerfile:build来构建一个Docker image，控制台输出如下

[INFO] --- dockerfile-maven-plugin:1.4.4:build (default-cli) @ spring-boot-docker ---
[INFO] Building Docker context E:\Java\code\spring-boot-docker
[INFO] 
[INFO] Image will be built as dockerlgf/spring-boot-docker:0.0.1-SNAPSHOT
[INFO] 
[INFO] Step 1/5 : FROM openjdk:8-jdk-alpine
[INFO] 
[INFO] Pulling from library/openjdk
[INFO] Image 4fe2ade4980c: Pulling fs layer
[INFO] Image 6fc58a8d4ae4: Pulling fs layer
[INFO] Image ef87ded15917: Pulling fs layer
[INFO] Image 6fc58a8d4ae4: Downloading
[INFO] Image 6fc58a8d4ae4: Verifying Checksum
[INFO] Image 6fc58a8d4ae4: Download complete
[INFO] Image 4fe2ade4980c: Downloading
[INFO] Image 4fe2ade4980c: Verifying Checksum
[INFO] Image 4fe2ade4980c: Download complete
[INFO] Image 4fe2ade4980c: Extracting
[INFO] Image ef87ded15917: Downloading
[INFO] Image 4fe2ade4980c: Pull complete
[INFO] Image 6fc58a8d4ae4: Extracting
[INFO] Image 6fc58a8d4ae4: Pull complete
[INFO] Image ef87ded15917: Download complete
[INFO] Image ef87ded15917: Extracting
[INFO] Image ef87ded15917: Pull complete
[INFO] Digest: sha256:b18e45570b6f59bf80c15c78d7f0daff1e18e9c19069c323613297057095fda6
[INFO] Status: Downloaded newer image for openjdk:8-jdk-alpine
[INFO]  ---> 97bc1352afde
[INFO] Step 2/5 : VOLUME /tmp
[INFO] 
[INFO]  ---> Running in 814c0afe6c60
[INFO] Removing intermediate container 814c0afe6c60
[INFO]  ---> 7754756ce600
[INFO] Step 3/5 : ARG JAR_FILE
[INFO] 
[INFO]  ---> Running in 97f2dc95ae80
[INFO] Removing intermediate container 97f2dc95ae80
[INFO]  ---> ec17923a3707
[INFO] Step 4/5 : COPY ${JAR_FILE} app.jar
[INFO] 
[INFO]  ---> ec366faad7ad
[INFO] Step 5/5 : ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]
[INFO] 
[INFO]  ---> Running in 44152e10f872
[INFO] Removing intermediate container 44152e10f872
[INFO]  ---> 31f6c6947a0b
[INFO] Successfully built 31f6c6947a0b
[INFO] Successfully tagged dockerlgf/spring-boot-docker:0.0.1-SNAPSHOT
[INFO] 
[INFO] Detected build of image with id 31f6c6947a0b
[INFO] Building jar: E:\Java\code\spring-boot-docker\target\spring-boot-docker-0.0.1-SNAPSHOT-docker-info.jar
[INFO] Successfully built dockerlgf/spring-boot-docker:0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS

• 在Docker安装的服务器上，已经可以看到最新构建的镜像

  
  
  

  docker_image

7. 配置Maven命令默认执行dockerfile命令

• 在上一步我们看到需要执行dockerfile相关的maven命令才可以执行，为了方便，我们可以将不同的dockerfile命令绑定到不同的maven phase.如下图所示。

  
  
  

  dockerfileComand_maven
• 绑定方式是在pom.xml中添加相应的配置，如下所示

  com.spotify
  dockerfile-maven-plugin
  ${dockerfile-maven-version}
  
    
      default
      
        build
        push
      
    
  
  
    ${docker.image.prefix}/${project.artifactId}
    ${project.version}
    
      ${project.build.finalName}.jar
    
  

此时，执行mvn package == mvn package + dockerfile:build
执行 mvn deploy == mvn deploy +dockerfile:push

8. push镜像到dockerhub或private registry

官网讲到有两种方式

• 第一种：Authenticating with maven pom.xml:从1.3.XX版本以后,至此在pom.xml中直接配置username和password来完成push到dockerhub或者private registry,或者在命令行执行时指定mvn goal -Ddockerfile.username=... -Ddockerfile.password=...
  目前我只测试成功了这一种方式，pom.xml中配置如下

    
        
            com.spotify
            dockerfile-maven-plugin
            ${com.spotify.version}
            
                
                dockerlgf
               
                xxxxxx
                true
                ${docker.image.prefix}/${project.artifactId}
                ${project.version}
                
                  target/${project.build.finalName}.jar
                
            
        
    

• 第二种：Authenticating with maven settings.xml:从1.3.6版本以后,可以通过在maven settings.xml配置server信息,pom.xml只需要添加下面的配置

pom.xml

  
  docker-repo.example.com:8080/organization/image
  latest
  true

maven settings.xml

  
    docker-repo.example.com:8080
    me
    mypassword
  

9 参考文章

• Spring Boot with Docker
• dockerfile-maven-plugin官网
• https://blog.csdn.net/lvyuan1234/article/details/69255944
• https://segmentfault.com/a/1190000010313412