config: Migrate default app configuration to new conf file

Signed-off-by: Joseph Nuthalapati <njoseph@thoughtworks.com>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

actions/config

@@ -23,8 +23,11 @@ Configuration helper for FreedomBox general configuration.
 import argparse
 import os
 
+import augeas
+
 from plinth import action_utils
-from plinth.modules.config import DEFAULT_APP_CONF_FILE_NAME
+from plinth.modules.config import (DEFAULT_APP_CONF_FILE_NAME,
+                                   FREEDOMBOX_APACHE_CONFIG)
 
 
 def parse_arguments():
@@ -35,11 +38,31 @@ def parse_arguments():
         'set-default-app',
         help='Set the default app for this FreedomBox instance.')
     set_default_app.add_argument('app', help='name of the default app')
+    subparsers.add_parser(
+        'reset-default-app',
+        help='Reset the default app configuraton in freedombox.conf')
 
     subparsers.required = True
     return parser.parse_args()
 
 
+def subcommand_reset_default_app(_):
+    aug = augeas.Augeas(flags=augeas.Augeas.NO_LOAD +
+                        augeas.Augeas.NO_MODL_AUTOLOAD)
+    aug.set('/augeas/load/Httpd/lens', 'Httpd.lns')
+    aug.set('/augeas/load/Httpd/incl[last() + 1]', FREEDOMBOX_APACHE_CONFIG)
+    aug.load()
+
+    aug.defvar('conf', '/files' + FREEDOMBOX_APACHE_CONFIG)
+
+    for match in aug.match('/files' + FREEDOMBOX_APACHE_CONFIG +
+                           '/directive["RedirectMatch"]'):
+        if aug.get(match + "/arg[1]") == '''"^/$"''':
+            aug.set(match + "/arg[2]", '"/{}"'.format('plinth'))
+
+    aug.save()
+
+
 def subcommand_set_default_app(arguments):
     """Set the default app for this FreedomBox."""
     conf_file_path = os.path.join('/etc/apache2/conf-available',

plinth/modules/config/__init__.py

@@ -30,7 +30,7 @@ from plinth.modules import firewall
 from plinth.modules.names import SERVICES
 from plinth.signals import domain_added
 
-version = 1
+version = 2
 
 is_essential = True
 
@@ -74,6 +74,8 @@ def get_default_app():
         if aug.get(match + "/arg[1]") == '''"^/$"''':
             app_path = aug.get(match + "/arg[2]")
 
+    # match this against the app_id in the entries of frontpage.get_shortcuts()
+    # The underscore is to handle Ikiwiki app_ids
     return app_path.strip('/"').replace('/', '_')
 
 
@@ -100,3 +102,22 @@ def init():
                                  name=domainname,
                                  description=ugettext_lazy('Domain Name'),
                                  services=domainname_services)
+
+
+def setup(helper, old_version=None):
+    """Install and configure the module."""
+    _migrate_default_app_config()
+
+
+def _migrate_default_app_config():
+    """Move the default app configuration to an external file."""
+
+    # Hold the current default app in a variable
+    default_app_path = get_default_app().replace('_', '/')
+
+    # Reset the default app to plinth in freedombox.conf
+    actions.superuser_run('config', ['reset-default-app'])
+
+    # Write the default app setting into the new conf file
+    # This step is run at the end because it reloads the Apache server
+    actions.superuser_run('config', ['set-default-app', default_app_path])