_overview.adoc

There are two different modes how Images can be built:

Inline plugin configuration

With an inline plugin configuration all information required to build the image is contained in the plugin configuration. By default its the standard XML based configuration for the plugin but can be switched to a property based configuration syntax as described in the section External configuration. The XML configuration syntax is recommended because of its more structured and typed nature.

When using this mode, the Dockerfile is created on the fly with all instructions extracted from the configuration given.

External Dockerfile or Docker archive

Alternatively an external Dockerfile template or Docker archive can be used. This mode is switched on by using one of these three configuration options within

• dockerFileDir specifies a directory containing a Dockerfile that will be used to create the image. The name of the Dockerfile is Dockerfile by default but can be also set with the option dockerFile (see below).

• dockerFile specifies a specific Dockerfile path. The Docker build context directory is set to dockerFileDir if given. If not the directory by default is the directory in which the Dockerfile is stored.

• dockerArchive specifies a previously saved image archive to load directly. Such a tar archive can be created with docker save. If a dockerArchive is provided, no dockerFile or dockerFileDir must be given.

All paths can be either absolute or relative paths (except when both dockerFileDir and dockerFile are provided in which case dockerFile must not be absolute). A relative path is looked up in ${project.basedir}/src/main/docker by default. You can make it easily an absolute path by using ${project.basedir} in your configuration.

Any additional files located in the dockerFileDir directory will also be added to the build context as well. You can also use an assembly if specified in an assembly configuration. However you need to add the files on your own in the Dockerfile with an ADD or COPY command. The files of the assembly are stored in a build context relative directory maven/ but can be changed by changing the assembly name with the option <name> in the assembly configuration.

E.g. the files can be added with

Example

COPY maven/ /my/target/directory

so that the assembly files will end up in /my/target/directory within the container.

If this directory contains a .maven-dockerignore (or alternatively, a .maven-dockerexclude file), then it is used for excluding files for the build. Each line in this file is treated as an FileSet exclude pattern as used by the maven-assembly-plugin. It is similar to .dockerignore when using Docker but has a slightly different syntax (hence the different name).

If this directory contains a .maven-dockerinclude file, then it is used for including only those files for the build. Each line in this file is also treated as an FileSet exclude pattern as used by the maven-assembly-plugin.

Except for the assembly configuration all other configuration options are ignored for now.

For the future it is planned to introduce special keywords like DMP_ADD_ASSEMBLY which can be used in the Dockerfile template to placing the configuration resulting from the additional configuration.

The following example uses a Dockerfile in the directory src/main/docker/demo:

Example

<plugin>
 <configuration>
   <images>
     <image>
       <name>user/demo</name>
       <build>
         <dockerFileDir>demo</dockerFileDir>
       </build>
     </image>
   </images>
 </configuration>
 ...
</plugin>