Re: [PATCH 3/3] gnu: Add CUPS service.

[Andy Wingo <wingo@igalia.com>]

On Fri 07 Oct 2016 22:24, Andy Wingo <wingo@igalia.com> writes:

> * gnu/services/cups.scm: New file.
> * gnu/local.mk (GNU_SYSTEM_MODULES): Add gnu/services/cups.scm.
> * doc/guix.texi (Printing Services): New section.

With this, I can print :)

Status:

 * There are no foomatic PPD's, as we have not packaged foomatic yet.
   Once that's packaged I think an easy way to add them would be to
   simply add that package to the default value of the
   cups-configuration "extensions" field.  Or, make a service and add it
   to your services:

     (define (make-cups-extension name package)
       (service
        (service-type
          (name name)
          (extensions
           (list (service-extension cups-service-type identity))))
        package))))))

     (operating-system
       ...
       (services (cons (make-cups-extension 'foomatic foomatic) ...)))

   For now, cups-filters is the only extension installed by default.

 * (cups-service) should probably be added to the desktop-services.

 * The web interface is off by default; to turn it on you have to

     (cups-service
       (cups-configuration (web-interface? #t)))

   Probably should default to on, methinks.

 * I have tested adding a network printer via the web interface
   (http://localhost:631, also over https://localhost:631 if you add the
   self-signed cert exception), and printing to that printer.  Works, it
   seems.

 * However printing test pages doesn't work!  The way this works is that
   CUPS constructs a filter chain bannertopdf -> pdftopdf -> pdftoraster
   -> ... or something, and these are processes that are run
   sequentially, transforming a file.  Well bannertopdf isn't finding
   the needed PDF.  A bug.

 * The cups-filters change ends up causing the GTK's to rebuild, and
   this the graphical world.  Bummer.

I'll commit in a couple days if no objections.

Andy