dockerfile-maven-plugin 使用

这是一个简单的Springboot示例,用于演示 dockerfile-maven-plugin 把Maven项目生成Docker Image并Push到私有Registry。

com.spotify有两个插件,网上的资料大都基于老的docker-maven-plugin，在其主页上已经说明：

我们建议新项目使用dockerfile-maven。docker-maven-plugin将不再具有新功能或接受新功能的PR。但是，我们将继续提供BUG修复。
这个插件是Spotify用于从Java服务构建Docker Image的初始Maven插件。它最初创建于2014年，当时我们第一次开始尝试使用Docker。此插件能够根据pom.xml文件中的配置为您生成Dockerfile，用于FROM Image，使用ADD / COPY添加的资源等。随着时间的推移，我们已经意识到从Java项目构建Docker Image的最简单方法是让开发人员编写Dockerfile。这个插件围绕生成Dockerfiles，将项目目录复制到“staging”目录以用作Docker构建上下文等的行为最终导致了很多不必要的混淆，因为我们的用户引入了额外的抽象和需求用于配置Docker提供的功能。这导致了用于构建docker Image的第二个Maven插件，dockerfile-maven，我们认为这提供了一个更简单的使用Maven生成Docker Image的方法。

虽然说是更简单,但是实际使用中因为文档比较简略,还是有坑的,现记录如下。

报错：
Could not acquire image ID or digest following build
在1.3.X版本会出现，更新到1.4.X后修复。
报错：
Deployment failed: repository element was not specified in the POM inside distributionManagement element or in -DaltDeploymentRepository=id::layout::url parameter

引入插件

<plugin>
 <groupId>org.apache.maven.plugins</groupId>
 <artifactId>maven-deploy-plugin</artifactId>
 <configuration>
 <skip>true</skip>
 </configuration> 
</plugin>

dockerfile-maven-plugin Maven Goals：

Maven Goals

Goals available for this plugin:

Goal	Description	Default Phase
`dockerfile:build`	Builds a Docker image from a Dockerfile.	package
`dockerfile:tag`	Tags a Docker image.	package
`dockerfile:push`	Pushes a Docker image to a repository.	deploy

Skip Docker Goals Bound to Maven Phases

You can pass options to maven to disable the docker goals.

Maven Option	What Does it Do?	Default Value
`dockerfile.skip`	Disables the entire dockerfile plugin; all goals become no-ops.	false
`dockerfile.build.skip`	Disables the build goal; it becomes a no-op.	false
`dockerfile.tag.skip`	Disables the tag goal; it becomes a no-op.	false
`dockerfile.push.skip`	Disables the push goal; it becomes a no-op.	false

如果package时不想打包Image可以这样:

mvn clean package -Ddockerfile.skip

Configuration

Build Phase

Maven Option	What Does it Do?	Required	Default Value
`dockerfile.contextDirectory`	Directory containing the Dockerfile to build.	yes	none
`dockerfile.repository`	The repository to name the built image	no	none
`dockerfile.tag`	The tag to apply when building the Dockerfile, which is appended to the repository.	no	latest
`dockerfile.build.pullNewerImage`	Updates base images automatically.	no	true
`dockerfile.build.noCache`	Do not use cache when building the image.	no	false
`dockerfile.build.cacheFrom`	Docker image used as cache-from. Pulled in advance if not exist locally or `pullNewerImage` is `false`	no	none
`dockerfile.buildArgs`	Custom build arguments.	no	none
`dockerfile.build.squash`	Squash newly built layers into a single new layer (experimental API 1.25+).	no	false

示例代码

POM

<project>
<properties>
 <java.version>1.8</java.version>
 <!--docker私服地址-->
 <docker.repostory>192.168.87.110:5000</docker.repostory>
  </properties>
<!--略-->
  <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-deploy-plugin</artifactId>
                <configuration>
                    <skip>true</skip>
                </configuration>
            </plugin>
            <plugin>
                <groupId>com.spotify</groupId>
                <artifactId>dockerfile-maven-plugin</artifactId>
                <version>1.4.10</version>
                <executions>
                    <execution>
                        <id>default</id>
                        <goals>
                            <!--如果package时不想用docker打包,就注释掉这个goal-->
                            <goal>build</goal>
                            <goal>push</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>                
                    <repository>${docker.repostory}/${project.artifactId}</repository>
                    <tag>${project.version}</tag>
                    <buildArgs>
                        <!--提供参数向Dockerfile传递-->
                        <JAR_FILE>target/${project.build.finalName}.jar</JAR_FILE>
                    </buildArgs>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Dockerfile文件

FROM openjdk:8u191-jre-alpine3.9
ENTRYPOINT ["/usr/bin/java", "-jar", "/app.jar"]
ARG JAR_FILE
ADD ${JAR_FILE} /app.jar
EXPOSE 8080

打包并推送
mvn deploy

请确认能登录registry

cat ~/.docker/config.json

{
    "auths": {
        "192.168.87.110:5000": {
            "auth": "YWRtaW46JKDtaW4xMjM="
        }
    },
    "HttpHeaders": {
        "User-Agent": "Docker-Client/18.09.0 (linux)"
    }
}

如果没有，docker login 192.168.87.110:5000
手工这样是不方便的，可以配置处理，请参阅
Authentication
可以在maven settings.xml或pom.xml中配置，如果要对settings.xml中的密码进行加密，请参阅Password Encryption (从Version 1.4.3支持)

Demo源码

使用dockerfile-maven-plugin打包maven项目为docker image