On-demand starting/stopping of cups [was: [Blueprint client-1305-printing-stack-with-mobile-in-mind] Printing Stack with Mobile in Mind]

[Till Kamppeter]

On 05.02.2014 06:40, Martin Pitt wrote:
> Yes, agreed. I'm not concerned about cups' start up time, that's
> negligible. I'm primarily concerned about the time that it takes to
> detect remote printers, as they are only advertised/broadcast every so
> often (30s?). For that I think we ought to have at least avahi running
> permanently, so that it can pick up remote services and then when
> cups/cups-browsed get activated they can immediately use remote
> printers. That assumes that it's actually avahi-daemon which
> stores/caches those; if that's not the case, then cups-browsed needs
> to run all the time instead.

pitti, I remember that the old CUPS broadcasting (by CUPS itself, 
without Avahi/Bonjour) was happening only every 30 sec. The new 
Avahi/Bonjour method seems to be faster. But note that for testing I 
have run the following script

----------
sudo stop cups-browsed
sudo stop cups
sudo stop avahi-daemon
sleep 10
sudo start avahi-daemon
sudo start cups
sudo start cups-browsed
watch lpstat -v
----------

Now I do not know whether avahi-daemon is creating a cache file to 
conserve the cached items while being shut down and restarted later. 
With this script the queues appear in ~4 sec.

    Till