Re: Creating Docker containers in Scheme

[Ludovic Courtès]

Roel Janssen <address@hidden> skribis:

> Ludovic Courtès writes:

[...]

>> Move precisely:
>>
>>   (mlet %store-monad ((profile (profile-derivation …)))
>>     (docker-image "my-container" profile))
>>
>
> Oh, of course! :)
>
> Unfortunately, I cannot seem to get it to work.
> Here's what I do (mind the GWL process- stuff):
>
> (define* (process->docker-derivation proc #:key (guile (default-guile)))
>   "Return a Docker container that can run the PROCEDURE described in PROC, 
> with
> PROCEDURE's imported modules in its search path."
>   (let ((name (process-full-name proc))
>         (exp (process-procedure proc))
>         (out (process-output-path proc))
>         (packages (process-package-inputs proc)))
>     (let ((out-str (if out (format #f "(setenv \"out\" ~s)" out) "")))
>       (mlet %store-monad ((set-load-path
>                            (load-path-expression (gexp-modules exp)))
>                           (container (docker-image
>                                       (string-append (process-full-name proc)
>                                                       "-docker")
>                                       (profile-derivation
>                                        (packages->manifest packages)))))
                                        ^^
See above.  :-)

>         (gexp->derivation
>          name
>          (gexp
>           (call-with-output-file (ungexp output)
>             (lambda (port)
>               (format port "# Docker image: ~a~%" (ungexp container)))))
>          #:graft? #f)))))
>
> And the error I get is:
>   wrong-type-arg: string-prefix?
>
> Is there anything obviously wrong here?

Hmm, we’d need to see the backtrace, but it might be the fact that
‘profile-derivation’ is not bound (in the sense of >>=).

>>> Is this something we could add to the the public interface of a module?
>>
>> Sure.  For now the easiest solution would be to export ‘docker-image’
>> from (guix scripts pack).
>>
>> Longer-term, we could rename (guix docker) to (guix build docker) and
>> move ‘docker-image’ to a new (guix docker) module, but perhaps we’d also
>> need a (guix pack) modules containing tools that are shared between the
>> docker and tarball backends of ‘guix pack’.
>>
>> WDYT?
>
> It'd be nice to keep the (guix scripts ...) small, and only do
> command-line handling.  So I think a (guix build docker), and a (guix
> pack) module would be good.

Yes, I agree that this is the right direction.

Ludo’.