How can I make a fake "active session” for
gconf?

I can reproduce this by installing
GConf 2.24 on my machine. GConf 2.22 works fine, but 2.24 breaks it.

GConf is failing to launch because D-Bus is not running. Manually
spawning D-Bus and the GConf daemon makes this work again.

I tried to spawn the D-Bus session bus by doing the following:

import dbus
dummy_bus = dbus.SessionBus()

...but got this:

dbus.exceptions.DBusException: org.freedesktop.DBus.Error.Spawn.ExecFailed: dbus-launch failed to autolaunch D-Bus session: Autolaunch error: X11 initialization failed.

Weird. Looks like it doesn't like to come up if X isn't running. To
work around that, start dbus-launch manually (IIRC use the os.system() call):

$ dbus-launch 
DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-eAmT3q94u0,guid=c250f62d3c4739dcc9a12d48490fc268
DBUS_SESSION_BUS_PID=15836

You'll need to parse the output somehow and inject them into
environment variables (you'll probably want to use os.putenv). For my testing, I just used the shell,
and set the environment vars manually with export
DBUS_SESSION_BUS_ADDRESS=blahblah..., etc.

Next, you need to launch gconftool-2 --spawn with those
environment variables you received from dbus-launch. This
will launch the GConf daemon. If the D-Bus environment vars are not set,
the daemon will not launch.

Then, run your GConf code. Provided you set the D-Bus session bus
environment variables for your own script, you will now be able to
communicate with the GConf daemon.

I know it's complicated.

gconftool-2 provides a --direct option that
enables you to set GConf variables without needing to communicate with
the server, but I haven't been able to find an equivalent option for the
Python bindings (short of outputting XML manually).

Edit: For future reference, if anybody wants to run dbus-launch
from within a normal bash script (as opposed to a Python
script, as this thread is discussing), it is quite easy to retrieve the
session bus address for use within the script:

#!/bin/bash

eval `dbus-launch --sh-syntax`

export DBUS_SESSION_BUS_ADDRESS
export DBUS_SESSION_BUS_PID

do_other_stuff_here

Well, I think I understand the
question. Looks like your script just needs to start the dbus daemon, or
make sure its started. I believe "session" here refers to a dbus
session. (here is some evidence), not a Gnome session. Dbus
and gconf both run fine without Gnome.

Either way, faking an "active session" sounds like a pretty bad idea.
It would only look for it if it needed it.

Perhaps we could see the script in a pastebin? I should have really
seen it before making any comment.