Run a system command in home configuration file

Run a system command in home configuration file

[Reza Housseini]

Hello guix

I want to run a system command and use the output inside my ssh config
file. Below is the service configuration I'm talking about and my current
implementation which does not work, probably because the command is run
from the daemon, but I need it to run from the current user. Has anyone an
idea how to achieve this?

(simple-service 'ssh-config
 home-files-service-type
 (list `("ssh/config"
 ,(mixed-text-file "config" "
Host *
  IdentityAgent " #~(system* #$(file-append gnupg "/bin/gpgconf")
"--list-dirs" "agent-ssh-socket") "
"))))

Thanks and cheers,
Reza

Re: Run a system command in home configuration file

[Ludovic Courtès]

Hi,

Reza Housseini <reza.housseini@gmail.com> skribis:

> I want to run a system command and use the output inside my ssh config
> file. Below is the service configuration I'm talking about and my current
> implementation which does not work, probably because the command is run
> from the daemon, but I need it to run from the current user. Has anyone an
> idea how to achieve this?
>
> (simple-service 'ssh-config
>  home-files-service-type
>  (list `("ssh/config"
>  ,(mixed-text-file "config" "
> Host *
>   IdentityAgent " #~(system* #$(file-append gnupg "/bin/gpgconf")
> "--list-dirs" "agent-ssh-socket") "
> "))))

Instead of #~(system* …) above, you could do something like:

  (let* ((pipe (open-input-pipe "gpgconf" …))
         (data (get-string-all pipe)))
    (close-pipe pipe)
    data)

The effect will be that ‘gpgconf’ will run when you invoke ‘guix system
reconfigure’, as the user who invokes it.  (You need the (ice-9 popen)
and (rnrs io bytevectors) modules.)

I can’t necessarily recommend it because it’s kinda wild, but it should
do the trick.

HTH,
Ludo’.

Re: Run a system command in home configuration file

[Reza Housseini]

On 3/8/22 11:33, Ludovic Courtès wrote:
> Hi,
>
> Reza Housseini <reza.housseini@gmail.com> skribis:
>
>> I want to run a system command and use the output inside my ssh config
>> file. Below is the service configuration I'm talking about and my current
>> implementation which does not work, probably because the command is run
>> from the daemon, but I need it to run from the current user. Has anyone an
>> idea how to achieve this?
>>
>> (simple-service 'ssh-config
>>   home-files-service-type
>>   (list `("ssh/config"
>>   ,(mixed-text-file "config" "
>> Host *
>>    IdentityAgent " #~(system* #$(file-append gnupg "/bin/gpgconf")
>> "--list-dirs" "agent-ssh-socket")"
>> "))))
> Instead of #~(system* …) above, you could do something like:
>
>    (let* ((pipe (open-input-pipe "gpgconf" …))
>           (data (get-string-all pipe)))
>      (close-pipe pipe)
>      data)
>
> The effect will be that ‘gpgconf’ will run when you invoke ‘guix system
> reconfigure’, as the user who invokes it.  (You need the (ice-9 popen)
> and (rnrs io bytevectors) modules.)
>
> I can’t necessarily recommend it because it’s kinda wild, but it should
> do the trick.
>
> HTH,
> Ludo’.


Hi Ludo

Thanks for the reply, it really looks kinda wild :)

Isn't there a general need to run certain commands for  specific user 
especially in the context of guix home?

Cheers,

Reza

Re: Run a system command in home configuration file

[Efraim Flashner]

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On Tue, Mar 08, 2022 at 03:38:19PM +0100, Reza Housseini wrote:
> 
> On 3/8/22 11:33, Ludovic Courtès wrote:
> > Hi,
> > 
> > Reza Housseini <reza.housseini@gmail.com> skribis:
> > 
> > > I want to run a system command and use the output inside my ssh config
> > > file. Below is the service configuration I'm talking about and my current
> > > implementation which does not work, probably because the command is run
> > > from the daemon, but I need it to run from the current user. Has anyone an
> > > idea how to achieve this?
> > > 
> > > (simple-service 'ssh-config
> > >   home-files-service-type
> > >   (list `("ssh/config"
> > >   ,(mixed-text-file "config" "
> > > Host *
> > >    IdentityAgent " #~(system* #$(file-append gnupg "/bin/gpgconf")
> > > "--list-dirs" "agent-ssh-socket")"
> > > "))))
> > Instead of #~(system* …) above, you could do something like:
> > 
> >    (let* ((pipe (open-input-pipe "gpgconf" …))
> >           (data (get-string-all pipe)))
> >      (close-pipe pipe)
> >      data)
> > 
> > The effect will be that ‘gpgconf’ will run when you invoke ‘guix system
> > reconfigure’, as the user who invokes it.  (You need the (ice-9 popen)
> > and (rnrs io bytevectors) modules.)
> > 
> > I can’t necessarily recommend it because it’s kinda wild, but it should
> > do the trick.
> > 
> 
> Thanks for the reply, it really looks kinda wild :)
> 
> Isn't there a general need to run certain commands for  specific user
> especially in the context of guix home?
> 

One option is a one-off shepherd service. For finding the
SSH_AUTH_SOCKET using gpgconf I stuck with the tried and true method of
setting it in .bash_profile¹.

¹ https://git.sr.ht/~efraim/guix-config/tree/master/item/efraim-home.scm#L694

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