gnu: home: services: Add home-znc-service-type.

* gnu/home/services/messaging.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add it.
* po/guix/POTFILES.in: Likewise.
* doc/guix.texi (Messaging Home Services): Document it in new subsection.

gnu/home/services/messaging.scm

@@ -0,0 +1,73 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2023 Janneke Nieuwenhuizen <janneke@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu home services messaging)
+  #:use-module (srfi srfi-26)
+
+  #:use-module (ice-9 match)
+
+  #:use-module (shepherd support)
+
+  #:use-module (gnu home services)
+  #:use-module (gnu home services shepherd)
+  #:use-module (gnu packages messaging)
+  #:use-module (gnu services configuration)
+  #:use-module (gnu services shepherd)
+  #:use-module (guix records)
+  #:use-module (guix gexp)
+
+  #:export (home-znc-configuration
+            home-znc-service-type))
+
+;;;
+;;; Znc.
+;;;
+(define-record-type* <home-znc-configuration>
+  home-znc-configuration make-home-znc-configuration
+  home-znc-configuration?
+  (znc           home-znc-znc           ;string
+                 (default znc))
+  (extra-options home-znc-extra-options ;list of string
+                 (default '())))
+
+(define (home-znc-services config)
+  "Return a <shepherd-service> for znc with CONFIG."
+  (match config
+    (($ <home-znc-configuration> znc extra-options)
+     (let* ((znc (file-append znc "/bin/znc"))
+            (command `(,znc
+                       "--foreground"
+                       ,@extra-options))
+            (log-file (string-append %user-log-dir "/znc.log")))
+       (list (shepherd-service
+              (documentation "Run the znc IRC bouncer.")
+              (provision '(znc))
+              (start #~(make-forkexec-constructor '#$command
+                                                  #:log-file #$log-file))
+              (stop #~(make-kill-destructor))))))))
+
+(define home-znc-service-type
+  (service-type
+   (name 'home-znc)
+   (default-value (home-znc-configuration))
+   (extensions
+    (list (service-extension home-shepherd-service-type
+                             home-znc-services)))
+   (description
+    "Install and configure @command{znc}, an @acronym{IRC, Internet Relay
+Chat} bouncer, as a Shepherd service.")))