#!/usr/bin/python
# Copyright (C) 2014-2015  Codethink Limited
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program.  If not, see <http://www.gnu.org/licenses/>.

'''Preparatory checks for Morph 'virtualbox-ssh' write extension'''


import writeexts


class VirtualBoxPlusSshCheckExtension(writeexts.WriteExtension):
    def process_args(self, args):
        if len(args) != 1:
            raise writeexts.ExtensionError(
                'Wrong number of command line args')

        self.require_btrfs_in_deployment_host_kernel()

        upgrade = self.get_environment_boolean('UPGRADE')
        if upgrade:
            raise writeexts.ExtensionError(
                'Use the `ssh-rsync` write extension to deploy upgrades to an '
                'existing remote system.')

VirtualBoxPlusSshCheckExtension().run()