Using com.spotify:dockerfile-maven-plugin with multi-project poms.

pom-child.xml

<plugin>
  <groupId>com.spotify</groupId>
  <artifactId>dockerfile-maven-plugin</artifactId>
  <configuration>
    <repository>${docker.registry}/${docker.image}</repository>
    <tag>${docker.tag}</tag>
    <buildArgs>
      <JAR_FILE>${project.build.finalName}.jar</JAR_FILE>
    </buildArgs>
    <skip>${dockerfile.skip}</skip>
  </configuration>
  <executions>
    <execution>
      <id>default</id>
      <goals>
        <goal>build</goal>
        <goal>push</goal>
      </goals>
    </execution>
  </executions>
</plugin>

pom-parent.xml

<plugin>
  <groupId>com.spotify</groupId>
  <artifactId>dockerfile-maven-plugin</artifactId>
  <version>1.3.6</version>
  <configuration>
    <skip>true</skip>
  </configuration>
</plugin>

We have a multi-pom project which has a sub-project that wants to build a docker image.
We want to be able to call mvn dockerfile:build dockerfile:push on the parent pom and get it to build and push all docker images built in the child poms.
Here is the solution we came up with.
This allows us at the top level of the pom call mvn dockerfile:build to build all our children docker images, and at our top level mvn dockerfile.skip=true deploy will skip generating docker images in the deploy phase.