radicale: Handle migration from 1.x to 2.x

When radicale 2.x is available in testing, the migration can be
triggered by bumping the module's version.

Signed-off-by: James Valleroy <jvalleroy@mailbox.org>
Reviewed-by: Sunil Mohan Adapa <sunil@medhas.org>

actions/radicale

@@ -38,6 +38,7 @@ def parse_arguments():
     subparsers = parser.add_subparsers(dest='subcommand', help='Sub command')
 
     subparsers.add_parser('setup', help='Setup Radicale configuration')
+    subparsers.add_parser('migrate', help='Migrate config to radicale 2.x')
     subparsers.add_parser('enable', help='Enable Radicale service')
     subparsers.add_parser('disable', help='Disable Radicale service')
     configure = subparsers.add_parser('configure',
@@ -74,6 +75,26 @@ def subcommand_setup(_):
     subcommand_enable(None)
 
 
+def subcommand_migrate(_):
+    """Migrate config from radicale 1.x to 2.x."""
+    action_utils.webserver_disable('radicale-plinth')
+
+    aug = load_augeas()
+
+    # Revert the config to package's original.
+    aug.remove('/files' + DEFAULT_FILE + '/ENABLE_RADICALE')
+    aug.remove('/files' + CONFIG_FILE + '/server/hosts')
+    aug.remove('/files' + CONFIG_FILE + '/server/base_prefix')
+    aug.remove('/files' + CONFIG_FILE + '/well-known/caldav')
+    aug.remove('/files' + CONFIG_FILE + '/well-known/carddav')
+    aug.remove('/files' + CONFIG_FILE + '/auth/type')
+    current_version = radicale.get_package_version()
+    if current_version and current_version < radicale.VERSION_2:
+        aug.remove('/files' + CONFIG_FILE + '/rights/type')
+
+    aug.save()
+
+
 def subcommand_configure(arguments):
     """Sets the radicale rights type to a particular value"""
     current_version = radicale.get_package_version()
@@ -122,8 +143,8 @@ def subcommand_disable(_):
 
 def load_augeas():
     """Initialize Augeas."""
-    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)
 
     # shell-script config file lens
     aug.set('/augeas/load/Shellvars/lens', 'Shellvars.lns')

plinth/modules/radicale/__init__.py

@@ -21,6 +21,7 @@ FreedomBox app for radicale.
 import subprocess
 from distutils.version import LooseVersion as LV
 
+from apt.cache import Cache
 import augeas
 from django.urls import reverse_lazy
 from django.utils.translation import ugettext_lazy as _
@@ -84,8 +85,31 @@ def init():
 
 def setup(helper, old_version=None):
     """Install and configure the module."""
-    helper.install(managed_packages)
+    if old_version == 1:
-    helper.call('post', actions.superuser_run, 'radicale', ['setup'])
+        # Check that radicale 2.x is available for install.
+        cache = Cache()
+        candidate = cache['radicale'].candidate
+        if candidate < '2':
+            raise RuntimeError('Radicale 2.x is not available to install.')
+
+        # Try to upgrade radicale 1.x to 2.x.
+        helper.call('pre', actions.superuser_run, 'radicale', ['migrate'])
+        helper.install(managed_packages)
+
+        # Check that radicale 2.x is installed.
+        current_version = get_package_version()
+        if not current_version:
+            raise RuntimeError(
+                'Could not determine installed version of radicale.')
+        elif current_version < VERSION_2:
+            raise RuntimeError('Could not install radicale 2.x.')
+
+        # Enable radicale.
+        helper.call('post', actions.superuser_run, 'radicale', ['setup'])
+    else:
+        helper.install(managed_packages)
+        helper.call('post', actions.superuser_run, 'radicale', ['setup'])
+
     global service
     if service is None:
         service = service_module.Service(managed_services[0], name, ports=[
@@ -162,8 +186,8 @@ def disable():
 
 def load_augeas():
     """Prepares the augeas."""
-    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)
 
     # INI file lens
     aug.set('/augeas/load/Puppet/lens', 'Puppet.lns')