utils: Add toml-file.

* modules/rosenthal/utils/file.scm (toml-file): New procedure.
* modules/rosenthal/services/web.scm (conduit-shepherd, iocaine-etc)
(navidrome-shepherd-service): Use it.

modules/rosenthal/packages/guile-xyz.scm

@@ -0,0 +1,47 @@
+;;; SPDX-License-Identifier: GPL-3.0-or-later
+;;; Copyright © 2026 Hilton Chain <hako@ultrarare.space>
+
+(define-module (rosenthal packages guile-xyz)
+  ;; Utilities
+  #:use-module (guix gexp)
+  #:use-module ((guix licenses) #:prefix license:)
+  #:use-module (guix packages)
+  #:use-module (rosenthal utils packages)
+  ;; Guix origin methods
+  #:use-module (guix git-download)
+  ;; Guix build systems
+  #:use-module (guix build-system guile)
+  ;; Guix packages
+  #:use-module (gnu packages guile)
+  #:use-module (gnu packages guile-xyz))
+
+(define-public guile-toml
+  (let ((commit "ecb24deb407ef76ef7cf7e9f0115060c98366a6b")
+        (revision "0"))
+    (package
+      (name "guile-toml")
+      (version (git-version "0.0.0" revision commit))
+      (source (origin
+                (method git-fetch)
+                (uri (git-reference
+                       (url "https://github.com/hylophile/guile-toml")
+                       (commit commit)))
+                (file-name (git-file-name name version))
+                (sha256
+                 (base32
+                  "1iqxivxcb0dcjbd5ba3c0g3mj71b32qjxfdmljyv9r297yykfd02"))
+                (patches
+                 (rosenthal-patches "guile-toml-support-boolean.patch"))))
+      (build-system guile-build-system)
+      (arguments
+       (list #:phases
+             #~(modify-phases %standard-phases
+                 (add-after 'unpack 'avoid-test-installation
+                   (lambda _
+                     (delete-file-recursively "test"))))))
+      (native-inputs (list guile-3.0))
+      (propagated-inputs (list guile-json-4))
+      (home-page "https://github.com/hylophile/guile-toml")
+      (synopsis "TOML module for GNU Guile")
+      (description "")
+      (license license:gpl3+))))

modules/rosenthal/packages/patches/guile-toml-support-boolean.patch

@@ -0,0 +1,37 @@
+From 2f7e3c6f46233f9c9159fac61ca4121fe342107f Mon Sep 17 00:00:00 2001
+From: Hilton Chain <hako@ultrarare.space>
+Date: Thu, 26 Feb 2026 09:57:51 +0800
+Subject: [PATCH] builder: Support boolean value.
+
+* toml/builder.scm (toml-build-boolean): New procedure.
+(toml-build-value): Use it.
+---
+ toml/builder.scm | 5 ++++-
+ 1 file changed, 4 insertions(+), 1 deletion(-)
+
+diff --git a/toml/builder.scm b/toml/builder.scm
+index f6bdcea..3531c6f 100644
+--- a/toml/builder.scm
++++ b/toml/builder.scm
+@@ -74,6 +74,9 @@
+                                (else (string c))))
+                             (string->list s))))
+ 
++(define (toml-build-boolean b port)
++  (put-string port (if b "true" "false")))
++
+ (define (toml-build-string s port)
+   (define quote-type (if (or
+                           (string-contains s "\\")
+@@ -198,7 +201,7 @@
+        (scm port #:key (newline? #t) (inline? #f))
+      (cond
+       ;; ((eq? scm null) (toml-build-null port))
+-      ;; ((boolean? scm) (toml-build-boolean scm port))
++      ((boolean? scm) (toml-build-boolean scm port))
+       ;; ((symbol? scm) (toml-build-string (symbol->string scm) port))
+ 
+       ;; TODO float (nan, inf)
+-- 
+2.52.0
+

modules/rosenthal/services/web.scm

@@ -185,7 +185,7 @@ reload its configuration file."))
    (string "/var/lib/conduit")
    "")
   (config
-   file-like
+   gexp
    "")
   ;; Account
   (group-id
@@ -235,6 +235,7 @@ reload its configuration file."))
 (define conduit-shepherd
   (match-record-lambda <conduit-configuration>
       (conduit config auto-start? shepherd-provision shepherd-requirement)
+    (let ((config-file (toml-file "conduit.toml" config)))
       (list (shepherd-service
               (provision shepherd-provision)
               (requirement `(networking user-processes ,@shepherd-requirement))
@@ -245,10 +246,10 @@ reload its configuration file."))
                   #:group "conduit"
                   #:log-file "/var/log/conduit.log"
                   #:environment-variables
-                (list (string-append "CONDUIT_CONFIG=" #$config))))
+                  (list (string-append "CONDUIT_CONFIG=" #$config-file))))
               (stop #~(make-kill-destructor))
               (actions
-             (list (shepherd-configuration-action config)))))))
+               (list (shepherd-configuration-action config-file))))))))
 
 (define conduit-service-type
   (service-type
@@ -384,7 +385,7 @@ reload its configuration file."))
    (file-like iocaine)
    "")
   (config
-   file-object
+   gexp
    "")
   (log-file
    (string "/var/log/iocaine.log")
@@ -425,7 +426,7 @@ reload its configuration file."))
 (define iocaine-etc
   (match-record-lambda <iocaine-configuration>
       (config)
-    `(("iocaine/iocaine.toml" ,config))))
+    `(("iocaine/iocaine.toml" ,(toml-file "iocaine.toml" config)))))
 
 (define iocaine-shepherd-service
   (match-record-lambda <iocaine-configuration>
@@ -743,8 +744,8 @@ test its configuration file."))
   (auto-start?
    (boolean #t)
    "")
-  (extra-config
-   (string "")
+  (config
+   (gexp #~'())
    "")
   (no-serialization))
 
@@ -765,14 +766,13 @@ test its configuration file."))
 
 (define navidrome-shepherd-service
   (match-record-lambda <navidrome-configuration>
-      (navidrome ffmpeg auto-start? extra-config)
+      (navidrome ffmpeg auto-start? config)
     (let ((config-file
-           (mixed-text-file
-            "navidrome.toml"
-            "DataFolder = '/var/lib/navidrome'\n"
-            "CacheFolder = '/var/lib/navidrome/cache'\n"
-            "EnableInsightsCollector = false\n"
-            extra-config)))
+           (toml-file "navidrome.toml"
+             #~`(("DataFolder" . "/var/lib/navidrome")
+                 ("CacheFolder" . "/var/lib/navidrome/cache")
+                 ("EnableInsightsCollector" . #f)
+                 ,@#$config))))
       (list (shepherd-service
              (documentation "Run Navidrome.")
              (provision '(navidrome))

modules/rosenthal/utils/file.scm

@@ -9,12 +9,14 @@
   ;; Guix packages
   #:use-module (gnu packages guile)
   #:use-module (gnu packages guile-xyz)
+  #:use-module (rosenthal packages guile-xyz)
   #:export (computed-substitution-with-inputs
             file-content
             hidden-desktop-entry
 
             ini-file
             json-file
+            toml-file
             yaml-file))
 
 ;; XXX: ‘substitute*’ doesn't fully support Unicode:
@@ -80,6 +82,19 @@ format."
           (call-with-output-file #$output
             (cut scm->json #$exp <> #:pretty #t))))))
 
+;; https://github.com/hylophile/guile-toml
+;; TODO: TOML writing support is incomplete.
+;; See https://github.com/hylophile/guile-toml/blob/main/toml/builder.scm.
+(define (toml-file name exp)
+  "Return file-like object NAME, serialized from G-expression EXP in TOML
+format."
+  (computed-file name
+    (with-extensions (list guile-json-4 guile-toml)
+      #~(begin
+          (use-modules (srfi srfi-26) (toml))
+          (call-with-output-file #$output
+            (cut scm->toml #$exp <>))))))
+
 ;; https://gitlab.com/yorgath/guile-yamlpp
 (define (yaml-file name exp)
   "Return file-like object NAME, serialized from G-expression EXP in YAML