Error silently displayed on stdout only : Start/Stop printer operation failed

[Olivier Berger]

For some reason, a user on our system cannot resume a paused printer queue, which may be caused by another problem or misconfiguration, but that may happen.

However, HP-toolbox doesn't seem to do anything when that user clicks the "Start printer" button in "Printer Control", which is confusing.

Actually, it does print a message on stderr :
error: Start/Stop printer operation failed

But how would a GUI user know ?

It would be great to have such messages displayed in a GUI dialog of some kind instead of silently on the stderr.

Thanks in advance.

[Olivier Berger (olivierberger)]

FYI, the fact that a user isn't member of the lpadmin group explained the error on the Debian system where it happened. But this is just the cause of the error message and not a solution to this lack of graphical feedback to GUI users.

[Naga Samrat Chowdary, Narla (samrat-hplip)]

please run "hp-check -t" and post the output.

Thank you for supporting HPLIP,
Naga Samrat Chowdary, Narla

[Olivier Berger (olivierberger)]

Are you sure hp-check -t will actually be useful ? ... It's the code of hp-toolbox that's in cause here : the errors are displayed on stdout, period ;-)

Anyway, will try and provide what you ask, as I think it's probably mandatory requirements of your support procedures...

[Olivier Berger (olivierberger)]

Here's the output of hp-check -t

[Mark Purcell (msp)]

It should be trivial to have hp-check print an error message if the user isn't a member of the "lp" and "lpadmin" group.

[Mark Purcell (msp)]

--- /usr/bin/hp-check.orig 2010-04-08 11:10:50.000000000 +1000
+++ /usr/bin/hp-check 2010-04-09 07:55:25.000000000 +1000
@@ -873,6 +873,16 @@

         if status == 0:
             log.info(output)
+
+ if "lp " in output:
+ log.info(log.green("User member of group 'lp'. Enables print/ scan/ fax."))
+ else:
+ log.error("User needs to be member of group 'lp' to enable print, scan & fax.")
+
+ if "lpadmin" in output:
+ log.info(log.green("User member of group 'lpadmin'."))
+ else:
+ log.error("User needs to be member of group 'lpadmin' to manage printers.")

     tui.header("SUMMARY")

[Naga Samrat Chowdary, Narla (samrat-hplip)]

Some distributions has both lpadmin and lp group Ex. Debian and ubuntu
Some distributions has only lp group Ex. Fedora, RHEL and Suse.

if distribution supports lpadmin then user should be part of lpadmin, otherwise user should be part of "lp" group.
script may read /etc/group file to check for lpadmin and lp group availability.
then check weather is part of required group.

this bug should reflect both in prnt/cups.py (for device manager) and check.py (hp-check) files.

Please let me know if any thing wrong in my understanding.

Thanks!
Naga Samrat Chowdary, Narla

[Naga Samrat Chowdary, Narla (samrat-hplip)]

Some more updates!

on Fedora, user need be part of "sys" group to do operations, but not as part of "lpadmin" group.
but in "Ubuntu" user need to be part of lpadmin to do these operations.

It looks different from one distro to another distro.
I am working on it!!!

Thanks!
Naga Samrat Chowdary, Narla

[Naga Samrat Chowdary, Narla (samrat-hplip)]

Same thing is happening from cups web interface, if user is not part of "lpadmin" or "sys" or "lp" group.
CUPS is not giving or displaying any warning/error messages in this case.
Simply asking for Authentication for infinite number of times.

Ubuntu and debian required user to be part of "lpadmin" .
Fedora requires user to be part of "sys"
opensuse don't required user to be part of "lpadmin" and "sys"

But, as per CUPS documentation user should be part of "lpadmin" group.

HPLIP uses CUPS API calls for Pause/Resume/Start/Stop Printer queue operations.

This is logged at CUPS site at http://www.cups.org/str.php?L3555+P0+S-2+C0+I0+E0+M20+Q

Thanks!
Naga Samrat Chowdary, Narla

[Naga Samrat Chowdary, Narla (samrat-hplip)]

Patch for Qt4 platforms for Start/Stop/Accept/Reject/Set default Pritner queue operations.

Thanks!
Naga Samrat Chowdary, Narla

[Naga Samrat Chowdary, Narla (samrat-hplip)]

Patch for qt3 platforms

Thanks!
Naga Samrat Chowdary, Narla

[Naga Samrat Chowdary, Narla (samrat-hplip)]

Scenario when delete printer queue on Qt4.

[Naga Samrat Chowdary, Narla (samrat-hplip)]

Scenario when delete printer queue on Qt4.

Thanks!
Naga Samrat Chowdary, Narla

[Naga Samrat Chowdary, Narla (samrat-hplip)]

Delete printer queue on Qt3.

Thanks!
Naga Samrat Chowdary, Narla