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From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: Composing service definitions (and maybe fmt)
Date: Thu, 21 Jan 2016 22:27:45 +0100
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	(David Thompson's message of "Thu, 21 Jan 2016 09:12:49 -0500")
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To: "Thompson, David" <dthompson2@worcester.edu>
Cc: guix-devel <guix-devel@gnu.org>

"Thompson, David" <dthompson2@worcester.edu> skribis:

> On Wed, Jan 20, 2016 at 5:13 PM, Ludovic Court=C3=A8s <ludo@gnu.org> wrot=
e:
>
>> To me, the question is more about choosing between writing configuration
>> file bindings and exposing upstream=E2=80=99s configuration file syntax,=
 as was
>> discussed when Andy posted the Dovecot service.  (To which I don=E2=80=
=99t have
>> a better answer than: let=E2=80=99s see on a case-by-case basis.)
>
> How about this:
>
> Procedures that return services should accept file-like objects when
> configuration files are needed.  When it makes sense (like with
> elogind, dovecot, etc.), we can provide special procedures that take a
> Scheme data structure and "compile" that to a file-like object in the
> service's native configuration language.  This way, we allow ourselves
> to have the high-level Scheme configuration APIs we like while also
> allowing the use of "raw" configuration files in situations where it
> is unavoidable or the path of least resistance.

I like it!  When we provide Scheme data structures, we necessarily have
a =E2=80=98foo-configuration->file=E2=80=99 procedure anyway, so it=E2=80=
=99s just a matter of
exposing it.

Ludo=E2=80=99.