Re: guix system: error: service 'ssh-daemon' requires 'networking', which is undefined

[ludo@gnu.org (Ludovic Courtès)]

Jan Synáček <jan.synacek@gmail.com> skribis:

> On Tue, Jul 19, 2016 at 2:43 PM, Ludovic Courtès <ludo@gnu.org> wrote:
>> I improved the message along these lines in commit
>> 2c2ec261a8d3c37e5147038f47ad24c57cde4134, let me know what you think.
>>
>> To be more concrete about other improvements, here’s what should be
>> feasible (but needs to be discussed to see whether it’s actually
>> helpful):
>>
>>   1. Display the location of the Shepherd service definition:
>>
>>        gnu/services/ssh.scm:160:4: 'ssh-daemon' requires 'networking'…
>>
>>      Trivial to implement, but the downside is that the user doesn’t
>>      really care about this file.
>>
>>   2. Same, but also show some sort of a stack trace (but not an actual
>>      Scheme stack trace) showing where this Shepherd service comes from:
>>
>>        gnu/services/ssh.scm:160:4: 'ssh-daemon' requires 'networking'…
>>        gnu/services/ssh.scm:117:30: … in extension of service 'shepherd'
>>        gnu/services/ssh.scm:228:2: … while folding service 'lsh’ instantiated here
>>
>>      The problem is that, currently, we’d get the location of the
>>      (service …) form, which is in the ‘lsh-service’ procedure, in
>>      gnu/services/ssh.scm.
>>
>>      It may be hard to come up with intelligible messages, and there’s a
>>      risk that showing too many lines of messages would be
>>      counterproductive.
>>
>> Thoughts?

Just to be clear, the message we now have is:

  service 'ssh-daemon' requires 'networking', which is not provided by any service

> From a regular user's point of view, this still misses the point,
> which I originally attempted to make. I suggest an error message like
> this:
>
> 'ssh-daemon' requires 'networking', try adding
> 'static-networking-service' or 'dhcp-client-service' to system
> services
>
> Or something like that. The point is, make it clear that "requires
> networking" means adding at least one service to the operating
> system's services and make at least one suggestion. Definitely a step
> forward to user friendliness.

So I think you’re saying that, in addition to the error message, you’d
like suggestions.

I like the idea.  However, in this specific case, I’m not sure how to
achieve it: ‘guix system’ doesn’t know about all the Shepherd services
that can possibly exist, so it cannot tell you that the ‘networking’ is
provided if you add ‘dhcp-client-service’ or whatnot to your config
file.

I understand these are not details one cares about as a user, at least
at first glance.  But this limits what we can do.

Thanks,
Ludo’.