letsencrypt: Implement DBus service for renewal notifications

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: Joseph Nuthalapati <njoseph@thoughtworks.com>

plinth/dbus.py

@@ -100,6 +100,10 @@ class DBusServer():
         self.package_handler = PackageHandler()
         self.package_handler.register(connection)
 
+        from plinth.modules.letsencrypt.dbus import LetsEncrypt
+        lets_encrypt = LetsEncrypt()
+        lets_encrypt.register(connection)
+
     @staticmethod
     def on_name_acquired(_connection, name):
         """Callback when service name on D-Bus has been acquired."""

plinth/modules/letsencrypt/dbus.py

@@ -0,0 +1,78 @@
+#
+# This file is part of FreedomBox.
+#
+# 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/>.
+#
+"""
+Expose API over D-Bus to receive renewal notifications.
+"""
+
+import logging
+
+from plinth.utils import import_from_gi
+
+gio = import_from_gi('Gio', '2.0')
+
+logger = logging.getLogger(__name__)
+
+
+class LetsEncrypt:
+    """D-Bus service to listen for Let's Encrypt renewal notifications."""
+
+    introspection_xml = '''
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
+  "http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
+<node name="/org/freedombox/Service/LetsEncrypt">
+  <interface name="org.freedombox.Service.LetsEncrypt">
+    <method name="DeployHook">
+      <arg name="renewed_domains" type="s" direction="in"/>
+      <arg name="renewed_lineage" type="s" direction="in"/>
+    </method>
+  </interface>
+</node>
+'''
+
+    def register(self, connection):
+        """Register the object in D-Bus connection."""
+        introspection_data = gio.DBusNodeInfo.new_for_xml(
+            self.introspection_xml)
+        interface_info = gio.DBusNodeInfo.lookup_interface(
+            introspection_data, 'org.freedombox.Service.LetsEncrypt')
+        connection.register_object('/org/freedombox/Service/LetsEncrypt',
+                                   interface_info, self.on_method_call, None,
+                                   None)
+
+    def on_method_call(self, _connection, _sender, _object_path,
+                       _interface_name, method_name, parameters, invocation):
+        """Handle method being called.
+
+        No need to check all the incoming parameters as D-Bus will validate all
+        the incoming parameters using introspection data.
+
+        """
+        if method_name == 'DeployHook':
+            self._on_deploy_hook(parameters[0], parameters[1])
+            invocation.return_value()
+
+    @staticmethod
+    def _on_deploy_hook(renewed_domains, renewed_lineage):
+        """Run renewal hooks for each app.
+
+        Don't run this a new thread here because
+        component.on_certificate_event() creates one anyway.
+
+        """
+        logger.info('LE certificate renewed (deployed): %s, %s.',
+                    renewed_domains, renewed_lineage)