Ok. This is fairly trivial stuff for many of you, but what I found interesting is that the SystemBus lets you shutdown/restart/suspend/hibernate as an ordinary user. Of course, if you think of a desktop, that is a pretty basic expectation of what an ordinary end-user should be able to do.
But when I think about a server, the thought that people can bypass a
while doing a
shutdown makes me uneasy. Of course then, dbus shouldn’t be
running on a server. Or anything which needs dbus. That means NetworkManager,
for one. Of course, servers don’t run NetworkManager. Silly me.
Of course, I didn’t want to shutdown my netbook while trying out the code. So I
Suspend. That gave me some fairly confusing
error message about some parameters being incorrect. Enough guessing. I decided
to RTFM. So I found this ubuntu wiki
So I corrected the code above to be instead: bus_object.Suspend(0, dbus_interface="org.freedesktop.Hal.Device.SystemPowerManagement")
And it indeed put my netbook to sleep.
You don’t need to code in Python to do this. The wiki above gives you the one line command to do this from the console.$ dbus-send --system --print-reply --dest="org.freedesktop.Hal" /org/freedesktop/Hal/devices/computer org.freedesktop.Hal.Device.SystemPowerManagement.Suspend int32:0