Maven: Build tar.gz file with externally downloaded files - maven

Question

What I'm trying to do with maven is build a project.tar.gz file with some data in the ./data folder downloaded from some location on the web.
project.tar.gz
data
somefile.txt
some_other_file.zip
Currently I'm trying to approach this using the assembly plugin, so far without much success.
So far the following works: I download a file to target/data
But now I need that file packaged in a tar file.
<build>
<plugins>
<plugin>
<groupId>com.googlecode.maven-download-plugin</groupId>
<artifactId>download-maven-plugin</artifactId>
<version>1.2.1</version>
<executions>
<execution>
<phase>generate-resources</phase>
<goals>
<goal>wget</goal>
</goals>
<configuration>
<url>http://www.lolcats.com/images/u/08/23/lolcatsdotcomcm90ebvhwphtzqvf.jpg</url>
<outputDirectory>${project.build.directory}/data</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>

Answer 1

I ended up using https://github.com/maven-download-plugin/maven-download-plugin
<build>
<plugins>
<plugin>
<groupId>com.googlecode.maven-download-plugin</groupId>
<artifactId>download-maven-plugin</artifactId>
<version>1.2.1</version>
<executions>
<execution>
<phase>generate-resources</phase>
<goals>
<goal>wget</goal>
</goals>
<configuration>
<url>${some.jar.file.url}</url>
<outputDirectory>${project.build.directory}/lib</outputDirectory>
<url>${some.models.zip.url}</url>
<unpack>true</unpack>
<outputDirectory>${project.build.directory}/data</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.2-beta-5</version> <!-- Old -->
<executions>
<execution> <!-- Build tar.gz archive. -->
<id>tar</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
<configuration>
<descriptors>
<descriptor>src/tar.xml</descriptor>
</descriptors>
<finalName>project-${project.version}-el6</finalName>
<appendAssemblyId>false</appendAssemblyId>
</configuration>
</execution> <!-- /NewStuff -->
</executions>
</plugin>
</plugins>
</build>
using tar.xml:
<assembly>
<id>tar</id>
<formats>
<format>tar.gz</format>
</formats>
<fileSets>
<fileSet>
<directory>target/data</directory>
<outputDirectory>/data</outputDirectory>
</fileSet>
<fileSet>
<directory>target/lib</directory>
<outputDirectory>/lib</outputDirectory>
</fileSet>
<fileSet>
<directory>meta</directory>
<outputDirectory>/meta</outputDirectory>
</fileSet>
</fileSets>

Answer 2

I personally wouldn't use Maven for this; Maven is a tool for standard processes. What you want to do is very special.
Have a look at the Maven AntRun Plugin or use Ant directly. That way, you can create a script which does exactly what you want without fighting with Maven's conventions all the time.