Enjoy trying out all the cool new features like builtin synchronous replication or per-column collation settings for correctly handling international strings, or an even finer-grained access control for large environments. Please see the detailled explanation of the new features.

As already announced a few days ago, 9.0 is gone from Ubuntu 11.10, as it is still only a development version and not an LTS. 9.1 will be the version which the next 12.04 LTS will support, so this slightly reduces the number of major upgrades Ubuntu users will need to do. However, 9.0 will still be available in Debian unstable and backports, and the Ubuntu backports PPA for a couple of months to give DB administrators some time to migrate.

We always strive to minimize the number of major versions which we have to support. They not only mean more maintenance for developers, but also more upgrade cycles for the users.

9.0 has not been in any stable Debian or Ubuntu release, and 9.1 final will be released soon. So we recently updated the current Ubuntu development release for 11.10 (“oneiric”) to 9.1. In Debian, the migration from 8.4/9.0 to 9.1 is making good progress, and there is not much which is left until postgresql-9.0 can be removed.

Consequently, I also removed 9.0 from my PostgreSQL backports PPA, as there is nothing any more to backport it from. However, that mostly means that people will now set up installations with 9.1 instead of 9.0, and won’t magically make your already installed 9.0 packages go away. They will just be marked as obsolete in the postgresql-common debconf note.

If you want to build future 9.0 packages yourself, you can do this based on the current branch: bzr branch lp:~pitti/postgresql/debian-9.0, get a the new upstream tarball, name it accordingly, add a new changelog with a new upstream version number, and run bzr bd to build the package (you need to install the bzr-builddeb package for this).

Update 2011-09-09: As I got a ton of pleas to continue the 9.0 backports for a couple of months, and to keep it in Debian unstable for a while longer, I put them back now. I also updated the removal request in Debian to point out that I’m mainly interested in getting 9.0 out of testing. I don’t mind much maintaining it for a couple of more months in unstable. My dear, I had no idea that my backports PPA was that popular!

Warning for upgrades from Beta 1: The on-disk database format changed since Beta-1. So if you already have the beta-1 packages installed, you need to pg_dumpall your 9.1 clusters (if you still need them), and pg_dropcluster all 9.1 clusters before the upgrade. I added a check to the pre-install script to make the postgresql-9.1 package fail early to upgrade if you still have existing 9.1 clusters to avoid data loss.

Due to my recent moving and the Ubuntu Developer Summit it took me a bit to package them for Debian and Ubuntu, but here they are at last. I uploaded postgresql-9.1 to Debian experimental; currently they are sitting in the NEW queue, but I’m sure our restless Debian archive admins will get to it in a few days. I also provided builds for Ubuntu 10.04 LTS, 10.10. and 11.04 in my PostgreSQL backports for stable Ubuntu releases PPA.

I provided full postgresql-common integration, i. e. you can use all the usual tools like pg_createcluster, pg_upgradecluster etc. to install 9.1 side by side with your 8.4/9.0 instances, attempt an upgrade of your existing instances to 9.1 without endangering the running clusters, etc. Fortunately this time there were no deprecated configuration options, so pg_upgradecluster does not actually have to touch your postgresql.conf for the 9.0 →9.1 upgrade.

They pass upstream’s and postgresql-common’s integration test suite, so should be reasonably working. But please let me know about everything that doesn’t, so that we can get them in perfect shape in time for the final release.

I anticipate that 9.1 will be the default (and only supported) version in the next Debian release (wheezy), and will most likely be the one shipped in the next Ubuntu LTS (in 12.04). It might be that the next Ubuntu release 11.10 will still ship with 9.0, but that pretty much depends on how many extensions get ported to 9.1 by feature freeze.

It would be great if you could add package name info for Fedora/SUSE/etc., and perhaps add more example links for porting different kinds of software! Please also let me know if you have suggestions how to improve the structure of the page.

The topic that kept me busy most in this cycle was Python gobject-introspection, and porting pygtk2 apps to PyGI (see my initial steps and my report from the PyGI hackfest.)

To spread the love, there will be two talks about this next week: On Monday 17:00 UTC the very Tomeu Vizoso himself will explain what gobject-introspection (“GI”) is, why we need it, and how library developers use it to ship a good and useful GI binding (“typelib”) for application developers. I will then follow up on Tuesday 16:00 UTC about the app developer side, in particular how to use the GI typelibs in Python, and how to port PyGTK2 applications to PyGI.

For the most part these sessions are distribution neutral (we don’t have any special sauce for this in Debian/Ubuntu, it all happened right upstream ); only a very small fraction of it (where I explain package names, etc.) will be specific to Debian/Ubuntu, but shouldn’t be hard to apply to other distributions as well.

So please feel invited to join, and bombard us with questions!

Last week I was in Prague to attend the GNOME/Python 2011 Hackfest for gobject-introspection, to which Tomeu Vizoso kindly invited me after I started working with PyGI some months ago. It happened at a place called brmlab which was quite the right environment for a bunch of 9 hackers: Some comfy couches and chairs, soldering irons, lots of old TV tubes, chips, and other electronics, a big Pirate flag, really good Wifi, plenty of Club Mate and Coke supplies, and not putting unnecessary effort into mundane things like wallpapers.

It was really nice to get to know the upstream experts John (J5) Palmieri and Tomeu Vizoso (check out Tomeu’s blog post for his summary and some really nice photos). When sitting together in a room, fully focussing on this area for a full week, it’s so much easier to just ask them about something and getting things done and into upstream than on IRC or bugzilla, where you don’t know each other personally. I certainly learned a lot this week (and not only how great Czech beer tastes )!

So what did I do?

Application porting

After already having ported four Ubuntu PyGTK applications to GI before (apport, jockey, aptdaemon, and language-selector),
my main goal and occupation during this week was to start porting a bigger PyGTK application. I picked system-config-printer, as it’s two magnitudes bigger than the previous projects, exercises quite a lot more of the GTK GI bindings, and thus also exposes a lot more GTK annotation and pygobject bugs. This resulted in a new pygi s-c-p branch which has the first 100 rounds of “test, break, fix” iterations. It now at least starts, and you can do a number of things with it, but a lot of functionality is still broken.

As a kind of “finger exercise” and also to check for how well pygi-convert works for small projects now, I also ported computer-janitor. This went really well (I had it working after about 30 minutes), and also led me to finally fixing the unicode vs. str mess for GtkTreeView that you got so far with Python 2.x.

pygobject and GTK fixes

Porting system-config-printer and computer-janitor uncovered a lot of opportunities to improve pygi-convert.sh, a big “perl -e” kind of script to do the mechanical grunt work of the porting process. It doesn’t fix up changed signatures (such as adding missing arguments which were default arguments in PyGTK, or the ubiquitous “user_data” argument for signal handlers), but at least it gets a lot of namespaces, method, and constant names right.

I also fixed three annotation fixes in GTK+. We also collaboratively reviewed and tested Pavel’s annotation branch which helped to fix tons of problems, especially after Steve Frécinaux’s excellent reference leak fix, so if you play around with current pygobject git head, you really also have to use the current GTK+ git head.

Speaking of which, if you want to port applications and always stay on top of the pygobject/GTK development without having to clutter your package system with “make install”s of those, it works very well to have this in your ~/.bashrc:

export GI_TYPELIB_PATH=$HOME/projects/gtk/gtk:$HOME/projects/gtk/gdk
export PYTHONPATH=$HOME/projects/pygobject

Better GVariant/GDBus support

The GNOME world is moving from the old dbus-glib python bindings to GDBus, which is integrated into GLib. However, dbus-python exposed a really nice and convenient way of doing D-Bus calls, while using GDBus from Python was hideously complicated, especially for nontrivial arguments with empty or nested arrays:

from gi.repository import Gio, GLib
from gi._gi import variant_type_from_string

d = Gio.bus_get_sync(Gio.BusType.SESSION, None)
notify = Gio.DBusProxy.new_sync(d, 0, None, 'org.freedesktop.Notifications',
    '/org/freedesktop/Notifications', 'org.freedesktop.Notifications', None)

vb = GLib.VariantBuilder()
vb.init(variant_type_from_string('r'))
vb.add_value(GLib.Variant('s', 'test'))
vb.add_value(GLib.Variant('u', 1))
vb.add_value(GLib.Variant('s', 'gtk-ok'))
vb.add_value(GLib.Variant('s', 'Hello World!'))
vb.add_value(GLib.Variant('s', 'Subtext'))
# add an empty array
eavb = GLib.VariantBuilder()
eavb.init(variant_type_from_string('as'))
vb.add_value(eavb.end())
# add an empty dict
eavb = GLib.VariantBuilder()
eavb.init(variant_type_from_string('a{sv}'))
vb.add_value(eavb.end())
vb.add_value(GLib.Variant('i', 10000))
args = vb.end()

result = notify.call_sync('Notify', args, 0, -1, None)
id = result.get_child_value(0).get_uint32()
print id

So I went to making the GLib.Variant constructor work properly with nested types and boxed variants, adding Pythonic GVariant iterators and indexing (so that you can treat GVariant dictionaries/arrays/tuples just like their Python equivalents), and finally a Variant.unpack() method for converting the return value of a D-Bus call back into a native Python data type. This looks a lot friendlier now:

from gi.repository import Gio, GLib

d = Gio.bus_get_sync(Gio.BusType.SESSION, None)
notify = Gio.DBusProxy.new_sync(d, 0, None, 'org.freedesktop.Notifications',
    '/org/freedesktop/Notifications', 'org.freedesktop.Notifications', None)

args = GLib.Variant('(susssasa{sv}i)', ('test', 1, 'gtk-ok', 'Hello World!',
    'Subtext', [], {}, 10000))
result = notify.call_sync('Notify', args, 0, -1, None)
id = result.unpack()[0]
print id

I also prepared another patch in GNOME#640181 which will provide the icing on the cake, i. e. handle the variant building/unpacking transparently and make the explicit call_sync() unnecessary:

from gi.repository import Gio, GLib

d = Gio.bus_get_sync(Gio.BusType.SESSION, None)
notify = Gio.DBusProxy.new_sync(d, 0, None, 'org.freedesktop.Notifications',
    '/org/freedesktop/Notifications', 'org.freedesktop.Notifications', None)

result = notify.Notify('(susssasa{sv}i)', 'test', 1, 'gtk-ok', 'Hello World!',
            'Subtext', [], {}, 10000)
print result[0]

I hope that I can get this reviewed and land this soon.

Thanks to our sponsors!

Many thanks to the GNOME Foundation and Collabora for sponsoring this event!

Hot off the press, I uploaded postgresql-9.0 final into Debian unstable; they will not go into Debian Squeeze, because Squeeze is frozen and it will take a long time to port all the packaged server side extensions to 9.0.

If you are on Ubuntu 10.04 LTS or Ubuntu 10.10, you can add my PostgreSQL backports for stable Ubuntu releases PPA, which will carry 9.0 until it can be moved to the official Ubuntu backports (i. e. when 9.0 goes into Ubuntu Natty).

Enjoy, and kudos to the PostgreSQL team!

Distribution Packaging and Maintenance

My first sponsored Debian upload ever was cracklib2, which seriously needed some love and was looking for a new maintainer. So in that upload I managed to close all outstanding bugs. Thanks to my mentor Martin Godisch about providing a lot of guidance for this!

Since then I’ve maintained various packages, where the most popular ones are certainly the free database server “PostgreSQL” (see next section) and the e-book management software “Calibre”.

“Maintaining” by and large means “making it really easy to get and use this software”. This decomposes to:

• Packaging it in a way that a simple apt-get install makes the software work out of the box (as far as possible)
• Provide a default configuration/customizations so that it integrates and plays well with the rest of the system; this includes the paths and permissions for log files, log rotation, debconf, configuration file standards, etc.
• Be the front line for bug reports from users, sort, answer, and de-duplicate them, and either fix them myself, or forward useful bugs to upstream.
• Providing security updates for stable releases
• To some extent, help with the development of the software; this gets mostly driven by user demand, and of course my personal interests.

In August 2004 I got employed by Canonical to work full time on Ubuntu, which pretty much turned a hobby into a profession. I never regretted this in the past years, it’s an awesome job to do!

In principle I’m doing the same thing in Ubuntu as well: Bring stuff from developers to the people out there. Except with a different focus, in Ubuntu my daily bread and butter is the GNOME desktop and stuff around (and immediately below) it. And even though after a long day of bug triaging and debugging I feel a bit low-hearted (“50.000 bugs away from perfection”), when I take a step back and see how much the usage of Free Software in the world has grown since 2004, I am very proud of being part of Ubuntu, which certainly has its fair contribution and share in this growth. So what seemed like a crazy idea from Mark back in 2004 actually has made a remarkable progress.

In the beginning of Ubuntu I mostly sent back patches to the Debian bug tracker, but this evolved quite a bit on both sides: These days I try to keep “my” packages in sync and commit stuff directly to Debian, which works very well with e. g. the pkg-utopia team, which is responsible for HAL, udisks, upower, PolicyKit, and related packages. At this point I want to thank Michael Biebl for being such an awesome guy on the Debian side! Also, it seems that Debian has moved a fair bit away from the strong “Big Maintainer Lock” towards team based maintenance, so these days it is easier than ever to commit stuff directly to Debian for a lot of packages, without much fuss.

PostgreSQL

I have done a handful of changes to PostgreSQL, but these mostly concerned easy packaging and crash fixes, nothing out of the ordinary. I’m not really a PostgreSQL upstream developer.

The thing I am really proud of is the postgresql-common package, which is a very nice example what a distro can provide on top of upstream: If you install the upstream tarball, you have to manually care for creating clusters, providing a sensible configuration for them, set up SSL, set up log rotation, etc. With postgresql-common, this is all done automatically. The biggest feature it provides is a robust and automatic way of upgrading between major releases with the pg_upgradecluster tool, which takes care of a dozen corner cases and the nontrivial process of dumping the old cluster and reloading the new one. Also, you can effortlessy run several instances of the same version in parallel, so that you can e. g. have a production and a development instance, or try the new 9.0 RC1 while still running the 8.4 production one. (more details)

Crash Reporting with Apport

This has been a pet peeve of mine pretty much from day 1. Back in the old days, crashes in software were a pain to track down: many crashes are hard to reproduce, it takes ages to get useful information from bug reporters, and a lot of data cannot be recovered any more when you try to reproduce and analyze a crash after the fact.

With the growing demand for QA from both Canonical and Ubuntu, in 2006 I finally got some time to start Apport, which would make all this a lot easier: It intercepts crashes as they happen, collects the data that we as a developer need, and makes it very easy for the user to submit them as a bug report. This is accompanied by a backend service (called “retracers”) which would reprocess the bug reports by taking the core dump, reproducing a chroot with the packages and versions that the reporter had, installing the debugging symbols, and re-running gdb, to produce a fully symbolic stack trace.

See this bug report for how this looks like. Since then, tons of crashes were fixed, way more than we could ever have done “the old way” with asking users to rebuild with “-g -O0″, running gdb, etc.

By today, Apport has grown quite a bit: rich bug reports, per-package hooks, automatic duplication of crashes, interactive GUI elements in hooks, etc.

Plumbing Development

Handling hotpluggable hardware has always interested me, since the day when I got my first USB stick and it was ridiculously hard (from an user perspective) to use it:

    $ su -
    # mount -t vfat -o uid=1000 /dev/sda1 /mnt

My first go at this was to write pmount which would allow normal users to mount hotpluggable storage without root privileges and worrying about mount paths and options, and then integrate it into GNOME and HAL. Personally I abandoned it years ago, but it seems other people still use it, so I’m glad that Vincent Fourmond took over the maintenance now.

Since then, the entire stack evolved quite a bit: HAL grew to something useful and rather secure, and finally into some monstrous unmaintainable beast, which is why it was declared dead in 2008, and replaced with the “U” stack: udev, udisks, upower, etc. I enjoy hacking on that a lot, and since it’s part of my Desktop Team Tech Lead/Developer role in Canonical, I can spend some company time on it. so far I worked on bug fixes, small new features, and writing a rather comprehensive test suite for udisks (see my udisks commits so far). I also did a fair share of porting stuff away from HAL to the new stack, including some permanent commitments like maintaining the keymaps in udev.

GNOME

Before I started with Canonical I was never much of a GUI person: I was fully content with fvwm and a few xterms around it. But as an Ubuntu developer I do dogfooding, and thus I switched to GNOME for my day to day work. It didn’t take long before I really fell in love with it!

Similar to my Debian packages, my upstream involvement with GNOME is mostly integration and bug fixing. As already explained, we get a looooot of bug reports, so my focus is mostly on bug fixing. To date, I sent 93 patches to bugzilla. Since January 2010 I became a committer, so that it’s easier for me to get patches upstream.

Debugging problems and fixing bugs is a pretty tedious task, but I still enjoy the rewarding nice feeling when you finally tracked down something and can close a bug with 50 duplicates, and you have made people’s life a little bit easier from now on.

As with the beta versions, I uploaded RC1 to Debian experimental again. If you want to test/use them on Ubuntu 10.04 (Lucid Lynx), you can get packages from my “PostgreSQL backports for stable Ubuntu releases” PPA. Please let me know if you need them for other releases.

Just for the records, both Debian 6.0 “Squeeze” and Ubuntu 10.10 “Maverick Meerkat” will release and officially support 8.4 only, as 9.0 is too late for the feature freezes of both. Also, it will take quite some time to update all the packaged extensions to 9.0. As usual, 9.0 will be provided as official backports for both Debian and Ubuntu.

Happy testing!