Re: Deleting services from %desktop-services in operating system declaration

[swedebugia@riseup.net]

On 2016-01-23 17:43, Alex Kost wrote:
> swedebugia@riseup.net (2016-01-23 16:09 +0300) wrote:
> 
>> On 2016-01-21 00:24, ludo@gnu.org wrote:
>>> swedebugia@riseup.net skribis:
>>> 
>>>> I have trouble getting the syntax right to delete avahi and wicd 
>>>> from
>>>> my config.scm.
>>> 
>>> The correct syntax would be:
>>> 
>>>   (operating-system
>>>     ;; …
>>>     (services (remove (lambda (service)
>>>                         (or (eq? (service-kind service)
>>>                                  wicd-service-type)
>>>                             (eq? (service-kind service)
>>>                                  avahi-service-type)))
>>>                       %desktop-services)))
>> 
>> I tried this and got this error:
>> # guix system reconfigure /etc/config/config.scm
>> guix system: error: failed to load '/etc/config/config.scm':
>> /etc/config/config.scm:48:12: In procedure #<procedure a7c3530 ()>:
>> /etc/config/config.scm:48:12: In procedure module-lookup: Unbound
>> variable: remove
> 
> 'remove' procedure is from (srfi srfi-1) module, so you need to use it
> in your config (see below).
> 
> Note that after fixing it, you'll get complaints about other unbound
> variables:
> 
> - 'avahi-service-type': it is from (gnu services avahi);
> 
> - 'tor-service': it is from (gnu services networking);
> 
> - 'wicd-service-type': it is also from (gnu services networking), but 
> it
>   is not exported (I think we should fix it), so now you have to use it
>   like this:
> 
>   (@@ (gnu services networking) wicd-service-type)
> 
>   which means: "give me 'wicd-service-type' from (gnu services
>   networking) module, and I don't care if it's not exported".
> 
>> Config here: https://paste.debian.net/367385/
> 
> I paste your config here for convenience:
> 
>> (use-modules (gnu) (gnu system nss))
> 
> (use-modules
>  (gnu)
>  (gnu system nss)
>  (srfi srfi-1))
> 
>> (use-service-modules desktop)
>> (use-package-modules xfce ratpoison certs)
> 
>> (operating-system
>>   (host-name "unknown")
>>   (timezone "Europe/Stockholm")
>>   (locale "en_US.UTF-8")
> 
>>   ;; Assuming /dev/sdX is the target hard disk, and "root" is
>>   ;; the label of the target root file system.
>>   (bootloader (grub-configuration (device "/dev/sda")))
>>   (file-systems (cons* (file-system
>>                         (device "guix")
>>                         (title 'label)
>>                         (mount-point "/")
>>                         (type "ext4"))
> 
>>   		      (file-system
>>                         (device "home")
>>                         (title 'label)
>>                         (mount-point "/home")
>>                         (type "ext4"))
>>                       %base-file-systems))
> 
>>   (swap-devices '("/dev/sdb3"))
> 
>>   (users (cons (user-account
>>                 (name "sdb")
>>                 (comment "swedebugia")
>>                 (group "users")
>>                 (supplementary-groups '("wheel" "netdev"
>>                                         "audio" "video"))
>>                 (home-directory "/home/sdb"))
>>                %base-user-accounts))
> 
>>   ;; Add Xfce and Ratpoison; that allows us to choose
>>   ;; sessions using either of these at the log-in screen.
>>   (packages (cons* xfce ratpoison    ;desktop environments
>>                    nss-certs         ;for HTTPS access
>>                    %base-packages))
> 
>>   ;; Use the "desktop" services, which include the X11
>>   ;; log-in service, networking with Wicd, and more.
>>   (services (remove (lambda (service)
>>                         (or (eq? (service-kind service)
>>                                  wicd-service-type)
>>                             (eq? (service-kind service)
>>                                  avahi-service-type)))
>>                       %desktop-services))
>>   (services (cons* (tor-service) %desktop-services))
> 
> You shouldn't (!) use 'services' (or any other operating-system field
> more than *ONCE*).  You can combine 'cons*' and 'remove' like this:
> 
>   (services
>    (cons* (tor-service)
>           (remove (lambda (service)
>                     (or (eq? (service-kind service)
>                              avahi-service-type)
>                         (eq? (service-kind service)
>                              (@@ (gnu services networking) 
> wicd-service-type))
>                         (eq? (service-kind service)
>                              (@@ (gnu services networking) 
> ntp-service-type))))
>                   %desktop-services)))

Thanks for the tip on how to combine them!

> 
> Note: if you want to remove wicd service, you also need to remove ntp
> service, otherwise you'll get:
> 
>   guix system: error: service 'ntpd' requires 'networking', which is 
> undefined

I got this error a couple of times. Thanks for the explanation - this 
was really helpful in getting my config to work properly.

I decided to keep wicd after all and just removed avahi. It seems that 
avahi is also not exported.

The full config with my comments is found here: 
https://paste.debian.net/368031/

I'm effectively learning Scheme/Guile while trying to hack GuixSD and I 
like it :D

cheers
sdb