The Old Monk

I got a new widescreen LCD for using with my Eee. Everything went on fine, but the default resolution of 1024x768 kinda sucked. The monitor (Acer AL1516W) supports a max of 1280x800, so I tried that, but I needed a custom modeline to get it working. The monitor specs say that it supports "1280x800@60Hz", but a lot of modeline generation tools don't support that odd widescreen resolution. This one does. The catch is the 60Hz - which is more like 59.91, which goes in as 59.73 in the textbox on that page. It does tell you the different values ("actually 59.91"), but you have to keep an eye. Another important thing is the monitor's 'Dot Clock' frequency. If you're exceeding that (and the tool will warn you if you are), it's most probably a mistake. Go re-read the specs of the monitor again.

FWIW, here's the modeline for the Acer AL1516W that I generated for the Eee :

"1280x800@59" 83.44 1280 1312 1624 1656 800 816 824 841

I'm writing a Perl interface to libtrackerclient (see the Tracker Project). The code will come out when it manages to do something - which should be soon, but I need a place to announce it and hold any comments that might come across. For the lack of a better option, I'd let this post be it.

Update : The code is at a stage where it's usable. The git repository is at http://repo.or.cz/w/LibTracker-Client-Perl.git. You can also grab the latest snapshot. The code is a lot of XS and some Perl. You would need libtrackerclient (and headers), glib-2.0 (and headers) and dbus-glib-1 (and headers) along with the obvious things like Perl headers and a C compiler.

There's always SCMBug, but you can cook your own Git-Bugzilla integration very easily. SCMBug's fine, but it's a lot of code if all you want is simple cross-linking between Git, Bugzilla and Trac (btw - GitPlugin for Trac would throw up an error unless you have at least *two* commits in your repository - talk about undocumented easter bugs!).

Anyhoo - here's what I want :
1. Git should disallow any commit where the commit message does not have a bug number.
2. Git should add a comment to the corresponding bug on a commit, mentioning the author, the Trac changeset link, the commit message and the list of files which changed.

And here's the code to do it. First, the post-receive hook :

#!/usr/bin/perl -w
use strict;

# A hook script which integrates with bugzilla. It looks for bug IDs in
# commit messages and adds the commit message as well as a link to the
# changeset as a comment on the bug.

# This program is released under the terms of the GNU General Public License
# version 2. A copy of the license may be obtained by emailing the author,
# or at http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt
#
# The absolute lack of warranty and other disclaimers as per the license
# apply.
#
# Copyright 2008, Devendra Gera. All rights reserved.
#
# Author : Devendra Gera 

### user configurable section

# The bugzilla has contains the server, username and password for the targeted
# bugzilla installation. There's NO 'http://' in the server line.
my $bugzilla = {
	server		=> "10.147.251.90/bugzilla",
	user		=> "demonuser",
	password	=> "daemonuserspassword",
};

# __PATH__ and __REVISION__ are replaced in $browser->{changeset} and
# $browser->{revision} to get the changeset and revision URLs respectively. 
my $browser = {
	changeset	=>
	"http://10.147.251.90/projname/changeset/__REVISION__",
	revision	=>
	"http://10.147.251.90/projname/browser/__PATH__?rev=__REVISION__",
};

# The bug_regex should extract the bug id from the commit message and place
# it in $1
my $bug_regex = 'bug #(\d+)';


##### End user configurable section

use WWW::Bugzilla;

my $input = <>;
chomp $input;

my ($oldrev, $newrev, $refname) = split /\s+/, $input;
my $commit_msg = `git-whatchanged $oldrev..$newrev`;

# prepare the changeset URL
my $changeset_url = $browser->{ changeset };
$changeset_url =~ s/__REVISION__/$newrev/g;

# author
my ($author) = ( $commit_msg =~ /^Author:\s+(.*)$/m );

# files
my @filelist = grep ( /^:/, split( /\n/, $commit_msg ) );

# prepare comment
$commit_msg =~ s/^.*?Date://s;	# eat everything till the Date: heder
$commit_msg =~ s/^.*?\n//m;	# eat the date line completely
$commit_msg =~ s/^:.*?$//mg;	# eat the file list from the msg.
chomp $commit_msg;
my ($bug_number) = ( $commit_msg =~ /$bug_regex/ );

my $comment = <<END_COMMENT;

------------------------------------
changeset $newrev [ $changeset_url ]
    by $author :

$commit_msg
------------------------------------

Files changed :
END_COMMENT

$comment .= join("", @filelist) . "\n";

my $bz = WWW::Bugzilla->new(
	server		=> $bugzilla->{ server },
	email		=> $bugzilla->{ user },
	password	=> $bugzilla->{ password },
	bug_number	=> $bug_number
);

die "cannot connect to bugzilla" unless defined $bz;

$bz->additional_comments( $comment );

$bz->commit;

And here's the update hook :

#!/usr/bin/perl -w
use strict;

my $refname = shift;
my $oldrev = shift;
my $newrev = shift;

my $commit_msg = `git-whatchanged $oldrev..$newrev`;

# check if the commit message contains a bug number
if($commit_msg !~ /bug #\d+/) {
	exit -1;
}

exit 0;

The TODO :
1. Push every configurable thing to git's config file and access it via git-config.
2. Code cleanups. One definition of the bug regex (which is hardcoded in the update for now).

edit : the here doc in the code was causing a problem with formatting, eating up some of the code. Fixed now.

WWW::Bugzilla was a great help in setting up git-bugzilla integration, but there's a small fix which needs to be applied before it would work with my Bugzilla 3 install.

The problem is that WWW::Mechanize selects the first form on a page by default, and WWW::Bugzilla fails in WWW::Mechanize while setting any field to be updated (with a 'no such field' or 'no field called comment' etc. messages). On my Bugzilla install, there's a small bug search form in the header which makes that happen.

The fix is a single line and has been emailed to the author. Here it is :

@@ -614,6 +614,7 @@
     my $mech = $self->{mech};
 
     if ($self->{bug_number}) {
+        $mech->form_name( "changeform" );
         foreach my $field ( keys %update_field_map ) {
             $mech->field( $update_field_map{$field}, $self->{$field} ) if defined($self->{$field});
             # handle special cases

There are various ways of managing multiple network profiles in Ubuntu, but I've never been a fan of NetworkManager. Commandlines work for me very well, and even there - multiple solutions exist with the help of packages like resolvconf etc. Here's my setup which is very Debian-ish and depends on this nice package called ifupdown.

First, there's the /etc/network/interfaces file :

# we always want the loopback
auto lo
iface lo inet loopback

# mappings
mapping eth0
  script /etc/network/map-scheme
  map dhcp eth0-dhcp
  map emergency eth0-emergency

mapping ath0
  script /etc/network/map-scheme
  map office ath0-office
  map home ath0-home

iface eth0-dhcp inet dhcp
  up iptables -F
  up lokkit -n -q --high --dhcp
  up /etc/init.d/lokkit restart

iface ath0-office inet dhcp
  wpa-driver madwifi
  wpa-conf /etc/wpa_supplicant/office.conf
  up iptables -F
  up lokkit -n -q --high --dhcp
  up /etc/init.d/lokkit restart

iface eth0-emergency inet static
  address 10.9.5.201
  gateway 10.9.4.1
  netmask 255.255.254.0
  up iptables -F
  up lokkit -q --high
  up echo nameserver 172.31.6.5 > /etc/resolv.conf
  up echo nameserver 203.197.12.30 >> /etc/resolv.conf

iface ath0-home inet dhcp
  wpa-driver madwifi
  wpa-conf /etc/wpa_supplicant/home.conf
  up iptables -F
  up lokkit -n -q --high --dhcp
  up /etc/init.d/lokkit restart

Notice the mappings section (and see 'man interfaces') - that allows me to say :

NETSCHEME="home" sudo ifup ath0

or

NETSCHEME="office" sudo ifup ath0

because the specified script (/etc/network/map-scheme) just looks up the NETSCHEME environment variable and spit out the correct mapping to go to. This thing, by the way, could be rigged to do arbitrarily complex tasks (look in /usr/share/doc/ifupdown/examples/ for sample scripts, including one which tries to ping some known IPs, and decides its location/profile based on successful pings - you could write one which looks for all known wireless SSIDs and then decide which profile to switch to). Here's my trivial script :

#!/usr/bin/perl -w
use strict;

my $scheme = $ENV{NETSCHEME} || "home";

while(<>) {
	if ( s/$scheme\s+// ) {
		print;
	}
}

The conf files in /etc/wpa_supplicant/* are of course wpa_supplicant configuration files. See 'man wpa_supplicant.conf' for details.

Btw, I'm taking a break. Jan 31 was my last day at work, and I haven't started looking for my next job yet. Heck, I don't even know what my next job will be like. The whole purpose of this thing is to explore certain areas and get some work done on some personal projects.