datetime: New module for date & time operations

- Enable/disable ntpd from this module.  Since ntpd has implications on
  anonymity.

- Implement NTP diagonstics from freedombox-setup.

- Eventually provide ability to set date & time of the system.

- Eventually move timezone configuration to this module.

actions/datetime

@@ -0,0 +1,60 @@
+#!/usr/bin/python3
+# -*- mode: python -*-
+#
+# This file is part of Plinth.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+"""
+Configuration helper for date and time
+"""
+
+import argparse
+
+from plinth import action_utils
+
+
+def parse_arguments():
+    """Return parsed command line arguments as dictionary."""
+    parser = argparse.ArgumentParser()
+    subparsers = parser.add_subparsers(dest='subcommand', help='Sub command')
+
+    subparsers.add_parser('enable', help='Enable NTP service')
+    subparsers.add_parser('disable', help='Disable NTP service')
+
+    return parser.parse_args()
+
+
+def subcommand_enable(_):
+    """Start service."""
+    action_utils.service_enable('ntp')
+
+
+def subcommand_disable(_):
+    """Stop service."""
+    action_utils.service_disable('ntp')
+
+
+def main():
+    """Parse arguments and perform all duties."""
+    arguments = parse_arguments()
+
+    subcommand = arguments.subcommand.replace('-', '_')
+    subcommand_method = globals()['subcommand_' + subcommand]
+    subcommand_method(arguments)
+
+
+if __name__ == '__main__':
+    main()

data/etc/plinth/modules-enabled/datetime

@@ -0,0 +1 @@
+plinth.modules.datetime

plinth/modules/datetime/__init__.py

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+#
+# This file is part of Plinth.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+"""
+Plinth module to configure system date and time
+"""
+
+from gettext import gettext as _
+import subprocess
+
+from plinth import actions
+from plinth import action_utils
+from plinth import cfg
+from plinth import service as service_module
+
+
+depends = ['plinth.modules.system']
+
+service = None
+
+
+def init():
+    """Intialize the date/time module."""
+    menu = cfg.main_menu.get('system:index')
+    menu.add_urlname(_('Date & Time'), 'glyphicon-time',
+                     'datetime:index', 900)
+
+    global service
+    service = service_module.Service(
+        'ntp', _('Network Time Server'),
+        is_external=False, enabled=is_enabled())
+
+
+def is_enabled():
+    """Return whether the module is enabled."""
+    return action_utils.service_is_enabled('ntp')
+
+
+def is_running():
+    """Return whether the service is running."""
+    return action_utils.service_is_running('ntp')
+
+
+def diagnose():
+    """Run diagnostics and return the results."""
+    results = []
+    results.append(_diagnose_ntp_server_count())
+
+    return results
+
+
+def _diagnose_ntp_server_count():
+    """Diagnose minimum NTP server count."""
+    result = 'failed'
+    try:
+        output = subprocess.check_output(['ntpq', '-n', '-c', 'lpeers'])
+        if len(output.decode().splitlines()[2:]):
+            result = 'passed'
+    except subprocess.CalledProcessError:
+        pass
+
+    return [_('NTP client in contact with servers'), result]

plinth/modules/datetime/forms.py

@@ -0,0 +1,30 @@
+#
+# This file is part of Plinth.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+"""
+Forms for configuring date and time
+"""
+
+from django import forms
+from gettext import gettext as _
+
+
+class DateTimeForm(forms.Form):
+    """Date/time configuration form."""
+    enabled = forms.BooleanField(
+        label=_('Enable network time'),
+        required=False)

plinth/modules/datetime/templates/datetime.html

@@ -0,0 +1,50 @@
+{% extends "base.html" %}
+{% comment %}
+#
+# This file is part of Plinth.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+{% endcomment %}
+
+{% load bootstrap %}
+
+{% block content %}
+
+<h2>Date & Time</h2>
+
+<p>Network time server is a program that maintians the system time in synchronization with servers on the Internet.</p>
+
+<h3>Status</h3>
+
+<p class="running-status-parent">
+  {% if status.is_running %}
+  <span class="running-status active"></span> Network time server is running
+  {% else %}
+  <span class="running-status inactive"></span> Network time server is not running
+  {% endif %}
+</p>
+{% include "diagnostics_button.html" with module="datetime" %}
+
+<h3>Configuration</h3>
+
+<form class="form" method="post">
+  {% csrf_token %}
+
+  {{ form|bootstrap }}
+
+  <input type="submit" class="btn btn-primary" value="Update setup"/>
+</form>
+
+{% endblock %}

plinth/modules/datetime/urls.py

@@ -0,0 +1,28 @@
+#
+# This file is part of Plinth.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+"""
+URLs for the date and time module
+"""
+
+from django.conf.urls import patterns, url
+
+
+urlpatterns = patterns(
+    'plinth.modules.datetime.views',
+    url(r'^sys/datetime/$', 'index', name='index'),
+    )

plinth/modules/datetime/views.py

@@ -0,0 +1,82 @@
+#
+# This file is part of Plinth.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+"""
+Plinth module for configuring date and time
+"""
+
+from django.contrib import messages
+from django.template.response import TemplateResponse
+from gettext import gettext as _
+import logging
+
+from .forms import DateTimeForm
+from plinth import actions
+from plinth import package
+from plinth.modules import datetime
+
+logger = logging.getLogger(__name__)
+
+
+def on_install():
+    """Notify that the service is now enabled."""
+    datetime.service.notify_enabled(None, True)
+
+
+@package.required(['ntp'])
+def index(request):
+    """Serve configuration page."""
+    status = get_status()
+
+    form = None
+
+    if request.method == 'POST':
+        form = DateTimeForm(request.POST, prefix='datetime')
+        # pylint: disable=E1101
+        if form.is_valid():
+            _apply_changes(request, status, form.cleaned_data)
+            status = get_status()
+            form = DateTimeForm(initial=status, prefix='datetime')
+    else:
+        form = DateTimeForm(initial=status, prefix='datetime')
+
+    return TemplateResponse(request, 'datetime.html',
+                            {'title': _('Voice Chat (Datetime)'),
+                             'status': status,
+                             'form': form})
+
+
+def get_status():
+    """Get the current settings from server."""
+    return {'enabled': datetime.is_enabled(),
+            'is_running': datetime.is_running()}
+
+
+def _apply_changes(request, old_status, new_status):
+    """Apply the changes."""
+    modified = False
+
+    if old_status['enabled'] != new_status['enabled']:
+        sub_command = 'enable' if new_status['enabled'] else 'disable'
+        actions.superuser_run('datetime', [sub_command])
+        datetime.service.notify_enabled(None, new_status['enabled'])
+        modified = True
+
+    if modified:
+        messages.success(request, _('Configuration updated'))
+    else:
+        messages.info(request, _('Setting unchanged'))