[systemd-devel] DBus signal on unit start/stop

Ragnar Thomsen rthomsen6 at gmail.com
Tue Dec 3 08:26:15 PST 2013

On Saturday 30 November 2013 19:30:12 you wrote:
> There are standard dbus PropertiesChanged signals sent out for ActiveState
> changes, which invalidate the properties when they change in released
> versions of systemd, and which carry the new values along in git.
> We probably should document which ones we generate this for in
> http://www.freedesktop.org/wiki/Software/systemd/dbus/
> Lennart

Thanks for your reply. I have now been playing around with the 
PropertiesChanged signal and found it quite useful for getting updates from 
systemd. By hooking it up with a Qt slot I can update the UI on any unit 
changes. The only drawback is that I am not able to get information about 
which unit had its properties changed from the signal, so I have to update the 
entire list of units. However, this is much better than querying for unit 
changes at certain time intervals.

Another issue I noticed is that enabling/disabling a unit's files through the 
dbus methods (EnableUnitFiles/DisableUnitFiles) does not update the 
UnitFileState property for the unit.
When enabling/disabling units using the systemctl tool, the systemd daemon 
gets reloaded so the property gets updated.
Is this the intended behavior?

Ragnar Thomsen

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