Re: Add a way to disable serialization support to (guix services configuration)

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hi,

Xinglu Chen <public@yoctocell.xyz> writes:

[...]

> From 90d63a46a29a8080b7f95eabcec115c5c2c6481e Mon Sep 17 00:00:00 2001
> Message-Id: <90d63a46a29a8080b7f95eabcec115c5c2c6481e.1619869705.git.public@yoctocell.xyz>
> In-Reply-To: <cover.1619869705.git.public@yoctocell.xyz>
> References: <cover.1619869705.git.public@yoctocell.xyz>
> From: Xinglu Chen <public@yoctocell.xyz>
> Date: Sat, 1 May 2021 13:31:27 +0200
> Subject: [PATCH 2/2] services: configuration: Add ability to use custom
>  serializer.
> MIME-Version: 1.0
> Content-Type: text/plain; charset=UTF-8
> Content-Transfer-Encoding: 8bit
>
> Some configuration values should not be serialized to a configuration file,
> e.g. command line options for a daemon.
>
> * gnu/services/configuration.scm (define-configuration): Add option to use a
> custom serializer.
> (empty-serializer): New procedure.
> (serialize-package): Alias to ‘empty-serializer’.
> ---
>  gnu/services/configuration.scm | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/gnu/services/configuration.scm b/gnu/services/configuration.scm
> index 85e1ac78cb..7024b13136 100644
> --- a/gnu/services/configuration.scm
> +++ b/gnu/services/configuration.scm
> @@ -44,6 +44,7 @@
>              define-configuration
>              validate-configuration
>              generate-documentation
> +            empty-serializer
>              serialize-package))
>  
>  ;;; Commentary:
> @@ -116,7 +117,7 @@
>  (define-syntax define-configuration
>    (lambda (stx)
>      (syntax-case stx ()
> -      ((_ stem (field (field-type properties ...) doc) ...)
> +      ((_ stem (field (field-type properties ...) doc custom-serializer ...) ...)
>         (with-syntax (((field-getter ...)
>                        (map (lambda (field)
>                               (id #'stem #'stem #'- field))
> @@ -133,9 +134,12 @@
>                               (_ (syntax 'disabled)))
>                             #'((field-type properties ...) ...)))
>                       ((field-serializer ...)
> -                      (map (lambda (type)
> -                             (id #'stem #'serialize- type))
> -                           #'(field-type ...))))
> +                      (map (lambda (type serializer)
> +                             (match serializer
> +                               (((serializer)) serializer)
> +                               (_ (id #'stem #'serialize- type))))
> +                           #'(field-type ...)
> +                           #'((custom-serializer ...) ...))))
>           #`(begin
>               (define-record-type* #,(id #'stem #'< #'stem #'>)
>                 #,(id #'stem #'% #'stem)
> @@ -176,8 +180,8 @@
>                                           #,(id #'stem #'stem #'-fields))
>                   conf))))))))
>  
> -(define (serialize-package field-name val)
> -  "")
> +(define (empty-serializer field-name val) "")
> +(define serialize-package empty-serializer)
>  
>  ;; A little helper to make it easier to document all those fields.
>  (define (generate-documentation documentation documentation-name)

Rebased on a change that allows to globally (at the configuration level)
disable serialization and pushed as b3e99d3399.

Thank you! :-)

Maxim