Using Maven Build Tools

Table of Contents

1. Installing Maven
2. Running Maven
3. Directory structure to use with Maven
4. Using Maven to build an NCM component
   1. Creating the basic structure for the component
   2. Importing an existing component into the new structure
5. Actually building the software
6. Open questions

Maven is a Java-based system that provides a standard file format for build information, well-defined build lifecycle, and plugin framework for extensions. There also exist standard repositories in which both development and production packages (artifacts) can be maintained. The maven plugins are also available through standard maven repositories, allowing the core maven code to be very small. Any real build, however, will require a large number of additional plug-ins that are downloaded automatically and cached on the user's machine.

Installing Maven

To download and install maven see the ​maven website.

Essentially the only required dependency is a recent, certified version of a Java Virtual Machine. This installation provides a command line interface to maven, the primary command being mvn.

Maven also integrates well with Eclipse. The ​m2eclipse plugin is recommended.

Running Maven

Running maven should be as simple as checking out the Quattor code and then running mvn package. This will prepare the sources, compile them (if necessary), and package the results. If on a machine which supports RPM packaging, RPM packages will be produced. In all cases, appropriate tarballs will be generated.

Directory structure to use with Maven

Quattor modules that should be built with Maven will have the following structure:

• ChangeLog
• pom.xml (project file)
• src
  • main
    • pan
      • components
        • <component name>
      • config.pan: What users will tipically include from their profiles. Everything else is included directly or indirectly from here.
      • schema.pan: Component's schema
      • config-common.pan: Component's basic configuration. Usually it doesn't need any human edition. But if you need any extra files, include them here.
      • config-rpm.pan: Installs the component's RPM.
      • config-xml.pan: If you don't want an RPM, but prefer to ship the component's code directly in its profile.

• perl
  • <component name>.pm: Code
  • <component name>.pod: Documentation.

Please note that there are no ".cin" files anymore. Files are not renamed anymore with the new build tools.

Using Maven to build an NCM component

Add the LAPP nexus repository to your ~/.m2/settings.xml file. An example looks like this:

<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0
                      http://maven.apache.org/xsd/settings-1.0.0.xsd">
  <localRepository/>
  <interactiveMode/>
  <usePluginRegistry/>
  <offline/>
  <pluginGroups/>
  <servers/>
  <mirrors/>
  <proxies/>
  <profiles>
    <profile>
      <id>quattor-plugins</id>
      <pluginRepositories>
        <pluginRepository>
          <id>quattor-releases</id>
          <url>http://lapp-repo01.in2p3.fr:8081/nexus/content/repositories/releases/</url>
        </pluginRepository>
      </pluginRepositories>
    </profile>    
  </profiles>
  <activeProfiles/>
</settings>

Creating the basic structure for the component

You'll get the basic directory structure for the component with:

mvn archetype:generate \
    -DarchetypeArtifactId=cfg-module \
    -DarchetypeGroupId=org.quattor.maven \
    -DarchetypeVersion=1.3 \
    -DarchetypeRepository=http://lapp-repo01.in2p3.fr:8081/nexus/content/repositories/releases/

With all this, you can now write your code!

Importing an existing component into the new structure

First of all, go to the old structure, with the old build tools and run make there. It will expand all placeholders, and you'll get the files you really want to import.

Next, remove all those heavy headers we used to have. Instead, the following, lighter header:

# ${license-info}
# ${developer-info}
# ${author-info}
# ${build-info}

will give the same information, and will get expanded by Maven.

Now, copy the generated files into the correct places. Perl and pode code are obvious. Then, your old config.tpl should become your new config-common.pan, and your old schema.tpl should become your new schema.pan.

And that's it. You can add the new hierarchy to SVN and get rid of the old one. :)

Actually building the software

To build it, you just need to be on the top level directory, and run:

mvn -P quattor-plugins clean package 

It will ask a number of questions. If you want it to be completely interactive, you can run it with -batch.

Now, all your files (tarballs, RPMs, whatever) are in the target subdirectory.

Open questions

(LF) How is tagging done?

(Cal) This is an open question. At the moment only someone with access to the Quattor nexus server can do a full release of something. Either we need to give this right to everyone, or rely on a continuous integration server to do it for us. I prefer the second option, but it needs to be discussed at the workshop.

Follow-up on ticket #225