#!/usr/bin/python
# Copyright (C) 2012-2014  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 KVM+libvirt.'''


import cliapp
import os
import re
import sys
import tempfile
import urlparse

import morphlib.writeexts


class KvmPlusSshWriteExtension(morphlib.writeexts.WriteExtension):

    '''Create a KVM/LibVirt virtual machine during Morph's deployment.
    
    The location command line argument is the pathname of the disk image
    to be created. The user is expected to provide the location argument
    using the following syntax:
    
        kvm+ssh://HOST/GUEST/PATH
        
    where:
    
    * HOST is the host on which KVM/LibVirt is running
    * GUEST is the name of the guest virtual machine on that host
    * PATH is the path to the disk image that should be created,
      on that host
  
    The extension will connect to HOST via ssh to run libvirt's
    command line management tools.
    
    '''

    location_pattern = '^/(?P<guest>[^/]+)(?P<path>/.+)$'

    def process_args(self, args):
        if len(args) != 2:
            raise cliapp.AppException('Wrong number of command line args')
        
        temp_root, location = args
        ssh_host, vm_name, vm_path = self.parse_location(location)
        autostart = self.get_environment_boolean('AUTOSTART')
        
        fd, raw_disk = tempfile.mkstemp()
        os.close(fd)
        self.create_local_system(temp_root, raw_disk)
        
        try:
            self.transfer(raw_disk, ssh_host, vm_path)
            self.create_libvirt_guest(ssh_host, vm_name, vm_path, autostart)
        except BaseException:
            sys.stderr.write('Error deploying to libvirt')
            os.remove(raw_disk)
            cliapp.ssh_runcmd(ssh_host, ['rm', '-f', vm_path])
            raise
        else:
            os.remove(raw_disk)

        self.status(
            msg='Virtual machine %(vm_name)s has been created',
            vm_name=vm_name)

    def parse_location(self, location):
        '''Parse the location argument to get relevant data.'''

        x = urlparse.urlparse(location)
        m = re.match('^/(?P<guest>[^/]+)(?P<path>/.+)$', x.path)
        return x.netloc, m.group('guest'), m.group('path')

    def transfer(self, raw_disk, ssh_host, vm_path):
        '''Transfer raw disk image to libvirt host.'''

        self.status(msg='Transferring disk image to %s on %s' %
                    (vm_path, ssh_host))
        target = '%s:%s' % (ssh_host, vm_path)
        with open(raw_disk, 'rb') as f:
            cliapp.runcmd(['rsync', '-szS', raw_disk, target])

    def create_libvirt_guest(self, ssh_host, vm_name, vm_path, autostart):
        '''Create the libvirt virtual machine.'''
        
        self.status(msg='Creating libvirt/kvm virtual machine')

        attach_disks = self.parse_attach_disks()
        attach_opts = []
        for disk in attach_disks:
            attach_opts.extend(['--disk', 'path=%s' % disk])

        if 'NIC_CONFIG' in os.environ:
            nics = os.environ['NIC_CONFIG'].split()
            for nic in nics:
                attach_opts.extend(['--network', nic])

        ram_mebibytes = str(self.get_ram_size() / (1024**2))

        vcpu_count = str(self.get_vcpu_count())

        cmdline = ['virt-install', '--connect', 'qemu:///system',
                   '--import', '--name', vm_name, '--vnc',
                   '--ram', ram_mebibytes, '--vcpus', vcpu_count,
                   '--disk', 'path=%s,bus=ide' % vm_path] + attach_opts
        if not autostart:
            cmdline += ['--noreboot']
        cliapp.ssh_runcmd(ssh_host, cmdline)

        if autostart:
            cliapp.ssh_runcmd(ssh_host,
                ['virsh', '--connect', 'qemu:///system', 'autostart', vm_name])

KvmPlusSshWriteExtension().run()