gconftool-2 in Intrepid not working from cron

[mike2357]

Binary package hint: gconf

In Hardy and prior versions, I used cron to call a script to change my screen background. In Intrepid, these commands do not work from cron, although they do work from the command line. For some reason, gconftool-2 is not attaching to my session. The script is executing fine and produces output, it's just that the gconftool-2 commands don't have any effect.

Commands:
gconftool-2 -t str --set /desktop/gnome/background/picture_filename "$picture_name"
gconftool-2 -t str --set /desktop/gnome/background/picture_options "stretched"

Clue:
When the script it run from cron, the following command gives an exit status of 2, which means gconfd is not running. When run from the command line, it gives an exit status of 0, wihch means gconfd is running.
gconftool-2 --ping

ProblemType: Bug
Architecture: i386
DistroRelease: Ubuntu 8.10
Package: gconf2 2.24.0-0ubuntu1
ProcEnviron:
 PATH=/home/username/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gconf
Uname: Linux 2.6.27-7-generic i686

[gnudoc (gnudoc)]

I get exactly the same result.
Some background discussion at http://ubuntuforums.org/showthread.php?t=952452

[Sebastien Bacher (seb128)]

thank you for your bug report, that's not a bug though gconf just uses dbus now so it needs a session bus running, you can run the command using dbus-launch which should work correctly

[Loïc Minier (lool)]

This is related to the move of gconf from corba to DBus.

Because gconf is now over the session dbus, you can't talk to it from cron.

There's a way around this, which is to locate one process running in your dbus session and reading the "DBUS_SESSION_BUS_ADDRESS" env var from it; for instance:
xargs -n 1 -0 echo </proc/$(pidof x-session-manager)/environ | grep -Z DBUS_SESSION_BUS_ADDRESS=

[mike2357 (mike2357)]

Thanks for the advice. I was able to capture DBUS_SESSION_BUS_ADDRESS. Now what do I do with it so I can call gconftool-2 from cron?

[Loïc Minier (lool)]

On Sun, Oct 19, 2008, mike2357 wrote:
> Thanks for the advice. I was able to capture DBUS_SESSION_BUS_ADDRESS.
> Now what do I do with it so I can call gconftool-2 from cron?

 You set it in the env of gconftool-2.

--
Loïc Minier

[kraftb (kraftb)]

Hi !

I think it is easier to get the DBUS_SESSION_BUS_ADDRESS from:

/home/myUser/.dbus/session-bus/

In this directory you find a list of files for each dbus (gnome?) session ...
You could either simply "source" it or otherwise add the variables in there to your environment.

[Thierry Daucourt (thierry-daucourt)]

adding the line below, inside the script that is launched by cron, solved my problem:

export $(xargs -n 1 -0 echo </proc/$(pidof x-session-manager)/environ | grep -Z DBUS_SESSION_BUS_ADDRESS=)

[Loïc Minier (lool)]

The best thing to do in your crons is to source the correct file in ~/.dbus/session-bus. The layout is $(cat /var/lib/dbus/machine-id)-$DISPLAY. You could try all displays in the case of GConf.