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This is an edited transcript of the PPA and Ubuntu Packaging 101 session held in #launchpad at 15.00 UTC on 13th September 2007.

For details of other PPA IRC sessions, see the PPA 101 page.

Questions are left in context, unless they appear in a mass Q&A section of the session.

The original log of #launchpad for this day is available at:


Search for "Hello and welcome to the PPA and Ubuntu Packaging 101 session!"

Basics of Ubuntu packaging

Led by: Jordan Mantha - Laserjock - MOTU team

Laserjock: ok, so we don't have time to launch into a big session on packaging
Laserjock: but there are some basics that are useful when doing PPAs
Laserjock: so first off, what does PPA accept?
Laserjock: it accepts *source* packages
Laserjock: so you don't want to upload .debs

Laserjock: anybody actually read the Ubuntu Packaging Guide?
Laserjock: :-)

Various people say they have.

Laserjock: Ok, so I wanted to say that remember that we deal with source packages, that is .dsc, .diff.gz, and .orig.tar.gz normally

Laserjock: now, to start with you might find it easiest to take an existing Ubuntu package
Laserjock: you can either apt-get source <packagename>
Laserjock: and note that you shouldn't do that with sudo
Laserjock: or you can get the files from Launchpad or archive.ubuntu.com
Laserjock: you can then mess around in the unpacked source package ( dpkg-source -x <package>.dsc if it isn't unpacked already)
Laserjock: and to rebuild it you can do debuild -S (which is a wrapper around dpkg-buildpackage -S -rfakeroot)

Laserjock: if you need to include the .orig.tar.gz in the upload, like the first time you have that .orig.tar.gz in your PPA
Laserjock: then add -sa , debuild -S -sa
Laserjock: the packages need to be signed with your gpg key (the same one that's on Launchpad)
Laserjock: so make sure that the email address in your changelog entry is the same as in your gpg key
Laserjock: I would strongly suggest that people test their source package by building them locally into .debs
Laserjock: a good way to do that is with pbuilder

superm1: its much more time consuming and annoying to let the PPA fail to build than it is to do it locally
DaveMorris: for signing you can also use debsign -k<key-id> <program>_source.changes

Laserjock: superm1: exactly
Laserjock: pbuilder creates a minimal Ubuntu envioronment in a chroot

Laserjock: and and it provides a "clean room" because all the changes are dropped at then end of each session
Laserjock: I don't seem to have it on me, but I made a script that allows you to easiy create and use pbuilders
zakame: just to add: you'd want to look into /usr/lib/pbuilder/pbuilder-satisfydepends to be able to get the depencies for your package prior to building ;)
Laserjock: I'll email the launchpad-users list with a URL later
stdin: There a guide to create/use pbuilder on the wiki -> https://wiki.ubuntu.com/PbuilderHowto[[BR]] Laserjock: in any case you can have multiple pbuilders
Laserjock: one for each Ubuntu release for example
Laserjock: so you can be running Feisty and build Gutsy .debs
Laserjock: I would highly recommend testing *each* source package before you upload
Laserjock: simply as a way to minimize problems
Laserjock: with lots of packages in the build queues, etc. it can take a while to get a package into the PPA archive

tezem: Laserjock: for every Ubuntu release seperately?
Laserjock: yes

Laserjock: also note that the Packaging Guide is a community project, any help, proofreading, etc. is appreciated


Laserjock: ok, are there any parts that people had problems with specifially when it came to PPAs?

Question: damon_: what if my source code is pure python,do I need to learn all about make files and ./config etc before I can do anything useful?
Answer: Laserjock: damon_: no. python packages often use distutils. check out a similar package from the Ubuntu archive to see how they did it.

Question: superm1: well the big thing i know i ran into with PPAs off the bat was that you need to manually put the section in. which isn't addressed in that guide. since there is no override system.
Answer: cprov: superm1: but it's mentioned in PPAQuickStart. PPA don't automaticaly apply overrides, it doesn't propagate adjustments made on component/section/priority in previous uploads.
Further discussion:
superm1: cprov, indeed, but i think people might have needed a clarification on what that meant
Laserjock: I'm guessing people would find a sample debian/changelog file helpful?
cprov: superm1: yes, it definitely needs a better description then. Any suggestion ?
og3: samples are always good
cprov: Laserjock: yes, debian/{control, changelog} samples
cprov: changelog -> "bar (1.0-21) gutsy; urgency=low" and control -> "Section: universe/web" are the important bits, IMHO

Question: vinze: So is it also possible to package e.g. GTK themes?
Answer: Laserjock: it's possible to package basically anything.

Question: laga: what has caught me a few times already: the time it takes between the upload and the availability of the source packages at least. i uploaded a package to gutsy and the same package to feisty, with the orig.tar.gz this time. the second upload was reject because the orig.tar.gz was not in the archive yet.
xhaker: cprov, Laserjock: as laga pointed out, ppa requires you to upload the orig.tar.gz . Is there any plans to make ppa able to find the corresponding orig.tar.gz when it is somewhere in ubuntu.
Answer: cprov: xhaker: allowing file lookups in ubuntu archive would be helpful, we are investigating the implications in the archive, let me find the specific bug

Basics of PPA features

Led by: Celso Providelo - cprov - Launchpad team

cprov: ok, PPA UI allow users to 'retry' failed builds

Question: laga: cprov: does it also allow users to rebuild completed builds?
Answer: cprov: laga: no, only failed builds. Once a build is completed it gets published in the archive, so a 'rebuild' as this point would be a bin-NMU which is not allowed in ppas
Further discussion: geser: laga: that wouldn't be wise as this could create debs with the same name (and version) but different dependencies
cprov: laga: if you want to rebuild a completed build you have to upload a new version of the source in question

cprov: the 'retry' link is presented for PPA owners on the left-top portlet in the build page
cprov: has everyone noticed it ? is it clear to get in the build page ?

laga: tbh, i hadn't noticed it until i was told it was there
cprov: laga: but you do receive a build-failure-notification email with direct links, no ?

Question: DaveMorris: I didn't know before, but it's easy once your told, but how do you reupload the source file, the same as before?
Answer: cprov: DaveMorris: yes, just follow the established procedure

DaveMorris: my email's did't have direct links to rebuild
cprov: DaveMorris: the link points to the "build page"
DaveMorris: yeah that one is there,

cprov: where you can find out if it's a temporary failure (which could be sorted by a rebuild) or if it's permanent, like a broken source or a ogre-model failure

Question: Laserjock: cprov: if a build fails do we upload with the same versioning or do we need to bump?
Answer: cprov: Laserjock: same version would be reject ;) uploads have to use higher versions always

Question: DaveMorris: won't a revison bump make it appear as a new build though, rather than rebuilding the previous
Answer: cprov: DaveMorris: yes, new source versions will generate new builds and that's what you want. The old build records will remain as "failed".

Question: Derevko: old packages versions are marked as "PendingRemoval", when they will be removed?
Answer: cprov: Derevko: backend will be added in the next LP release cycle (in two weeks)

What is the ogre model?

Led by: Celso Providelo - cprov - Launchpad team

cprov: Ogre-model is a mechanism to force build-dependencies to be in the same or lower components
cprov: i.e., source in main can only build-depend on binaries in main, source in universe can build-depend on binaires in main, restricted, universe
cprov: currently, ogre-model failures can only be solved by another source upload

Question: mrevell: Hobbsee suggested that "ogre model" is a confusing term. Would you agree?
Answer: cprov: mrevell: we can think about another name, but that's the term used in debian and ubuntu.
Further discussion:
Hobbsee: cprov: if it's the term used in debian and ubuntu, how come most of the MOTU's dont recognise it?
superm1: Hobbsee, because its something that we normally wouldn't be exposed to since there is an override system on the archive?
cprov: Hobbsee: dunno, I didn't know it in debian either, but it's being referred like that since I implemented it two years ago
Hobbsee: cprov: the highups may know about it.
Hobbsee: superm1: depends if you ever upload to main. if you puload to main, even in ubuntu, you'll get depwaits if you build-dep on universe packages.
cprov: Hobbsee: and superm1 is right, with auto-overrides uploads almost never notice it
cprov: Hobbsee: we very rarely have uploads to main in ubuntu, they usually get promoted/overridden from universe
Hobbsee: cprov: sure, but if you upload a newer version fo what's already there, it'll land in main
Hobbsee: (if the original was in main)
cprov: Hobbsee: yes, even if the Section is "universe/<section>", that's auto-override fault.
cprov: Hobbsee: once we have UI to allow manual overrides in PPAs we can enable auto-overrides too

Question: gnomefreak: ppa is no longer beta right?
Answer: mrevell: gnomefreak: PPA is in beta but on Launchpad's production site

mrevell: Great, thanks very much both to cprov and Laserjock, and to everyone for coming! PLease post further questions to the wonderful launchpad-users list

Next session

Further PPA introductory and Q&A sessions will be held, including as part of Ubuntu Open Week in October. Please subscribe to the PPA and Ubuntu Packaging 101 wiki page to get updates.

PPA101/20070913 (last edited 2008-06-17 14:21:20 by localhost)