Hi folks! We’re almost done for the official Summer of Code program and I thought that I couldn’t let it end without another update, so here we are (you may thank Daniel Burrows for additional poking). The Gtk+ interface for Aptitude is making great progress. The product is not final yet but already implements many of the planned ideas, with others to come. Here are the screenies: So, let’s see the tasks presented in my previous update:

• A real user interface <- much progress here
• Being reliable <- check! we don’t crash all the time anymore
• Packages dependencies, pre-dependencies, etc. <- check!
• Hyperlinks between packages <- check!
• Advanced package search <- check!
• Tags support (tag clouds ?) <- well, no clouds yet, but we have tags
• Linking with interesting data sources like popcon <- not done yet
• A lot of interesting things <- well..

In some more details: we are now much closer to the final interface. Some things are not done yet, for example, notification bars la Iceweasel (or is it Firefox ?) are in the works for unobtrusive notifications about important things and a little guidance. We are much more reliable now. We eliminated lots of memory management problems that resulted from, mmh, imperfect coding discipline. We also lock the interface when important backend stuff reload to prevent the user from shooting himself in the foot when triggering an install when the APT cache is reloading for example.. The backend refactoring took a sizable part of this second term but it was worth it. The code is now much cleaner and uses no more (at least much fewer) ugly unscalable hacks. One very important feature of Aptitude is the ability to easily display all kinds of dependencies and navigate through them by hyperlinking. It’s now working in the Gtk+ interface as well. Feel free to click on whatever looks like a package or a package version. We now support the powerful Aptitude package searching syntax. Daniel Burrows is talking with Enrico Zini to bring the power of apt-xapian-index to Aptitude: autocompletion! lightning fast full-text searches! tag clouds! ponies! There is still a lot to be done. I’m not going away after the GSoC program. I’m here to stay, for Aptitude and Debian. Daniel Burrows has been very helpful and supportive. The Debian community is as awesome as I knew it before participating in the program. Daniel Burrows is planning to merge the Gtk+ interface into the main branch in September and packages may appear into Experimental. With the very interesting evolutions of the upcoming Adept-3, Lenny+1 will show very interesting changes in the area of packages managers. Now for you. I need you to test my interface. All necessary instructions are on the development trac : http://dev.graffit.net/aptitude/trac.

I finally got back from Switzerland. Google invited all the Summer of Code students to visit their offices. I chose to go to the Zurich one. It wasn’t the closest (London was) but it was the largest and it had more engineers than MBAs. It has been very interesting meeting other Summer of Code participants from all Europe and a lot of other people of the free software community. There were about 40 people overall for the meeting at Google, along with free beer, cake and nice food. I gave a talk about Aptitude, how it could be useful and how I worked so far. It was nice to see that nearly a third of the audience used Debian or a derivative. By the way, the proprietary Nvidia X driver seriously messed up with the projector. It just wouldn’t detect the external display at more than 640×480, which Impress didn’t like at all. I didn’t feel like hacking around my xorg.conf while on stage so I went without the slides (well, you could see about a half of each slide actually). I heard that it was because of my old GPU (GeForce 7400) that I had poor support and the impossibility of, for example, doing RandR correctly. I had to restart X and stuff… The talk went smoothly otherwise and Google staff graced some of us with a guided visit of the 6 stories building, complete with slides, cable-cars and 18th century-themed rooms. I had to sign a NDA over whatever secrets I may see and surender my DSLR, but you can find pretty pictures in this blog post from Valleywag. The Google office really lived up to the hype. I wondered: do people actually work in there ? I guess they must do, and very well.

I’m going to the Google Europe Headquarters in Zerich, Switzerland, tomorrow (July 10th). Google is inviting us Summer of Code students, which is really nice. I should be there in the middle of the afternoon from Paris. I’ll be wearing a Slashdot tshirt. Drop me a mail or a comment if you go too so we can meet!

New status update! Here’s what Aptitude looks like: (more screenshots after the break) I’ve been exploring how the APT libraries work and how to interact with the aptitude back-end and here’s what it can do now:

• Update package lists
• Display package lists
• Basic package search
• Mark packages for install/remove/purge/keep/hold
• Display package actions for execution
• Display conflicts
• Display and navigate between package conflict solutions
• Apply them
• Execute package actions (ie. actually install stuff)

What’s missing:

• A real user interface
• Being reliable…
• Packages dependencies, pre-dependencies, etc.
• Hyperlinks between packages
• Advanced package search
• Tags support (tag clouds ?)
• Linking with interesting data sources like popcon
• A lot of interesting things

Basic functions of a package manager are already covered. We’re still at the APT API exploration phase although we’re almost done with it. I will soon start working on the final user interface and the real code design. The current code is about 2000 lines of hastily hacked together C++ and XML. I’ll have to restart the coding with a more elaborate Object design. Something that will be easier to work with in the future. The code is on http://dev.graffit.net/aptitude/trac. You can try to compile it and play with it. On the other hand I’m going to scrape most of the code soon for the restart so if you’re bored.. A walkthrough and more screenshots after the break. Here’s a walkthrough of what you can do right now:

Sometimes people propose other solutions to have the Aptitude-gtk project done, like :

I d have thought that the most interesting way of doing aptitude-gtk would be to write a gtk backend for libcwidget. -Karellen

As this might be of interest to more people, I’ll repost Daniel Burrows‘ response :

Although I can see where you re coming from, a GTK+ backend to cwidget would have no significant upsides and significant downsides. The main upside to doing that from a practical point of view is that you would have only one piece of driver code for the GTK+ and curses interfaces. You wouldn t have to rewrite the entire interface from scratch to create a GUI frontend. But this is just an illusory benefit. cwidget is a terminal interface library and aptitude s curses frontend is a terminal-based UI. From a practical point of view, this means that aptitude regularly assumes that, for instance, to clear out a line it s sufficient to output $WIDTH space characters (ASCII 32) with the desired background style. A port of cwidget to GTK+ would have to introduce new, interface-independent abstractions for all operations like this and eliminate all direct use of terminal-based assumptions, at a significant cost in complexity for both cwidget and the aptitude frontend. In order to transition to these new conventions, I believe you would have to rewrite large portions of both cwidget *and* aptitude in order to make the interface abstraction layer work. (remember: the justification for doing this is to avoid having to rewrite aptitude!) Furthermore, while this approach avoids reimplementing aptitude s curses interface (sort of, except where it doesn t see above), it does so at the cost of requiring you to reimplement all of cwidget, for GTK+. I just did a quick line count (with wc -l ): in all of cwidget there are 23,390 lines of code, while aptitude s curses frontend has around 23,359 lines of code (some of which are actually shared with the other frontends but are in the curses directory due to the historical organization of the code tree). Not only is a rewrite of cwidget more involved, but the amount of code you d have to replace is comparable to the amount implicated in a rewrite of aptitude itself! Finally, even if these costs weren t enough to eliminate the idea, it s not at all clear to me that a GTK+ backend for cwidget is even desirable. Although aptitude has some superficial similarities to a GUI program, the process of designing an interface to run in a terminal (where the available input mechanisms are relatively restricted and all output is to a character-cell grid) is rather different from the process of designing a GUI. GUI programs can t rely on some simplifying assumptions that terminal programs can, and at the same time they have a lot more options available to them (just to name a few: graphics, multiple windows, differing text sizes and rotated text). Trying to force everything through an abstraction designed for terminal output would require you to either

1. eschew those options,
2. provide abstract GUI components that somehow fell back to terminal rendering in a terminal, or
3. add ways for the frontend to extend the abstract widgets with custom functionality.

1. is not an option because I (and, I think, Arthur) want to design a good GTK+ package manager, not a good GTK+ imitation of a console package manager. 2. and 3. amount, in my strong opinion, to writing two separate interfaces but intertwining their implementations in a mass of maintenance-resistant and extension-resistant spaghetti code. At the end of the day, I think that having two separate frontends (sharing backend logic where appropriate, of course) is a far cleaner and more maintainable design, and also easier to create.

As I said earlier, I intend to go a little farther than just making a GTK+ “skin” over the curses interface. Think less like gvim and emacs and more like maybe ddd. I should also add that the cwidget library is used by no major programs except Aptitude so few others would benefit from a GTK+ backend. As the cwidget library homepage says:

cwidget was originally an internal user interface library for the aptitude package manager. This means, on the one hand, that cwidget is known to work in the real world for a real application; on the other hand, it means that the feature set of cwidget is coextensive with the requirements of aptitude.

I promised to post some updates about how the Aptitude project would be going so here it is. Here’s what aptitude-gtk currently looks like : Well, nothing very special right now. It’s really only a testing interface. The final GUI will probably be different. Now you may be interesting by what’s going on behind it ? Where to start ? Aptitude is written in C++ with varying dosages of OO coding depending on the age of the code :). For the most part, the code is neat, clean and easy to understand. Sometimes, it’s overengineered: the code that implements the progress status of packages downloads and actions is exhaustive enough to cover the setup phases of a hydraulic dam, although sometimes you can still see progress bars mysteriously going backwards. Sometimes, Daniel Burrows will be happy to provide you with complimentary barf bags while explaining some ungodly oddities that have existed for years because it’s easier to remember the ritual dances to do than to make stuff behave logically. Currently Aptitude-gtk is able to execute the libapt-pkg initialization phase, load up repository lists and update lists (think “aptitude update”). The next big task will be to load up the installed packages list and display it. It involves quite a lot of code because of all the things that connect to it : incremental package searches, sorts, filters and so on. It’s been very interesting so far. By the way, the minesweeper feature is already implemented, courtesy of gnomine

So I've been inexcusably tardy in announcing this, but Obey Arthur Liu is working on aptitude for Google's Summer of Code program. His goal is to write a third interface to the program, using GTK+ to produce the UI; as the abstract for his project states:

I will create a GTK+ GUI for Aptitude that will work alongside improved current ncurses and command-line interfaces. This will offer an alternative to Synaptic with an interface design geared toward usability and advanced functionality.

I'm looking forward to seeing what he comes up with! I think there are a lot of interesting possibilities in the design space of GUI package managers; hopefully he'll have time to explore at least a few of them. At the moment he's focusing on figuring out the care and feeding of the apt library backend and learning some of the quirks you have to deal with when writing a frontend against it. Arthur's blog can be found at http://www.milliways.fr and on Planet Debian. The Mercurial repository for his work can currently be found at http://dev.graffit.net/aptitude/hg/.

I was like “wtf?!”. Debian.org replaced by a link farm ? debian.org being actually domainsquatted is highly unlikely, so I started searching how this could happen. First, a little explanation of the setup :

• I’m on a bullet train on my laptop, up-to-date Debian Lenny, 2.6.24
• My laptop is connected to a 3G+ (HSDPA in the US) PDA phone with a USB cable
• The phone appears to the computer as a network interface thanks to the usb-rndis-lite kernel module
• The phone does NAT routing between my computer (192.168.0.100), himself (192.168.0.1) and a restricted network from my phone operator
• The only host visible on this restricted network is a HTTP only proxy server that checks the user agent (Nokia is OK, Firefox means GO AWAY)
• I connect through this proxy to a dedicated host through a OpenVPN tunnel masquerading as HTTP with a Nokia user agent
• The dedicated host at the other side has special iptables rules to redirect requests coming from my mobile phone operator netblock on port 80 to the regular OpenVPN port.
• The dedicated host does NAT for my computer to the real Internet.
• The total latency varies from 120ms to 30 secs and the bandwidth from 2mbps to 8kbps depending on the coverage
• The only DNS server on my laptop is set in resolv.conf to 192.168.5.1, the remote OpenVPN endpoint, the dedicated server
• The dedicated server runs Bind and provides recursive resolution

Now there are some peculiarities to the situation :

• It happens exactely once a week on the train from my home in Paris to the campus in Grenoble
• It doesn’t happen the other way around or at any other time for that matter

Some hints :

• My hostname at home is aeris.home.eu
• My hostname on campus is aeris.liuo.res.rhb
• I almost never shut down my computer, only hibernate
• Jonathan Roes

Now for the challenge : how could this happen ?

Coding and posting on a bullet train, while reading documentation on the net through a 3G wireless connection. On the laptop is a proof of concept Aptitude GTK+ demonstration.