Printer configuration failed due to missing filters

Printer configuration failed due to missing filters

[Daniel Meißner]

Hi Guix!

I am currently trying to configure my Epson printer on Guix system using
system-config-printer.  The printer is connected via USB and is
automatically detected in the dialog window that opens if I click on
"Add". I select the printer from the list and click on "Forward", then I
enter the printer name, a description and a location in the section
"Describe Printer".  However, if I click on "Apply", the following error
message is printed:

> Printer 'EPSON-...' requires the
> '/gnu/store/...-cups-2.3.3/lib/cups/filter/epson-escpr-wrapper',
> program but it is not currently installed. Please install it before
> using this printer.

The printer is added but trying to print a test page yields: ‘CUPS
server error.  There was an error during the CUPS operation: ’No such
file or directory’.’ According to the Guix manual, the epson-escpr
filter should be installed by default when using the cups-service-type.
Nevertheless, I also made it explicit in my system configuration:

--8<---------------cut here---------------start------------->8---
(service cups-service-type
         (cups-configuration
          (extensions
           (list cups-filters
                 epson-inkjet-printer-escpr))))
--8<---------------cut here---------------end--------------->8---

Looking in the system profile I cannot find it: ‘find
/run/current-system/profile -name "epson-escpr-wrapper"’ shows no
results.  There is also no cups directory under
/run/current-system/profile/lib.  Am I missing something?

Since I am running Gnome, I also tried to configure the printer using
gnome-control-center.  However, here the error message is not so
detailed.  It just says: ‘Failed to add new printer’.

I think this is an issue specific to Guix because the printer works with
other Linux distros.

Best
Daniel

Re: Printer configuration failed due to missing filters

[Tobias Geerinckx-Rice]

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Daniel!

Daniel Meißner 写道：
>> Printer 'EPSON-...' requires the
>> '/gnu/store/...-cups-2.3.3/lib/cups/filter/epson-escpr-wrapper',
>> program but it is not currently installed. Please install it 
>> before
>> using this printer.

Interesting here is that it's looking in …-cups-2.3.3 where I 
believe it should look in …-cups-server-bin instead.  The former 
is merely the upstream CUPS package, whilst the latter is a union 
of CUPS with its extensions (drivers).

Can you confirm that the file printed by

  $ ps auxwww | grep -o '/gnu/store/[^ ]*cups-files.conf'

contains

  DataDir /gnu/store/…-cups-server-bin/share/cups
  ServerBin /gnu/store/…-cups-server-bin/lib/cups

?

You should find lib/cups/filter/epson-escpr-wrapper under this 
ServerBin.

> Looking in the system profile I cannot find it: ‘find
> /run/current-system/profile -name "epson-escpr-wrapper"’ shows 
> no
> results.  There is also no cups directory under
> /run/current-system/profile/lib.  Am I missing something?

Just that there's no reason for epson-escpr-wrapper to be anywhere 
in /run/current-system in the first place.  It should be in the 
union directory I mentioned above, and CUPS should find it there.

I don't currently have access to an Epson printer, but I'll try to 
add one anyway.

See if you can divine any useful chunks from the puddle of vomit 
that CUPS produces when configured with:

  (cups-configuration
    …
    (log-level 'debug2)
    …)

There's also (access-log-level 'all) but it's probably not 
relevant here.

Kind regards,

T G-R

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Re: Printer configuration failed due to missing filters

[Tobias Geerinckx-Rice]

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Tobias Geerinckx-Rice 写道：
> Interesting here is that it's looking in …-cups-2.3.3 where I 
> believe
> it should look in …-cups-server-bin instead.

Specifically through the standard $PATH mechanism:

  …
  envp[10]="PATH=/gnu/store/…-cups-server-bin/lib/cups/filter:…"
  …

(from /var/log/cups/error_log).

Kind regards,

T G-R

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Re: Printer configuration failed due to missing filters

[Daniel Meißner]

Hi Tobias!

Thank you for responding promptly.

> Can you confirm that the file printed by
>
>   $ ps auxwww | grep -o '/gnu/store/[^ ]*cups-files.conf'
>
> contains
>
>   DataDir /gnu/store/…-cups-server-bin/share/cups
>   ServerBin /gnu/store/…-cups-server-bin/lib/cups
>
> ?

Affirmative, this file contains those two lines.

> You should find lib/cups/filter/epson-escpr-wrapper under this 
> ServerBin.

Aha! Yes, it is there, indeed.

>> Looking in the system profile I cannot find it: ‘find
>> /run/current-system/profile -name "epson-escpr-wrapper"’ shows no
>> results.  There is also no cups directory under
>> /run/current-system/profile/lib.  Am I missing something?
>
> Just that there's no reason for epson-escpr-wrapper to be anywhere 
> in /run/current-system in the first place.  It should be in the 
> union directory I mentioned above, and CUPS should find it there.

I see, I am very new to Guix, so I don't know the internals of Guix
really.  I naively assumed that I should find it in the system profile.

> I don't currently have access to an Epson printer, but I'll try to 
> add one anyway.

That'd be awesome, thank you.

> See if you can divine any useful chunks from the puddle of vomit 
> that CUPS produces when configured with:
>
>   (cups-configuration
>     …
>     (log-level 'debug2)
>     …)
>
> There's also (access-log-level 'all) but it's probably not 
> relevant here.

Thanks for the hints, I will try to destill something from the logs.

Best
Daniel

Re: Printer configuration failed due to missing filters

[Tobias Geerinckx-Rice]

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Daniel,

Daniel Meißner 写道：
> I am currently trying to configure my Epson printer on Guix 
> system using
> system-config-printer.  The printer is connected via USB and is
> automatically detected in the dialog window that opens if I 
> click on
> "Add". I select the printer from the list and click on 
> "Forward", then I
> enter the printer name, a description and a location in the 
> section
> "Describe Printer".  However, if I click on "Apply", the 
> following error
> message is printed:

I was unable to reproduce this at all, albeit without an Epson USB 
printer connected, of course.

My steps through the CUPS Web interface:
- Administration
- Add Printer
- Internet Printing Protocol (ipp)
  Continue
- Connection: "ipp://fake.printer/print/Print"
  Continue
- Description, Location: "test"
  Share This Printer unticked
  Continue
- Make: Epson
  Continue
- Model: EPSON ET-2600 Series , Epson Inkjet Printer Driver
         (ESC/P-R) for Linux (…)
- Then accept all default options.

Result attached.  At no point do I get an error.

Interestingly, my CUPS only ever looks in the right location for 
epson-escpr-wrapper:

--8<---------------cut here---------------start------------->8---
λ grep escpr-wrapper -a /var/log/cups/error_log 
d [03/Dec/2021:00:17:28 +0100] 
add_printer_filter(p=0x64654c639bd0(test), 
filtertype=0x64654c5b7ca0(printer/test), 
filter="application/vnd.cups-raster 0 epson-escpr-wrapper")
d [03/Dec/2021:00:17:28 +0100] test: File 
\"/gnu/store/bmb3hz0a4k5a51bb5w7lxlc766d1hcv3-cups-server-bin/lib/cups/filter/epson-escpr-wrapper\" 
permissions OK (040555/uid=0/gid=0).
d [03/Dec/2021:00:17:28 +0100] add_printer_filter: test: adding 
filter application/vnd.cups-raster printer/test 0 
epson-escpr-wrapper
d [03/Dec/2021:00:17:33 +0100] 
add_printer_filter(p=0x64654c639bd0(test), 
filtertype=0x64654c5b7ca0(printer/test), 
filter="application/vnd.cups-raster 0 epson-escpr-wrapper")
d [03/Dec/2021:00:17:33 +0100] test: File 
\"/gnu/store/bmb3hz0a4k5a51bb5w7lxlc766d1hcv3-cups-server-bin/lib/cups/filter/epson-escpr-wrapper\" 
permissions OK (040555/uid=0/gid=0).
d [03/Dec/2021:00:17:33 +0100] add_printer_filter: test: adding 
filter application/vnd.cups-raster printer/test 0 
epson-escpr-wrapper
--8<---------------cut here---------------end--------------->8---

I can even print a test page (from the Maintenance drop-down).  Of 
course it fails to connect to the printer, but still the filter 
seems to run perfectly:

--8<---------------cut here---------------start------------->8---
λ grep escpr-wrapper -a /var/log/cups/error_log 
D [03/Dec/2021:00:28:45 +0100] [Job 46] epson-escpr-wrapper 
(application/vnd.cups-raster to printer/test, cost 0)
d [03/Dec/2021:00:28:45 +0100] test: File 
\"/gnu/store/bmb3hz0a4k5a51bb5w7lxlc766d1hcv3-cups-server-bin/lib/cups/filter/epson-escpr-wrapper\" 
permissions OK (040555/uid=0/gid=0).
d [03/Dec/2021:00:28:45 +0100] cupsdStartProcess: Preparing to 
start 
"/gnu/store/bmb3hz0a4k5a51bb5w7lxlc766d1hcv3-cups-server-bin/lib/cups/filter/epson-escpr-wrapper", 
arguments:
d [03/Dec/2021:00:28:45 +0100] cupsdStartProcess: argv[8] = 
"/gnu/store/bmb3hz0a4k5a51bb5w7lxlc766d1hcv3-cups-server-bin/lib/cups/filter/epson-escpr-wrapper"
d [03/Dec/2021:00:28:45 +0100] 
cupsdStartProcess(command="/gnu/store/bmb3hz0a4k5a51bb5w7lxlc766d1hcv3-cups-server-bin/lib/cups/filter/epson-escpr-wrapper", 
argv=0x7fffc0e0f148, envp=0x7fffc0e0fad8, infd=25, outfd=28, 
errfd=20, backfd=21, sidefd=23, root=0, profile=(nil), 
job=0x64654c5bf1b0(46), pid=0x64654c5bf2d0) = 32624
I [03/Dec/2021:00:28:45 +0100] [Job 46] Started filter 
/gnu/store/bmb3hz0a4k5a51bb5w7lxlc766d1hcv3-cups-server-bin/lib/cups/filter/epson-escpr-wrappe 
(PID 32624)
D [03/Dec/2021:00:28:45 +0100] [Job 46] pdftopdf: Last filter 
determined by the PPD: epson-escpr-wrapper; FINAL_CONTENT_TYPE: 
application/vnd.cups-raster => pdftopdf will not log pages in 
page_log.
--8<---------------cut here---------------end--------------->8---

So we'll need more info.  Especially your printer model (I chose 
one at random :-) and similar debug log.

Kind regards,

T G-R


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Re: Printer configuration failed due to missing filters

[Daniel Meißner]

Hi Tobias,

> Daniel Meißner 写道：
>> I am currently trying to configure my Epson printer on Guix system
>> using system-config-printer.  The printer is connected via USB and is
>> automatically detected in the dialog window that opens if I click on
>> "Add". I select the printer from the list and click on "Forward",
>> then I enter the printer name, a description and a location in the
>> section "Describe Printer".  However, if I click on "Apply", the
>> following error message is printed:
>
> I was unable to reproduce this at all, albeit without an Epson USB
> printer connected, of course.

Using the web-interface of CUPS I could add my printer seamlessly and
even print a test page.  So thanks!  However, as mentioned in [1], the
web interface responded super slowly which was the reason to use
system-config-printer and gnome-control-center in the first place.
After the fix the web-interface now runs smoothly.

However, gnome-control-center still `Failed to add new printer' and
system-config-printer still prints the error message I mentioned before.
As before it adds the printer but refuses to print a test page saying
‘There was an error during the CUPS operation: 'No such file or
directory'’.

Nevertheless, I found that it is possible to print a PDF document from
evince on the very same printer that I added using
system-config-printer.  So the problem seems to lie within
system-config-printer (and not CUPS) searching the right PATH for the
Epson filter.  Additionally, gnome-control-center does not seem to work
at all in that regard because I did not manage to add the printer with
it.

I am happy now since I am able to print but maybe it is worthwhile
investigating this issue with gnome-control-center within the
core-updates-frozen branch.  Because this would be the first place to
try to add printers for new Guix users that use Gnome.  I would be happy
to help although I can probably only try to reproduce this issue on
core-updates-frozen.

Best
Daniel


1: https://lists.gnu.org/archive/html/help-guix/2021-12/msg00010.html