Simplify configuration

[rhuss]

When only a single image should be build with a Dockerfile, the current configuration syntax has too much boilerplate.

E.g.

<plugin>
  <groupId>io.fabric8</groupId>
  <artifactId>docker-maven-plugin</artifactId>        
  <configuration>
    <images>
      <image>
        <name>${project.groupId}/${project.artifactId}:${project.version}</name>
        <build>
          <dockerFile>Dockerfile</dockerFile>
        </build>
      <image>
    </images>
  </configuration>
</plugin>

should be possible with

<plugin>
  <groupId>io.fabric8</groupId>
  <artifactId>docker-maven-plugin</artifactId>        
</plugin>

when a single Dockerfile in the base directory (or src/main/docker). The image name defaults to ${project.groupId}/${project.artifactId}:${project.version} then, but can be configured with a global imageName.

Also think about a compatibility mode for the configuration syntax of https://github.com/spotify/docker-maven-plugin or https://github.com/spotify/dockerfile-maven

[rohanKanojia]

Hi @rhuss ,
I would like to work on this. Could you please give me code pointers related to this?

[rhuss]

@rohanKanojia awesome, thanks ;-)

A good starting point is the class ImageConfiguration and how it is used in BuildMojo.executeInternal(). I would add a check, whether the ImageConfiguration is empty and then build up one dynamically with the given defaults (and when a Dockerfile exists in either src/main/docker or top-level in the project dir).