Subject: [bug#62298] [PATCH v2 8/8] services: mympd: Use user-account (resp. user-group) for user (resp. group) fields.

From: Maxim Cournoyer <[email-masked]>
Date: Fri, 24 Mar 2023 12:03:09 -0400

Hello,

Bruno Victal <[email-masked]> writes:

> services: mympd: Use user-account (resp. user-group) for user (resp. group) fields.
>
> * gnu/services/audio.scm (%mympd-user, %mympd-group): New variable.
> (mympd-user-sanitizer, mympd-group-sanitizer): New procedure.
> (mympd-configuration)[user, group]: Set value type to user-account (resp. user-group).
> (mympd-serialize-configuration): Adapt for user-account values in user field.
> (mympd-accounts): Adapt for user-account (resp. user-group) in user (resp. group) field.

Please configure your editor for the 80 characters mark.

> ---
>  doc/guix.texi          |  4 +--
>  gnu/services/audio.scm | 74 ++++++++++++++++++++++++++++++++++--------
>  2 files changed, 63 insertions(+), 15 deletions(-)
>
> diff --git a/doc/guix.texi b/doc/guix.texi
> index 520a65b0b1..ee1e66b3ff 100644
> --- a/doc/guix.texi
> +++ b/doc/guix.texi
> @@ -33732,10 +33732,10 @@ Audio Services
>  This is a list of symbols naming Shepherd services that this service
>  will depend on.
>  
> -@item @code{user} (default: @code{"mympd"}) (type: string)
> +@item @code{user} (type: maybe-user-account)
>  Owner of the @command{mympd} process.
>  
> -@item @code{group} (default: @code{"nogroup"}) (type: string)
> +@item @code{group} (type: maybe-user-group)
>  Owner group of the @command{mympd} process.
>  
>  @item @code{work-directory} (default: @code{"/var/lib/mympd"}) (type: string)
> diff --git a/gnu/services/audio.scm b/gnu/services/audio.scm
> index c168d1481c..f7f430039e 100644
> --- a/gnu/services/audio.scm
> +++ b/gnu/services/audio.scm
> @@ -659,6 +659,54 @@ (define-configuration/no-serialization mympd-ip-acl
>  (define-maybe/no-serialization integer)
>  (define-maybe/no-serialization mympd-ip-acl)
>  
> +;; XXX: These will shadow the previous definition used by mpd
> +;;      and cause warnings to be shown. Maybe split the file
> +;;      into audio/mpd.scm and audio/mympd.scm ?
> +#;(define-maybe/no-serialization user-account)
> +#;(define-maybe/no-serialization user-group)

I'd rather keeping them together if possible; could the prefix trick be
used with them?  No need for a hanging indent for continued text, here
and for the other occurrences.

The expressions commented; should they be?  On another note, '#;'
appears undocumented, I'd avoid it until it is (and it's not necessary
here).

> +(define %mympd-user
> +  (user-account
> +      (name "mympd")
> +      (group "mympd")
> +      (system? #t)
> +      (comment "myMPD user")
> +      (home-directory "/var/empty")
> +      (shell (file-append shadow "/sbin/nologin"))))
> +
> +(define %mympd-group
> +  (user-group
> +   (name "mympd")
> +   (system? #t)))
> +
> +;;; TODO: procedures for unsupported value types, to be removed.
             ^ Procedures
             
> +(define (mympd-user-sanitizer value)
> +  (cond ((user-account? value) value)
> +        ((string? value)
> +         (warning (G_ "string value for 'user' is not supported, use \
> +user-account instead~%"))
> +         (user-account
> +          (inherit %mympd-user)
> +          (name value)
> +          ;; XXX: this is to be lazily substituted in (…-accounts)
> +          ;;      with the value from 'group'.

Extraneous hanging indent :-).

> +          (group %lazy-group)))
> +        (else
> +         (configuration-field-error #f 'user value))))
> +
> +(define (mympd-group-sanitizer value)
> +  (cond ((user-group? value) value)
> +        ((string? value)
> +         (warning (G_ "string value for 'group' is not supported, use \
> +user-group instead~%"))
> +         (user-group
> +          (inherit %mympd-group)
> +          (name value)))
> +        (else
> +         (configuration-field-error #f 'group value))))
> +;;;

Was this ';;;' added by mistake?

>  ;; XXX: The serialization procedures are insufficient since we require
>  ;; access to multiple fields at once.
>  ;; Fields marked with empty-serializer are never serialized and are
> @@ -676,13 +724,15 @@ (define-configuration/no-serialization mympd-configuration
>     empty-serializer)
>  
>    (user
> -   (string "mympd")
> +   (maybe-user-account %mympd-user)
>     "Owner of the @command{mympd} process."
> +   (sanitizer mympd-user-sanitizer)
>     empty-serializer)
>  
>    (group
> -   (string "nogroup")
> +   (maybe-user-group %mympd-group)
>     "Owner group of the @command{mympd} process."
> +   (sanitizer mympd-group-sanitizer)
>     empty-serializer)
>  
>    (work-directory
> @@ -817,7 +867,8 @@ (define (mympd-shepherd-service config)
>    (match-record config <mympd-configuration> (package shepherd-requirement
>                                                user work-directory
>                                                cache-directory log-level log-to)
> -    (let ((log-level* (format #f "MYMPD_LOGLEVEL=~a" log-level)))
> +    (let ((log-level* (format #f "MYMPD_LOGLEVEL=~a" log-level))
> +          (username (user-account-name user)))
>        (shepherd-service
>         (documentation "Run the myMPD daemon.")
>         (requirement `(loopback user-processes
> @@ -825,7 +876,7 @@ (define (mympd-shepherd-service config)
>                                 ,@shepherd-requirement))
>         (provision '(mympd))
>         (start #~(begin
> -                  (let* ((pw (getpwnam #$user))
> +                  (let* ((pw (getpwnam #$username))
>                           (uid (passwd:uid pw))
>                           (gid (passwd:gid pw)))
>                      (for-each (lambda (dir)
> @@ -835,7 +886,7 @@ (define (mympd-shepherd-service config)
>  
>                    (make-forkexec-constructor
>                     `(#$(file-append package "/bin/mympd")
> -                     "--user" #$user
> +                     "--user" #$username
>                       #$@(if (eqv? log-to 'syslog) '("--syslog") '())
>                       "--workdir" #$work-directory
>                       "--cachedir" #$cache-directory)
> @@ -845,14 +896,11 @@ (define (mympd-shepherd-service config)
>  
>  (define (mympd-accounts config)
>    (match-record config <mympd-configuration> (user group)
> -                (list (user-group (name group)
> -                                  (system? #t))
> -                      (user-account (name user)
> -                                    (group group)
> -                                    (system? #t)
> -                                    (comment "myMPD user")
> -                                    (home-directory "/var/empty")
> -                                    (shell (file-append shadow "/sbin/nologin"))))))
> +    ;; TODO: deprecation code, to be removed

Please use a full sentence.

> +    (let ((user (if (eq? (user-account-group user) %lazy-group)
> +                    (inject-group-into-user user group)
> +                    user)))
> +      (list user group))))
>  
>  (define (mympd-log-rotation config)
>    (match-record config <mympd-configuration> (log-to)

LGTM, with the comments from Liliana taken into account.

-- 
Thanks,
Maxim