services: Add radicale-service-type.

* gnu/services/mail.scm (radicale-configuration)
(radicale-configuration?): New procedures.
(%default-radicale-config-file)
(radicale-service-type): New variables.
* doc/guix.texi: Document it.

doc/guix.texi

@@ -85,6 +85,7 @@ Copyright @copyright{} 2020 Alexandru-Sergiu Marton@*
 Copyright @copyright{} 2020 raingloom@*
 Copyright @copyright{} 2020 Daniel Brooks@*
 Copyright @copyright{} 2020 John Soo@*
+Copyright @copyright{} 2020 Jonathan Brielmaier@*
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
@@ -21217,6 +21218,30 @@ Mailutils Manual}, for details.
 @end table
 @end deftp
 
+@subsubheading Radicale Service
+@cindex CalDAV
+@cindex CardDAV
+
+@deffn {Scheme Variable} radicale-service-type
+This is the type of the @uref{https://radicale.org, Radicale} CalDAV/CardDAV
+server whose value should be a @code{radicale-configuration}.
+@end deffn
+
+@deftp {Data Type} radicale-configuration
+Data type representing the configuration of @command{radicale}.
+
+@table @asis
+@item @code{package} (default: @code{radicale})
+The package that provides @command{radicale}.
+
+@item @code{config-file} (default: @code{%default-radicale-config-file})
+File-like object of the configuration file to use, by default it will listen
+on TCP port 5232 of @code{localhost} and use the @code{htpasswd} file at
+@file{/var/lib/radicale/users} with no (@code{plain}) encryption.
+
+@end table
+@end deftp
+
 @node Messaging Services
 @subsection Messaging Services
 

gnu/services/mail.scm

@@ -4,6 +4,7 @@
 ;;; Copyright © 2017 Carlo Zancanaro <carlo@zancanaro.id.au>
 ;;; Copyright © 2017, 2020 Tobias Geerinckx-Rice <me@tobias.gr>
 ;;; Copyright © 2019 Kristofer Buffington <kristoferbuffington@gmail.com>
+;;; Copyright © 2020 Jonathan Brielmaier <jonathan.brielmaier@web.de>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -31,6 +32,7 @@
   #:use-module (gnu system shadow)
   #:use-module (gnu packages mail)
   #:use-module (gnu packages admin)
+  #:use-module (gnu packages dav)
   #:use-module (gnu packages tls)
   #:use-module (guix records)
   #:use-module (guix packages)
@@ -70,7 +72,12 @@
             imap4d-configuration
             imap4d-configuration?
             imap4d-service-type
-            %default-imap4d-config-file))
+            %default-imap4d-config-file
+
+            radicale-configuration
+            radicale-configuration?
+            radicale-service-type
+            %default-radicale-config-file))
 
 ;;; Commentary:
 ;;;
@@ -1834,3 +1841,75 @@ exim_group = exim
     (list (service-extension
            shepherd-root-service-type imap4d-shepherd-service)))
    (default-value (imap4d-configuration))))
+
+
+;;;
+;;; Radicale.
+;;;
+
+(define-record-type* <radicale-configuration>
+  radicale-configuration make-radicale-configuration
+  radicale-configuration?
+  (package     radicale-configuration-package
+               (default radicale))
+  (config-file radicale-configuration-config-file
+               (default %default-radicale-config-file)))
+
+(define %default-radicale-config-file
+  (plain-file "radicale.conf" "
+[auth]
+type = htpasswd
+htpasswd_filename = /var/lib/radicale/users
+htpasswd_encryption = plain
+
+[server]
+hosts = localhost:5232"))
+
+(define %radicale-accounts
+  (list (user-group
+         (name "radicale")
+         (system? #t))
+        (user-account
+         (name "radicale")
+         (group "radicale")
+         (system? #t)
+         (comment "Radicale Daemon")
+         (home-directory "/var/empty")
+         (shell (file-append shadow "/sbin/nologin")))))
+
+(define radicale-shepherd-service
+  (match-lambda
+    (($ <radicale-configuration> package config-file)
+     (list (shepherd-service
+            (provision '(radicale))
+            (documentation "Run the radicale daemon.")
+            (requirement '(networking))
+            (start #~(make-forkexec-constructor
+                      (list #$(file-append package "/bin/radicale")
+                        "-C" #$config-file)
+                      #:user "radicale"
+                      #:group "radicale"))
+            (stop #~(make-kill-destructor)))))))
+
+(define radicale-activation
+  (match-lambda
+    (($ <radicale-configuration> package config-file)
+     (with-imported-modules '((guix build utils))
+       #~(begin
+           (use-modules (guix build utils))
+           (let ((uid (passwd:uid (getpw "radicale")))
+                 (gid (group:gid (getgr "radicale"))))
+             (mkdir-p "/var/lib/radicale/collections")
+             (chown "/var/lib/radicale" uid gid)
+             (chown "/var/lib/radicale/collections" uid gid)
+             (chmod "/var/lib/radicale" #o700)))))))
+
+(define radicale-service-type
+  (service-type
+   (name 'radicale)
+   (description "Run radicale, a small CalDAV and CardDAV server.")
+   (extensions
+    (list (service-extension shepherd-root-service-type radicale-shepherd-service)
+          (service-extension account-service-type (const %radicale-accounts))
+          (service-extension activation-service-type radicale-activation)))
+   (default-value (radicale-configuration))))