Question: how to use maven resource filtering?

Hello,

Let me say it’s a great project and it’s a real pleasure to use in our development life cycle.

However, I’m having a hard time with one particular use case. I’m not particular sure whether it’s the right place to ask question. Please forward me to right place if it is not.

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The question: How does one use properly maven resource filtering capability? I’ve found mentioning of assembly filter flag in some other issues. I’ve tried, but I kinda failed / didn’t like the result.

Let me explain my use case first:

• I have Docker file ADD-ing some configuration file from src/main/docker
• That particular file contains artifactId and artifact version.
• I would like to have that information to be provided / injected by maven resource filtering.

What I’ve tried:

• Assembly <fileSet>, which took the original file and placed it somewhere at target/docker/registry-xyz.com/artifact/0.0.1-SNAPSHOT/build/maven/home/username/path1/path2/target/docker/registry-xyz.com/artifact/0.0.1-SNAPSHOT/build/maven/MY_FILE

I’m struggling to find the proper workaround and come up with concise and clear configuration snippet to get it done.

Any suggestions, maybe some links to examples or documentation etc … I would really appreciate that…

[alan-czajkowski]

Hi @leonardinius @vberruchon,

below is my answer (similar to @chris-snider):

First, let’s make sure our plugin versions are properly defined in the <pluginManagement> section:

  <build>

    ...

    <pluginManagement>

      <plugins>

        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-resources-plugin</artifactId>
          <version>2.7</version>
          <configuration>
            <encoding>UTF-8</encoding>
          </configuration>
        </plugin>

        <plugin>
          <groupId>org.jolokia</groupId>
          <artifactId>docker-maven-plugin</artifactId>
          <version>0.13.7</version>
          <configuration>
            <verbose>true</verbose>
          </configuration>
        </plugin>

      </plugins>

    </pluginManagement>

    ...

  </build>

Step 1: setup maven-resources-plugin:

      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-resources-plugin</artifactId>
        <executions>
          <execution>
            <id>filter-dockerfiles</id>
            <phase>process-resources</phase>
            <goals>
              <goal>copy-resources</goal>
            </goals>
            <configuration>
              <resources>
                <!-- # Filtered Resources -->
                <resource>
                  <directory>${project.basedir}/src/main/docker</directory>
                  <filtering>true</filtering>
                  <includes>
                    <include>Dockerfile</include>
                  </includes>
                </resource>
                <!-- # Unfiltered Resources -->
                <resource>
                  <directory>${project.basedir}/src/main/docker</directory>
                  <filtering>false</filtering>
                  <excludes>
                    <exclude>Dockerfile</exclude>
                  </excludes>
                </resource>
              </resources>
              <outputDirectory>${project.build.directory}/docker</outputDirectory>
            </configuration>
          </execution>
        </executions>
      </plugin>

Note: the <outputDirectory>${project.build.directory}/docker</outputDirectory> is important for 2 reasons a) when you do custom resource filtering you should always send the filtered (modified) resource to the build output directory (${project.build.directory}) as good practice, and b) this acts as the Dockerfile input for the Docker maven plugin below

Step 2: setup docker-maven-plugin:

      <plugin>
        <groupId>org.jolokia</groupId>
        <artifactId>docker-maven-plugin</artifactId>
        <configuration>
          <images>
            <image>
              <name>${docker.image.name}:${project.version}</name>
              <alias>${project.artifactId}</alias>
              <build>
                <assembly>
                  <dockerFileDir>${project.build.directory}/docker</dockerFileDir>
                </assembly>
              </build>
            </image>
          </images>
        </configuration>
        <executions>
          <execution>
            <id>build-docker-image</id>
            <goals>
              <goal>build</goal>
            </goals>
            <phase>package</phase>
          </execution>
          <execution>
            <id>push-docker-image</id>
            <goals>
              <goal>push</goal>
            </goals>
            <phase>deploy</phase>
          </execution>
        </executions>
      </plugin>

You can now add Maven variable interpolation ${...} inside your src/main/docker/Dockerfile, for example I do something like:

FROM ${docker.repo}/${docker.groupId}/base:${project.version}
MAINTAINER ${docker.maintainer}
...

using properties such as:

  <properties>
    <docker.repo>docker.example.com</docker.repo>
    <docker.groupId>example</docker.groupId>
    <docker.artifactId>${project.artifactId}</docker.artifactId>
    <docker.image.name>${docker.repo}/${docker.groupId}/${docker.artifactId}</docker.image.name>
    <docker.maintainer>"Example Engineering" &lt;[e-mail]&gt;</docker.maintainer>
  </properties>

[jakub-bochenski]

Setting <dockerFileDir>${project.build.directory}/docker</dockerFileDir> makes my build fail with Execution docker of goal io.fabric8:docker-maven-plugin:0.15.16:build failed: A tar file cannot include itself. probbably beacuse it causes the docker-build.tar to reference itself. When I open the tar it has a Dockerfile at root, a maven directory, and a directory structure corresponding to the docker repository with tmp, build and work folders.