Re: [gentoo-soc] Project Grumpy - weekly report #1

[Domen Kožar]

Also, good luck with thermodynamics;)

On Tue, 2010-06-01 at 10:10 +0300, Priit Laes wrote:
> This is a weekly progress report no. 1 for Project Grumpy.
>
> As this is the first publicly visible announcement, I am also going to
> give a short overview about the project itself.
>
> The aim of this project is to create a database containing various
> developer-related metadata about packages in the Gentoo portage.
> Metadata that we are going to store can be used for different kinds of
> purposes, some examples include upstream version checks and giving
> notifications to developers who are interested about that package. And
> eventually provide a nice web and API interface to access this data.
>
> Project's semi-official IRC channel is #gentoo-grumpy on Freenode
> network. Just step in say "Hi!" :)
>
> Last week's progress report
> ===========================
>
> My first week went a bit slowly due to having some "unfinished business"
> that I needed to finish, and also because of two exams (which went
> fine).
>
> The core issue I wrestled during this week was how to keep portage
> contents and database contents in sync - ie. when ebuild is modified,
> removed or added, how to make sure that database contents correspond to
> the portage contents.
>
> The solution that I came up with is to use a simple daemon that logs
> changes to portage tree and modifies database contents when it's
> appropriate. Appropriate here means that we shouldn't log updates during
> the update of the tree as it might be unsafe (ie package rename). So
> currently it seems that daemon has also initiate the rsync progress and
> push the updates into database after rsync has finished successfully.
> (You can already see how all kinds of weird corner cases start popping
> up :P )
>
> My current approach to logging is using the inotify [1] framework
> present in Linux kernel since 2.6.13 (sorry BSD users, but this is
> Gentoo Linux afterall) with the help of pyinotify [2].
> So far there's only one drawback to using inotify - by default kernel
> has a limit of 8192 directory watches allowed per-process (but portage
> contains a lots of directories) so in order to use that approach one has
> to bump the number watches using /proc/sys/fs/inotify/max_user_watches
> tunable. 81920 has worked so far fine on my machine ;)
>
> There was also a secondary approach suggested by my mentor Leio to parse
> rsync log files, but I am a bit relucant about this idea.
>
> Anyway, I'll leave this idea simmering here for a while and unless
> someone comes up with a better idea (Yes, I have also thought about
> scanning whole portage tree every x-hours), I'm going to implement the
> daemon.
>
> Plans for current week
> ======================
>
> As I currently consider the core issue solved, the next issue I have to
> solve is how to take an ebuild, extract information about it and store
> it in database. (Hint: pkgcore)
>
> I'm not going take bigger tasks because I still have one quite hard exam
> (thermodynamics and statistical physics) on 4th of June. And if I pass,
> it is the last one.
>
> PS. Sorry, no blog yet. I was using Zine, but it broke after I updated
> my system to SQLAlchemy-0.6.
>
> [1] http://en.wikipedia.org/wiki/Inotify
> [2] http://trac.dbzteam.org/pyinotify
>
> Päikest,
> Priit Laes :)
>