bug#48974: A possible shepherd bug (it's very minor)

[Joshua Branson via Bug reports for GNU Guix <bug-guix@gnu.org>]

Leo Prikler <leo.prikler@student.tugraz.at> writes:

> Hi,
>
> Am Freitag, den 02.07.2021, 18:57 -0400 schrieb Joshua Branson:
>> Leo Prikler <leo.prikler@student.tugraz.at> writes:
>> 
>> > Am Freitag, den 25.06.2021, 14:06 -0400 schrieb Joshua Branson:
>> > > Leo Prikler <leo.prikler@student.tugraz.at> writes:
>> > > 
>> > > > Hi,
>> > > > 
>> > > > Am Freitag, den 25.06.2021, 05:31 -0400 schrieb Joshua Branson:
>> > > > > Leo Prikler <leo.prikler@student.tugraz.at> writes:
>> > > 
>> > > Thanks again!  The current code doesn't quite work for me
>> > > yet.  I'll
>> > > try using match-lambda to define it.  I'll post again when I have
>> > > a
>> > > free moment.  When i get it working, I'll send a patch to the
>> > > manual
>> > > via guix-patches and CC you.  Is that ok?  Or would you rather
>> > > that
>> > > documentation be in the cookbook?
>> > Did I make a mistake or does it do the job only in a somewhat
>> > inelegant
>> > way?  I'm perfectly fine with the latter as I'm not the one using
>> > the
>> > code :P
>> 
>> I've got some code now that works!
>> 
>> #+BEGIN_SRC scheme
>> (define (auto-login-to-tty tty user config)
>>   (if (string=? tty (mingetty-configuration-tty config))
>>         (mingetty-configuration
>>          (inherit config)
>>          (auto-login user))
> Why do you need to inherit the config, when it doesn't change?  Seems
> like a pointless allocation to me.
>>         (mingetty-configuration
>>          (inherit config))))
>> 
>> ;; allegedly %desktop-services now contains network-manager-
>> applet...?  Can I remove that?
> Not with modify-services, but there's some filter example in the manual
> as well.
>> (define %my-desktop-services
>>   (modify-services %desktop-services ;;end of remove services
>>     (mingetty-service-type config =>
>>                            (auto-login-to-tty "3" "joshua" config))))
>> 
>> #+END_SRC
>> 
>> > I think the cookbook is a better destination for stuff like this.
>> 
>> I agree, but we should also probably fix the manual:
>> 
>> 10.1 Using the Configuration System
>> ===================================
>> 
>> System Services
>> 
>>    For example, suppose you want to modify ‘guix-daemon’ and Mingetty
>> (the console log-in) in the ‘%base-services’ list (*note
>> ‘%base-services’: Base Services.).  To do that, you can write the
>> following in your operating system declaration:
>> 
>> 
>>      (define %my-services
>>        ;; My very own list of services.
>>        (modify-services %base-services
>>          (guix-service-type config =>
>>                             (guix-configuration
>>                              (inherit config)
>>                              ;; Fetch substitutes from example.org.
>>                              (substitute-urls
>>                                (list "https://example.org/guix"
>>                                      "https://ci.guix.gnu.org"))))
>>             ;; it looks like the manual is telling you to set up
>>             ;; auto login on ALL ttys.
>>          (mingetty-service-type config =>
>>                                 (mingetty-configuration
>>                                  (inherit config)
>>                                  ;; Automatially log in as "guest".
>>                                  (auto-login "guest")))))
>> 
>>      (operating-system
>>        ;; ...
>>        (services %my-services))
>> 
>> How about I delete that section in the manual about automatic login
>> and
>> instead add this to the cookbook?
> No.  Read on, the manual clearly states that this affects *all* TTYs. 
> Presumably the guest user only has access to su and logout, maybe guix,
> but in any case they ought not to have access to anyone's $HOME, not
> even their own.
>
> The thing we've coded up here is a more involved process to solve a
> particular problem rather than a general demo of what services can do
> and thus belongs to the cookbook.
>
> Regards,
> Leo
>

-- 
Joshua Branson (joshuaBPMan in #guix)
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