#!/usr/bin/python
# Copyright (C) 2013  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, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.


'''A Morph deployment write extension for deploying to OpenStack.'''


import cliapp
import os
import tempfile
import urlparse

import morphlib.writeexts


class OpenStackWriteExtension(morphlib.writeexts.WriteExtension):

    '''Configure a raw disk image into an OpenStack host.

    The raw disk image is created during Morph's deployment and the
    image is deployed in OpenStack using python-glanceclient.
    
    The location command line argument is the authentification url
    of the OpenStack server using the following syntax:
 
    http://HOST:PORT/VERSION

    where

    * HOST is the host running OpenStack
    * PORT is the port which is using OpenStack for authentifications.
    * VERSION is the authentification version of OpenStack (Only v2.0
      supported)

    This extension needs in the environment the following variables:
 
    * OPENSTACK_USER is the username to use in the deployment.
    * OPENSTACK_TENANT is the project name to use in the deployment.
    * OPENSTACK_IMAGENAME is the name of the image to create.
    * OPENSTACK_PASSWORD is the password of the user.
        

    The extension will connect to OpenStack using python-glanceclient
    to configure a raw image.
    
    '''

    def process_args(self, args):
        if len(args) != 2:
            raise cliapp.AppException('Wrong number of command line args')
        
        temp_root, location = args
        self.check_location(location)

        os_params = self.get_openstack_parameters()

        fd, raw_disk = tempfile.mkstemp()
        os.close(fd)
        self.create_local_system(temp_root, raw_disk)
        self.status(msg='Temporary disk image has been created at %s' 
                    % raw_disk)

        self.set_extlinux_root_to_virtio(raw_disk)

        self.configure_openstack_image(raw_disk, location, os_params)

    def set_extlinux_root_to_virtio(self, raw_disk):
        '''Re-configures extlinux to use virtio disks'''
        self.status(msg='Updating extlinux.conf')
        mp = self.mount(raw_disk)
        try:
            path = os.path.join(mp, 'extlinux.conf')

            with open(path) as f:
                extlinux_conf = f.read()

            extlinux_conf = extlinux_conf.replace('root=/dev/sda',
                                                  'root=/dev/vda')
            with open(path, "w") as f:
                f.write(extlinux_conf)

        finally:
            self.unmount(mp)

    def get_openstack_parameters(self):
        '''Check the environment variables needed and returns all.

        The environment variables are described in the class documentation.
        '''

        keys = ('OPENSTACK_USER', 'OPENSTACK_TENANT',
                'OPENSTACK_IMAGENAME', 'OPENSTACK_PASSWORD')
        for key in keys:
            if key not in os.environ:
                raise cliapp.AppException(key + ' was not given')
        return (os.environ[key] for key in keys)

    def check_location(self, location):
        x = urlparse.urlparse(location)
        if x.scheme != 'http':
            raise cliapp.AppException('URL schema must be http in %s' \
                                      % location)
        if (x.path != '/v2.0' and x.path != '/v2.0/'):
            raise cliapp.AppException('API version must be v2.0 in %s'\
                                      % location)

    def configure_openstack_image(self, raw_disk, auth_url, os_params):
        '''Configure the image in OpenStack using glance-client'''
        self.status(msg='Configuring OpenStack image...')

        username, tenant_name, image_name, password = os_params
        cmdline = ['glance',
                   '--os-username', username,
                   '--os-tenant-name', tenant_name,
                   '--os-password', password,
                   '--os-auth-url', auth_url,
                   'image-create',
                   '--name=%s' % image_name,
                   '--disk-format=raw',
                   '--container-format', 'bare',
                   '--file', raw_disk]
        cliapp.runcmd(cmdline)

        self.status(msg='Image configured.')

OpenStackWriteExtension().run()