T5374: Add system option time-format 12 or 24 hours

Ability to set locate time format 12|24-hour

set system option time-format 12-hour|24-hour

$ date
Tue Aug  1 12:33:45 PM EEST 2023

$ date
Tue  1 Aug 12:34:09 EEST 2023

2 files changed, 31 insertions, 1 deletions

diff --git a/interface-definitions/system-option.xml.in b/interface-definitions/system-option.xml.in
index efab50a66..b1b5f7fae 100644
--- a/interface-definitions/system-option.xml.in
+++ b/interface-definitions/system-option.xml.in
@@ -144,6 +144,26 @@
                <valueless/>
              </properties>
            </leafNode>
+           <leafNode name="time-format">
+            <properties>
+              <help>System time-format</help>
+              <completionHelp>
+                <list>12-hour 24-hour</list>
+              </completionHelp>
+              <valueHelp>
+                <format>12-hour</format>
+                <description>12 hour time format</description>
+              </valueHelp>
+              <valueHelp>
+                <format>24-hour</format>
+                <description>24 hour time format</description>
+              </valueHelp>
+              <constraint>
+                <regex>(12-hour|24-hour)</regex>
+              </constraint>
+            </properties>
+            <defaultValue>12-hour</defaultValue>
+           </leafNode>
         </children>
       </node>
     </children>
diff --git a/src/conf_mode/system-option.py b/src/conf_mode/system-option.py
index 5172b492e..1495e9223 100755
--- a/src/conf_mode/system-option.py
+++ b/src/conf_mode/system-option.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2019-2022 VyOS maintainers and contributors
+# Copyright (C) 2019-2023 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -36,6 +36,11 @@ airbag.enable()
 curlrc_config = r'/etc/curlrc'
 ssh_config = r'/etc/ssh/ssh_config.d/91-vyos-ssh-client-options.conf'
 systemd_action_file = '/lib/systemd/system/ctrl-alt-del.target'
+time_format_to_locale = {
+    '12-hour': 'en_US.UTF-8',
+    '24-hour': 'en_GB.UTF-8'
+}
+
 
 def get_config(config=None):
     if config:
@@ -143,6 +148,11 @@ def apply(options):
     else:
       cmd('systemctl disable root-partition-auto-resize.service')
 
+    # Time format 12|24-hour
+    if 'time_format' in options:
+        time_format = time_format_to_locale.get(options['time_format'])
+        cmd(f'localectl set-locale LC_TIME={time_format}')
+
 if __name__ == '__main__':
     try:
         c = get_config()