Re: Multiple sessions for the same user?

[Shaun McCance <shaunm gnome org>]

On Mon, 2007-12-17 at 10:42 -0500, Havoc Pennington wrote:
> Hi,
> 
> Stef Walter wrote:
> > This may be a dumb question, but I'm wondering if we support (or it is a
> > goal to support) multiple sessions for the same user in GNOME.
> > 
> > As far as I can tell a lot of GNOME software doesn't currently take that
> > into account. I'm working on gnome-keyring-daemon, and I'm wondering if
> > I need to keep multiple sessions in mind or just take the much simpler
> > approach of one session per user.
> > 
> 
> Everything needs to hang off either the session dbus daemon or the X 
> server, then it should Just Work for multiple sessions. By "hang off" I 
> mean some arrangement such that the user gets 1 daemon for each X server 
> or dbus bus, and such that the 1 daemon exits when either the X server 
> or the dbus bus exits. The lifetime of the  X server and the dbus bus 
> should be the same (they should exit together) in a properly-configured 
> GNOME setup, so it does not matter which one you use.
> 
> The only other, possibly-sane alternative is per-machine or 
> per-(user,machine) or per-(session,machine) scoping (i.e. have a socket 
> in /tmp, or hang off the system dbus daemon, possibly including username 
> or dbus session uuid in the socket or bus name). However, this is wrong 
> for most purposes, so be careful. And you have to be sure there's some 
> way to exit the daemon when there are no active sessions.
> 
> Historical GNOME problems in this area have come from gconfd and Bonobo 
> components getting the scoping wrong; they should have been per-session, 
> but were not.

I frequently use XNest at work when I do builds that open
and close thousands and thousands of windows automatically.
Running the builds in an XNest window ensures these windows
never pop up in front of me and never steal focus.

The single most common problem I have is with applications
that use bonobo for single-instance activation.  If I have
FooApp open in my main session, then launch FooApp in XNest,
I just get another FooApp window in my main session, rather
than a new instance of it inside XNest.  Very annoying.

--
Shaun