Re: Hooking up gnome-session with dbus/kdbus/systemd

[Martyn Russell <martyn lanedo com>]

Hello Lennart, all,

Love the initiative here.

> On 21/01/14 18:08, Lennart Poettering wrote:
> So, the way I'd like this all to work is by simply emphasizing .desktop
> files and bus activation a lot more, without actually emphasizing
> systemd as backend implementation of anything. As both technologies
> (.desktop files and dbus) are universially supported wherever GNOME is
> supported this should be a good approach:

I am keen to see how this would play out with Tracker as we have a bunch 
of .desktop and .service files.

> a) I'd like to see native D-Bus ".service" activation files deprecated
>     in dbus. Instead, for the user/session bus, I'd like to see
>     everything moved to .desktop files. Ryan recently extended the
>     .desktop spec for declaring bus names in .desktop files so that
>     applications no longer need to be forked off directly, but can simply
>     be bus activated. I'd like to take this one step further:

That's pretty cool, didn't know about this.

You suggest moving everything to .desktop files (presumably .service 
file information too), but later say you're not keen on Simon's idea to 
merge the two. Can't we have that as an alternative to native service 
definition files? What are your concerns here?

On 21/01/14 18:49, Giovanni Campagna wrote:
> This won't work, because the Exec line from .service has a different
> purpose than the Exec line from .desktop: the first runs the service,
> the second activates the application provided by the service (ie, it
> opens a window)

We don't have different Exec purposes but we do abuse the service files 
currently.

$ git ls-files|grep -i -E '(service|desktop).in'
dbus/org.freedesktop.Tracker1.Miner.Applications.service.in
dbus/org.freedesktop.Tracker1.Miner.EMails.service.in
dbus/org.freedesktop.Tracker1.Miner.Extract.service.in
dbus/org.freedesktop.Tracker1.Miner.Files.service.in
dbus/org.freedesktop.Tracker1.Miner.RSS.service.in
dbus/org.freedesktop.Tracker1.Miner.Userguides.service.in
dbus/org.freedesktop.Tracker1.Writeback.service.in
dbus/org.freedesktop.Tracker1.service.in
miners/tracker-miner-applications.desktop.in.in
miners/tracker-miner-evolution.desktop.in.in
miners/tracker-miner-extract.desktop.in.in
miners/tracker-miner-files.desktop.in.in
miners/tracker-miner-rss.desktop.in.in
miners/tracker-miner-userguides.desktop.in.in
tracker-miner-fs.desktop.in.in
tracker-miner-rss.desktop.in.in
tracker-store.desktop.in.in

Some of the above service files use the same binary, for example the 
applications and files. We use the service files to know about data 
"miners" so we can list them with processes like tracker-control -F 
which polls the status of each miner. We also use these service files to 
be able to start or stop those miners. Perhaps abusing the freedesktop 
specs a bit here, but it was an easy way to do it at the time.

Migration won't be an issue, i'm sure and we should probably fix this.

> On 21/01/14 20:21, Simon McVittie wrote:
> Possibly slightly silly idea: desktop files are .ini-style, D-Bus
> services are .ini-style, so a file containing both would not be
> unreasonable...

I actually really like this idea, the .service files are just Name + 
Exec for us and it would simplify the files we have to maintain here.

Thanks,

--
Regards,
Martyn

Founder & Director @ Lanedo GmbH.
http://www.linkedin.com/in/martynrussell