Thursday, March 7, 2013

Debain packaging

Stardate: 90784.6

Git-sync is a script in ruby we use at work for managing git repos. It is covered in an earlier post. I got tired of ensuring it as a file in puppet and decided to make a debian package. Here is the summary of how to make a simple debian package containing just a single file. Note that the answer to this stack overflow question is the source of most of my knowledge, so this will just be annotations and extensions to that.

Debian/Ubuntu packaging (on an ubuntu system) required me to install a single package: devscripts.

At a high level, debian packaging involves creating a 'debian' folder in your source tree and putting several metadatafiles in it. Figuring out the precise contents of these files is the challenge of packaging. I recommend you use the 'apt-get source git' command to get the source of a working package (git in this case) to compare to your own metadatafiles.

Debian/Ubuntu packaging using debuild creates files one level above your current working directory(wtf debian). So the first step is to build a build directory like:

cd ~/devel
mkdir git-sync-build
Procure the source:
nibz@darktemplar:~/devel/git-sync-build$ git clone
nibz@darktemplar:~/devel/git-sync-build$ ls
nibz@darktemplar:~/devel/git-sync-build$ cd git-sync
nibz@darktemplar:~/devel/git-sync-build/git-sync$ mkdir debian

All of the metadata files that debuild, the utility that will actually build the .deb, needs are going to be in the debian directory.

The first file to create is the debian/changelog file. This file is created with the dch utility. Run it from the git-sync directory. It will open vim and it will look like this. Many fields here need to be changed.

dch --create


  * Initial release. (Closes: #XXXXXX)

 -- Spencer Krum   Thu, 07 Mar 2013 01:40:18 -0800
PACKAGE refers to the name of the package. Replace the word PACKAGE with the name you want your package to register itself as. In my git-sync case I will use 'git-sync'. The package name must be lower case. The VERSION must be replaced with a version number. I'm using 1.0.1 for this, since it is the second release of git-sync, but the changes are very minor. There are long articles on the internet about version numbering. It's not my place to comment here. The RELEASE variable needs to be replaced with a debian or ubuntu codename such as 'precise' or 'wheezy'. I have no idea what urgency is, but setting it to low doesn't seem to hurt anything. Maybe this is how you tell apt/dpkg about security updates. The initial release stuff is fine. The name is a bit tricky. Later on we will gpg sign the package. Make sure the name and email in the changelog match exactly the name and email on your gpg key, else the debuild utility won't attempt to have you gpg sign it at all. My changelog looks like this:
git-sync (1.0.0) precise; urgency=low

  * Initial release. 

 -- Spencer Krum   Wed, 06 Mar 2013 16:46:14 -0800

Next create a debian/copyright file:
Upstream-Name: myScript
Upstream-Contact: Name, 

Files: *
Copyright: 2011, Name, 
License: (GPL-2+ | LGPL-2 | GPL-3 | whatever)
 Full text of licence.
 Unless there is a it can be found in /usr/share/common-licenses
I elected for the apache2 license and to use the two paragraph version of that license. I also gave credit where it was due here. Fill out this file as you see fit.

Next create a debain/compat file:

nibz@darktemplar:~/devel/git-sync-build/git-sync/debian$ echo 7 > compat
Next create the rules file. This file seems to be the work-doer in debian packaging. It is evaluated by make, which is picky, so make sure that indented line is a real tab(copying from my blog will probably fail). The --with python is... well I have no idea. I traced it to a python.pem (pem is a perlism) deep within /usr. Since I am packaging a ruby script I just removed it.

Example from stackoverflow

#!/usr/bin/make -f

    dh $@ --with python2
git-sync version
#!/usr/bin/make -f

	dh $@
Next make the control file. Make the natural substitutions here. I guessed on section and it just sorta worked.
nibz@darktemplar:~/devel/git-sync-build/git-sync/debian$ cat control 
Source: git-sync
Section: ruby
Priority: optional
Maintainer: Spencer Krum, 
Build-Depends: debhelper (>= 7),
               ruby (>= 1.8.7)
Standards-Version: 3.9.2
X-Ruby-Version: >= 1.8.7

Package: git-sync
Architecture: all
Section: ruby
Depends: ruby, ${misc:Depends}, ${python:Depends}
Description: Git syncing script, pull based
  Git-sync allows git repositories to be kept in sync via git
  hooks or other means. Pull based, able to handle force pushes
  and submodules
Next make the install file. I went with the default in the stackoverflow post. I attempted to make some simple modifications to it(moving the file to /usr/local/bin) and that made it fail so this file is evidently pretty finicky.
nibz@darktemplar:~/devel/git-sync-build/git-sync$ cat debian/install 
git-sync usr/bin

Now you can build the debian package.

nibz@darktemplar:~/devel/git-sync-build/git-sync$ debuild --no-tgz-check
If all went well, it should ask you to decrypt your gpg key twice and build a package in the directory one level up.
nibz@darktemplar:~/devel/git-sync-build/git-sync$ ls ..
git-sync          git-sync_1.0.0.dsc
git-sync_1.0.0_all.deb  git-sync_1.0.0_amd64.changes  git-sync_1.0.0.tar.gz
You now have a shiny .deb file that can be installed with dpkg -i git-sync_1.0.0_all.deb

It is easy to put this in a launchpad PPA if you have a launchpad account. From your launchpad homepage (a shortcut is if you are signed in). Press the "Create new PPA". Fill out the form.

Next build a source package. Launchpad PPAs take source packages and build binary packages on launchpad servers. Build it with:

nibz@darktemplar:~/devel/git-sync-build/git-sync$ debuild -S
It should go through the gpg motions again and build a source file. Then you should be able to run something like(with your launchpad username and name of PPA):
dput ppa:krum-spencer/git-sync-ppa git-sync_1.0.0_source.changes

Happy Packaging!

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