Launch e.g. notification-daemon as needed?

[Simon McVittie]

On Thu, 17 Aug 2017 at 11:34:02 -0700, Jack Bates wrote:
> I'm not super familiar with the D-Bus architecture -- if someone calls an
> interface that requires a daemon, should that daemon get launched as needed?

In general it will be, because the daemon installs a D-Bus .service
file to make itself an *activatable service* (jargon term).

However...

> Currently if I send a desktop notification and notification-daemon isn't
> running, nothing happens

The org.freedesktop.Notifications interface is a special case. You
can't necessarily rely on implementations of it being activatable,
because it's very desktop-specific, with each desktop wanting to
provide its own UX - GNOME 3, Cinnamon and KDE Plasma Desktop have an
implementation of Notifications built into the GUI shell alongside the
window manager etc., while MATE, LXQT and XFCE have their own preferred
daemons as separate packages. The desktops like LXDE that (prefer to)
use a generic implementation are now relatively rare.

    S