quassel: Enable backup/restore

- All the configuration is in data folder, no custom configuration.

- SSL certificate is in the data folder.

- Users, logs etc. are in sqlite file in the data folder.

Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

functional_tests/features/quassel.feature

@@ -32,3 +32,11 @@ Scenario: Disable quassel application
   Given the quassel application is enabled
   When I disable the quassel application
   Then the quassel service should not be running
+
+# TODO: Improve this to actually check that data configured servers is restored.
+Scenario: Backup and restore quassel
+  Given the quassel application is enabled
+  When I create a backup of the quassel app data
+  And I export the quassel app data backup
+  And I restore the quassel app data backup
+  Then the quassel service should be running

plinth/modules/quassel/__init__.py

@@ -27,7 +27,7 @@ from plinth.menu import main_menu
 from plinth.utils import format_lazy
 from plinth.views import ServiceView
 
-from .manifest import clients
+from .manifest import backup, clients
 
 version = 1
 

plinth/modules/quassel/manifest.py

@@ -18,6 +18,7 @@
 from django.utils.translation import ugettext_lazy as _
 
 from plinth.clients import store_url, validate
+from plinth.modules.backups.api import validate as validate_backup
 
 clients = validate([{
     'name':
@@ -58,3 +59,10 @@ clients = validate([{
         'url': store_url('google-play', 'com.iskrembilen.quasseldroid'),
     }]
 }])
+
+backup = validate_backup({
+    'secrets': {
+        'directories': ['/var/lib/quassel/']
+    },
+    'services': ['quassel-core'],
+})