CUPS sucks!

[ncoesel]

> On Aug 21, 2009, at 12:23 AM, ncoesel wrote:
> > I've spend the last two days trying to get cups to work on an
> > embedded platform.
>
> Um, CUPS is currently not supported on any embedded platforms,
> although I do know of several people playing with it there.

Huh??? Linux is linux. No matter what the platform is! You're probably referring to Linux distributions. The difference between distributions (paths & users) is usually covered by the automake/autoconf settings.

> > The major problem I'm experiencing is that Cups provides no
> > diagnostic information at all so I don't know what I must fix.
>
> You mean cupsd was not generating an error_log file listing the errors
> it found?

I've set the level to debug2. But it is not generating meaningfull errors. I'd expect if it finds a USB device port but can't access it, it reports an error in the log. The software I write does stuff like that and also provides hints to fix problems.

> > It appeared my lp0 device had insufficient rights. Doesn't say in
> > the documentation, I had to visit the links in 3 pages of Google
> > results before I found an obscure forum that gave a hint towards the
> > rights.
>
> The required permissions vary based on the Linux distribution you run;
> we don't document distribution-specific stuff...
>
> > Now I still need to solve an 'Unsupported format' problem.
>
> Sounds like you may want to enable raw printing - look at the
> mime.types and mime.convs files included with CUPS.

Sorry to be rude but 'Sounds like' isn't good enough for me. I want to know exactly why CUPS is giving me 'unsupported format'. Which programs it is trying to run (including paths and arguments), where parsing of a config file goes wrong, etc. According to internet forums there are several possible causes for the 'Unsupport format' error. The logfile should contain crystal clear information on what is causing the problem.

Some software actually provides the source file and line number of a problem when the log level is set to debug. The C/C++ macros __FILE__ (string) and __LINE__ (integer) can be used to generate this information so there is at least a possibility to trace the error by looking at the source (this is not an ideal solution ofcourse).

> > Guys (and girls), this really needs fixing!
>
> *What* needs fixing? Supporting embedded platforms? Documenting every
> platform's idiosyncrasies? Making the existing documentation more
> visible?

Cups should provide meaningfull errors and warnings to start with. For example the usb program. When I run it, it detects the printer just fine. When I run Cups, Cups can't detect te printer and doesn't generate any error or warning. This could be fixed by having Cups or the usb program report 'usb printer device found with insufficient rights' (or something like that).

> > The commands like lpstat, cupsd have no help to show the options (--
> > help) or to show the version (--version).
>
> There is a pending feature request for this; in short, we never
> implemented these options because they are not standard for those
> commands  and we have extensive help (http://localhost:631/help) and
> man page coverage.

--version is pretty standard. Perhaps on Windows you'd like something like /?. Anyway, it is a good custom to have some option that prints at least the version. What if you have two versions of Cups installed? How do you know which one is running? Which one is started when cupsd is started from the command line? We have quite a lot of systems in the field and there is no way to keep them at the same version. So being able to obtain version information is a first priority. Don't assume the man or the manual is installed on the system.