Only one instance of the daemon and datahub should be allowed to run at once

[Natan Yellin]

It's currently possible to run multiple instances of zeitgeist-daemon and zeitgeist-datahub at once. This shouldn't be allowed- both the daemon and the datahub should check on startup that they're not already running in a different process.

[Natan Yellin (aantny)]

I'm assigning this to myself- I'll commit a fix by tomorrow afternoon.

[Siegfried Gevatter (rainct)]

Hehe, just a while ago we discussed in #zeitgeist that this is
something we should do :).

Just to be sure, you're going to check if it's already running looking
if it's using the D-Bus, right?

--
Siegfried-Angel Gevatter Pujals (RainCT)
Ubuntu Developer. Debian Contributor.

[Natan Yellin (aantny)]

Right now I'm planning on just using D-Bus directly, but eventually I'd like to switch to GtkUnique.

By default, GtkUnique uses to D-Bus to ensure that your app only has one running instance. (Just like we would.) However, it also can do so without D-Bus (using xlib or sockets), which may prove to be useful in the future.

(I'm not using GtkUnique right now because as far as I know there aren't any Python bindings.)

[Natan Yellin (aantny)]

I committed a fix for the daemon in rev. 939. I'll probably finish the Datahub tomorrow.

[Sense Egbert Hofstede (sense)]

Wouldn't using GtkUnique make the daemon depend on GTK+, something that was to be prevented iirc?
LibUnique depens on LibGTK2.0, and I suspect that any Python implementation would do the same. Maybe something not depending on GTK should be created by Zeitgeist.

[Natan Yellin (aantny)]

Yes, you're correct. (At the time I wrote about GtkUnique we hadn't yet decided to make the daemon Gtk-free.)

If we want the daemon's DBUS requirement to be optional, then I think we'll just have to reimplement something like GtkUnique. (Or it might be possible to remove the Gtk dependency from GtkUnique.)

[Seif Lotfy (seif)]

I think this issue has been tackled right? If yes then please close it! Else target it!

[Natan Yellin (aantny)]

Sorry, it hasn't been fixed in the datahub yet. I'll fix it soon.

[Sense Egbert Hofstede (sense)]

There is a good example here: http://www.le-web.org/2008/10/30/python-allow-only-one-instance-of-your-application/

Maybe useful?

[Natan Yellin (aantny)]

Thanks Sense. That looks quite useful for implementing a backend that doesn't use D-BUS.