gjp – builds RPMs for Java software

gjp is a set of tools to help you build RPM packages for Java projects.

Packaging of Java projects is sometimes hard because build tools like Maven partially overlap with distro tools like RPM in functionality.

We are trying to come up with a tool that drastically simplifies packaging.

Installation

You need:

  • Ruby 1.9;
  • git;
  • a JDK that can compile whatever software you need to package;

Install gjp via RubyGems:

 gem install gjp

Workflow

Building a package with gjp is quite unusual — this is a deliberate choice, so don't worry. Basic steps are:

  • gjp init a new project;
  • add sources to src/<package name> and anything else needed for the build in kit/ in binary form (typically a copy of Maven and maybe some other dependency jars);
  • execute gjp dry-run, then any command needed to compile your software, then gjp finish;
  • execute gjp generate-all: gjp will look at changed files and Bash history to scaffold spec files and tarballs.

Done!

How can that possibly work?

With gjp you are not building all dependencies from source, just your package. Everything else is shipped already compiled with attached source files, which is much easier to implement and automate. Yet, it is sufficient to fulfill open source licenses and to have a repeatable, networkless build. See MOTIVATION.md for further information.

A commons-collections walkthrough

First, ceate a new gjp project, in this example named "myproject":

mkdir myproject
cd myproject
gjp init

Second, place commons-collections source files in the src/ folder. Specifically, every src/ subfolder will become a separate package named after the folder itself, so you can use the following:

cd src
mkdir commons-collections
cd commons-collections
wget http://archive.apache.org/dist/commons/collections/source/commons-collections-3.2.1-src.zip
unzip commons-collections-3.2.1-src.zip
rm commons-collections-3.2.1-src.zip

Third, put all non-source files needed for the build in kit/. This means all build dependencies and tools excluding the JDK: in this case it is just Maven:

cd ../../kit
wget http://www.eu.apache.org/dist/maven/binaries/apache-maven-3.1.1-bin.zip
unzip apache-maven-3.1.1-bin.zip
rm apache-maven-3.1.1-bin.zip

Fourth, you need to show gjp how to build your package by running appropriate commands between gjp dry-run and gjp finish. Bash history will be recorded to generate a "starting-point" build script (that will be sufficient in simple cases like this):

cd ../src/commons-collections/commons-collections-3.2.1-src/
gjp dry-run
gjp mvn package
gjp finish

Note that we used gjp mvn package instead of mvn package: this will use of the Maven copy we put in kit/ and the repository in kit/m2. Also note that this being a dry-run build, sources will be brought back to their original state after gjp finish, as this ensures build repeatability.

Finally, generate build scripts, spec files and tarballs in the output/ directory:

gjp generate-all

Note that gjp will generate files for the commons-collections package and for the binary-only myproject-kit package, which is a special container of all build-time dependencies (basically, the kit/ folder). This will be shared among all packages you might add to your gjp project.

In-depth information

In more complex cases building a package will require some special tweaks. We are trying to cover the most common in the SPECIAL_CASES.md file.

An in-depth discussion of this project's motivation is available in the MOTIVATION.md file.

Status

gjp is a research project currently in beta state. If you are a packager you can try to use it, any feedback would be very welcome!

At the moment gjp is tested on openSUSE.

Sources

gjp's Git repo is available on GitHub, which can be browsed at:

https://github.com/SilvioMoioli/gjp

and cloned with:

git clone git@github.com:SilvioMoioli/gjp.git

Contact

Are you using gjp or even just reading this? Let's get in touch!

smoioli at suse dot de

License

MIT license.