config: Reset home page setting in freedombox.conf during migration

While moving the home page configuration to a new file, also reset the home page
path in freedombox.conf to its default setting of /plinth.

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

actions/config

@@ -23,6 +23,8 @@ Configuration helper for FreedomBox general configuration.
 import argparse
 import os
 
+import augeas
+
 from plinth import action_utils
 from plinth.modules.config import APACHE_HOMEPAGE_CONF_FILE_NAME
 
@@ -31,12 +33,19 @@ def parse_arguments():
     """Return parsed command line arguments as dictionary."""
     parser = argparse.ArgumentParser()
     subparsers = parser.add_subparsers(dest='subcommand', help='Sub command')
+
     set_home_page = subparsers.add_parser(
         'set-home-page',
         help='Set the home page for this FreedomBox instance.')
     set_home_page.add_argument('homepage',
                                help='path to the webserver home page')
 
+    reset_home_page = subparsers.add_parser(
+        'reset-home-page', help='Reset the homepage of the Apache server.')
+    reset_home_page.add_argument(
+        '--config', default=APACHE_HOMEPAGE_CONF_FILE_NAME,
+        help='(optional) path to the Apache config file')
+
     subparsers.required = True
     return parser.parse_args()
 
@@ -54,6 +63,30 @@ def subcommand_set_home_page(arguments):
     action_utils.webserver_enable('freedombox-apache-homepage')
 
 
+def subcommand_reset_home_page(arguments):
+    """Sets the Apache web server's home page to the default - /plinth
+
+    The config file path can be optionally passed as an argument.
+    """
+    config_file = arguments.config
+    default_path = 'plinth'
+
+    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]', config_file)
+    aug.load()
+
+    aug.defvar('conf', '/files' + config_file)
+
+    for match in aug.match('/files' + config_file +
+                           '/directive["RedirectMatch"]'):
+        if aug.get(match + "/arg[1]") == '''"^/$"''':
+            aug.set(match + "/arg[2]", '"/{}"'.format(default_path))
+
+    aug.save()
+
+
 def main():
     """Parse arguments and perform all duties."""
     arguments = parse_arguments()

plinth/modules/config/__init__.py

@@ -59,8 +59,8 @@ def get_hostname():
 
 def get_home_page():
     """Get the default application for the domain."""
-    aug = augeas.Augeas(flags=augeas.Augeas.NO_LOAD +
+    aug = augeas.Augeas(
-                        augeas.Augeas.NO_MODL_AUTOLOAD)
+        flags=augeas.Augeas.NO_LOAD + augeas.Augeas.NO_MODL_AUTOLOAD)
     aug.set('/augeas/load/Httpd/lens', 'Httpd.lns')
     conf_file = APACHE_HOMEPAGE_CONFIG if os.path.exists(
         APACHE_HOMEPAGE_CONFIG) else FREEDOMBOX_APACHE_CONFIG
@@ -120,9 +120,13 @@ def setup(helper, old_version=None):
 def _migrate_home_page_config():
     """Move the home page configuration to an external file."""
 
-    # Hold the current default app in a variable
+    # Hold the current home page path in a variable
     home_page_path = get_home_page().replace('_', '/')
 
-    # Write the default app setting into the new conf file
+    # Reset the home page to plinth in freedombox.conf
+    actions.superuser_run(
+        'config', ['reset-home-page', '--config', FREEDOMBOX_APACHE_CONFIG])
+
+    # Write the home page setting into the new conf file
     # This step is run at the end because it reloads the Apache server
     actions.superuser_run('config', ['set-home-page', home_page_path])