1. Debian Packages: the gory details

• • An operetta, of sorts.

2. Debian GNU/Linux

Free, community developed operating system

Always will be free because of its Social Contract and legally shielded by Software in the Public Interest

Developed by a group of about 1,000 volunteers, who receive no financial compensation

Stable

• More info in debian-history.deb

3. Development reference

Tens of thousands of packages (~25,000)

Security, package and bug tracking

Gigantic infrastructure

Serves as sort of a reference platform due to its adherence to Linux Standards Base, File Hierarchy Standard, etc.

4. Different versions

Names taken from Toy Story

Bruce Perens worked for Pixar and was Debian Project Leader at the time

Current version: etch

Next version: lenny (after that its squeeze)

Scheduled for release in 2008, but could be 2009 (currently ~100 RC bugs.)

5. What about sid?

The kid in Toy Story who broke toys

This is the unstable version of debian, and will always be unstable

Periodically testing gets frozen (like it is right now), release critical bugs get fixed, and then released as stable

So -

• Stable-> 4.0 & 4.1 code name etch

• Testing-> 5.0 code name lenny

• Unstable-> sid (Will never have a version)

6. How software gets into debian

Debian uses packages to create a modular system

The package itself is a binary format called a deb

This means it has to be built (compiled) on a packager's machine before it is uploaded to debian

A developer finds some software, not already in debian, and files an ITP (Intend To Package) bug, then closes the bug with a new deb

7. Mentoring / Sponsorship

If you have a package that you want to get into debian you can submit it tohttp://mentors.debian.net

Lots of helpful and experienced debian people to get your package in good shape for debian

8. First stop, unstable

A package gets built from source code

The packager uploads the resulting binary deb and the pristine source code into unstable (This is a bit of a gloss)

It sits in unstable for 10 days then moves to testing the package gets built on a variety of architectures

Once in testing it gets frozen and tested again before release for release critical bugs

9. How do you create a deb?

TIMTOWTDI, but debian has excellent tools:

• BTS (Bug Tracking System)

• PTS (Package Tracking System)

• • Recently moved to a new server, much more responsive.

• dh-make-perl

• dpkg

• Clean room building with pbuilder or cowbuilder

10. Closer look at the tools

BTS is widely used as a development tool, half-way to a million bugs

Bugs very often move upstream to perl, ruby, python for example

Specific types of bugs; start with RFP (Request For Packaging) to get a module into debian

File an ITP (Intend To Package) bug if you are going to package a module for debian

Filing packaging bugs is important because it prevents the duplication of work

11. Package tracking

The PTS gives you an overview of every package in debian

You can look through every debian version (i.e. stable, testing, unstable)

You can follow bug reports, and package status changes via email from the PTS and on the web

12. More PTS

PTS system has recently been updated

Hosted in Europe by 1&1

Significant traffic: 5.7 Million unique visitors (excluding robots)

122 Million hits monthly, again excluding robots

By filing an ITP bug you prevent duplicate work and confusion.

13. dh_make_perl

Powerful perl version of dh_make

Gobbles up a module from cpan (using the cpan shell)

Then builds the deb with the --build option

Lots of options and potential for customization

Calculates perl dependencies AND operating system dependencies

14. dh-makin' bacon

dh-make-perl will create the files required to build a debian source package out of a perl package.

This works for most simple packages and is also useful for getting started with packaging perl modules.

You can build and install the debian package using the --build and --install command line switches.

Using this program is no excuse for not reading the debian developer documentation, including the Debian policy, the perl policy, the packaging manual and so on.

15. Flow Source code dh-make Debian directory dpkg Deb 16. dpkg-buildpackage

dpkg is also an extremely powerful build tool. It is a set of tools really

Responsible for installing and removing packages, gets called by high-level tools like apt-get and aptitude

dpkg-buildpackage builds your deb as well as the .dsc file you need for uploading to debian

17. How does dpkg know how to build the package?

Because dh-make (alternatively dh-make-perl) built, and populated with boilerplate, the debian directory

This directory holds files and one executable, the debian/rules script

debian/rules is a Makefile which calls lots of other small debian scripts called debhelper scripts

This creates a highly modular build system with lots of opportunity for specific, small changes

18. Pbuilder and cowbuilder

Pbuilder stands for personal builder

Automatically builds debian packages in a clean-room environment

Helps to verify that a package can be built on the average debian system

It creates a base chroot image, downloads and installs a complete, but minimal, debian system

Cowbuilder is pbuilder sped up by using cowdancer, a copy-on-write system in userland

19. lintian

Lintian is the debian policy enforcer

Chatty, and pretty complete

Being lintian clean is pretty much a requirement for getting your deb into debian and definitely if you want to be a debian developer

20. What else is in the debian dir?

The debian directory also contains files which help to define the package and help in packaging.

• Copyright

• Control

• Changelog

• Watch

• Compat

21. Changelog

This required file lists all the changes

libyaml-perl (0.39-1) unstable; urgency=low

* New upstream release.

* New Maintainer with acknowledgment from Chip.

* Added the copyright statement to debian/copyright.

* Updated Standards-Version to 3.6.2.

* Moved the perl build-dep to build-dep-indep (Closes: #305525).

* Updated compat version to 4 and upgraded the debhelper dependency

accordingly.

-- Florian Ragwitz Thu,1 Dec 2005 15:33:42 +0100

22. More changelog

The recorded changes are mostly relative to the debian packaging, not the upstream source

Crucially, this is the canonical location of the package's version information

Specifies which package fixed which bug (specific syntax allows for automated bug closing from the changelog)

23. Control

Source: libpod-strip-perl

Section: perl

Priority: optional

Build-Depends: debhelper (>= 7), libmodule-build-perl

Build-Depends-Indep: perl (>= 5.6.10-12)

Maintainer: Debian Perl Group

Uploaders: Damyan Ivanov

Standards-Version: 3.8.0

Homepage: http://search.cpan.org/dist/Pod-Strip/

Vcs-Svn: svn://svn.debian.org/pkg-perl/trunk/libpod-strip-perl/

Vcs-Browser: http://svn.debian.org/wsvn/pkg-perl/trunk/libpod-strip-perl/

Package: libpod-strip-perl

Architecture: all

Depends: ${perl:Depends}, ${misc:Depends}

Description: remove POD documentation from Perl code

Pod::Strip is a subclass of Pod::Simple that removes the POD (plain old

documentation) from Perl code. The POD may optionally be replaced with

comments so that line numbers of the code stay the same.

.

Pod::Strip is useful in Perl code parsers that don't want to bother about POD.

24. Copyright

Please, please, please, included copyright and license information in your modules on CPAN.

It may not matter that much to you, it matters a lot to those who package your software for linux (at least for the Free Software distros)

It may matter a lot to you one day

It strengthens the license to have a copyright and it appears clear that the licenses DO have legal weight (the artistic license just won a big legal victory recently.)

25. Debian's copyright file

Format-Specification: http://wiki.debian.org/Proposals/CopyrightFormat?action=recall&rev=196

Upstream-Maintainer: Thomas Klausner

Upstream-Source: http://search.cpan.org/dist/Pod-Strip/

Upstream-Name: Pod-Strip

Files: *

Copyright: Copyright 2004, 2005, 2006 Thomas Klausner, All Rights Reserved.

License-Alias: Perl

License: Artistic | GPL-1+

This program is free software; you can redistribute it and/or modify it under

the same terms as Perl itself.

26. More copyright fun

Files: debian/*

Copyright: 2008, Damyan Ivanov

License: Artistic | GPL-1+

Packaging is free; you can redistribute it and/or modify it inder the same terms as Perl itself.

27. Licensing

License: Artistic

This program is free software; you can redistribute it and/or modify

it under the terms of the Artistic License, which comes with Perl.

On Debian GNU/Linux systems, the complete text of the Artistic License

can be found in /usr/share/common-licenses/Artistic

License: GPL-1+

This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 1, or (at your option)

any later version.

On Debian GNU/Linux systems, the complete text of the GNU General

Public License can be found in `/usr/share/common-licenses/GPL'

28. Watch file

# format version number, currently 3; this line is compulsory!

version=3

# URL to the package page followed by a regex to search

http://search.cpan.org/dist/Pod-Strip/.*/Pod-Strip-v?(d[d_.-]+).(?:tar(?:.gz|.bz2)?|tgz|zip)$

Allows for an automated update of source and package when there is a new version on CPAN, via the uscan tool

29. Uscan

This allows us to automatically update the package contents without having to rebuild the entire package scaffolding. $ uscan libspreadsheet-read-perl: Newer version (0.29) available on remote site:http://search.cpan.org/CPAN/authors/id/H/HM/HMBRAND/Spreadsheet-Read-0.29.tgz (local version is 0.28) libspreadsheet-read-perl: Successfully downloaded updated package Spreadsheet-Read-0.29.tgz and symlinked libspreadsheet-read-perl_0.29.orig.tar.gz to it

30. How do we know there is a new version on CPAN?

Our QA reporting tool:

http://pkg-perl.alioth.debian.org/cgi-bin/qareport.cgi

Part of the debian-perl team's workflow

Some of this functionality is moving towards CPANTS, maybe other automated debian-centric tests suites perhaps?

31. Managing packages

sudo aptitude install courier-filter-perl

Reading package lists... Done

Building dependency tree

Reading state information... Done

Reading extended state information

Initializing package states... Done

Reading task descriptions... Done

The following NEW packages will be installed:

courier-authdaemon{a} courier-authlib{a} courier-authlib-userdb{a} courier-base{a} courier-filter-perl courier-mta{a} expect{a} fam{a} libarchive-zip-perl{a} libclamav-client-perl{a} libfam0{a} libltdl3{a} libmail-spf-perl{a} libnet-rblclient-perl{a} libnetaddr-ip-perl{a} portmap{a} tcl8.4{a}

The following packages will be REMOVED:

postfix{a}

0 packages upgraded, 17 newly installed, 1 to remove and 0 not upgraded.

Need to get 4012kB of archives. After unpacking 8303kB will be used.

Do you want to continue? [Y/n/?]

32. Implications of automated packaging systems

Obsoletes debian-perl(?)

Most automated tools currently come with some form of caveat stating that there is no support, i.e. Security tracking.

Most likely quite useful if you are SURE no one else will ever use your deb

Creation of a potentially vast invisible, distributed package repository

Probably inevitable :-(

33. How to become a debian developer

Maintain packages and understand debian's Social Contract

Contribute to debian

Patience

Sponsorship

You don't need to be a DD to contribute, only tangible difference is you get a cool[email_address]and you get to vote

If you don't become a DD, you don't go MIA

The entire process is improving and becoming faster there are changes afoot (DM, DME, etc.) Potentially contreversial.

34. Resources and Thank yous

http://pkg-perl.alioth.debian.org/

Integrating perl in a wider distribution: The debian-perl group, by Gunnar Wolf

The Debian System, by Martin Krafft

dam, gregoa, gwolf, tincho, nomeata, sukria, djpig, dom, Florian R., Gabor, Jos, Nadim, joeyh, eloy, ntyni, rra, hertzog