need to restart cups to reach network printers

Question

Every once in a while (not necessarily after resuming from suspend or booting) I have to sudo /etc/init.d/cups restart to see again the network printers. Is there a way to bypass this process, or what is the best way to automate it under Lubuntu 16.04?

Printing has always been fiddly in my experience. Perhaps use a nightly crontab job to bounce the service? — thrig, Feb 01 '17 at 16:09
@thrig I thought of that, launching when it needs restart; but how to detect this situation? I had ubuntu installed in this machine before and this was not necessary, but yes, printing means trouble. — nightcod3r, Feb 01 '17 at 16:27
In the configuration of CUPS (/etc/cups/printers.conf) for each printer there is an entry `ErrorPolicy`. If this is set to `stop-printer`, the printer que will be stopped when the printer (temporarily) is not reachable, what could happen with network printers. Set this to `retry-job`, so CUPS won't stop the queue and retry the print job later. See e.g. http://superuser.com/questions/280396/how-to-resume-cups-printer-from-command-line — ridgy, Feb 01 '17 at 16:38
Is Ubuntu the exact same version as before? For detection, the various `lp*` commands may indicate what CUPS can see. — thrig, Feb 01 '17 at 16:41
@thrig right, `lpq -l` might do it. I was using Ubuntu 14.04. — nightcod3r, Feb 01 '17 at 17:48
@ridgy, not sure if I explained myself correctly. I meant that suddenly the printers are not there, when I try to print, they don't show, and only a `restart` brings them back to the list, and only now I can send a job. I.e., it is not a queuing problem. — nightcod3r, Feb 01 '17 at 17:51
@ridgy Have checked, and the `printers.conf` file contains exactly the same information in both cases (when printers show up, and when they're hidden). So, the problem is that after some time, I try to print from, say, Chrome, and the network printers don't show up. After restarting CUPS they're back again in the list, and can send them jobs. — nightcod3r, Feb 01 '17 at 20:26

score 2 · Answer 1 · edited Jul 13 '19 at 11:30

For Linux based shell script you can try to schedule script as below:

Crontab entry:

*/5 * * * * sh /scripts/cups_recursive_checking.sh

#/bin/sh
HOST='server-name'

/etc/init.d/cups status>/scripts/cups.txt

if grep "cupsd (pid " /scripts/cups.txt
then
    echo "cups is already running"
    exit
else
    /etc/init.d/cups restart
    echo "cups just now started in server-name"

    ############# For mail Notification whenever cups gets restart follow below line according to your email ##########

    mutt -e "my_hdr Content-Type: text/html" -e 'set realname=Notification' \
                    -e 'set [email protected]' [email protected] \
                    -s "CUPS Notification" < /scripts/cups.txt
fi
###END OF THE SCRIPT###

Example : To check the printers after the cups restart in Linux

lpstat -a

clientPrinter accepting requests since Sat 13 Jul 2019 10:07:01 AM IST

dmx accepting requests since Sat 13 Jul 2019 03:55:05 PM IST

HP_LaserJet_400_M401dw accepting requests since Sat 13 Jul 2019 03:05:06 PM IST

need to restart cups to reach network printers

1 Answers1