#!/usr/bin/python
# mclu (mini cluster)
# Copyright (C) 2014 Red Hat Inc.
#
# 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; either version 2 of the License, or
# (at your option) any later version.
#
# 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.

import argparse
import os
import re
import subprocess
import sys
import libvirt

import config
import lib
import libvirt_xml

def cmdline (subparsers):
    p = subparsers.add_parser (
        'build',
        help='build and run a new virtual machine',
    )
    p.add_argument (
        '--memory', default=1024, type=int,
        help='RAM to give to guest (default unit is megabytes)'
    )
    p.add_argument (
        '--vcpus', default=4, type=int,
        help='virtual CPUs to give to guest'
    )
    p.add_argument (
        '--virtio', default=True,
        help='use virtio disks and network'
    )
    p.add_argument (
        '--size', required=True,
        help='size of disk'
    )
    p.add_argument (
        'name',
        help='name of the new VM (or use "vm:name")'
    )
    p.add_argument (
        'os_version',
        help='OS & version of guest (see virt-builder docs)'
    )
    p.add_argument (
        'vbargs', nargs='*',
        help='virt-builder arguments (after "--")'
    )
    p.set_defaults (run=run)

def run (c, args):
    # Did the user request a particular node?  If not, we'll run it
    # on any node which is up.
    m = re.match (r'^(.*):(.*)$', args.name)
    if m:
        node_name = m.group (1)
        vm_name = m.group (2)
    else:
        node = lib.pick_any_node_which_is_up (c)
        vm_name = args.name

    # Get all the guests, so we can tell if the name is a duplicate.
    running, inactive = lib.get_all_guests (c)

    if vm_name in running or vm_name in inactive:
        sys.exit ("error: node name (%s) already exists" % vm_name)

    output = '%s/%s.img' % (c['images_dir'], vm_name)

    # Call out to virt-builder to build the disk image.
    vbargs = [
        config.VIRT_BUILDER,
        args.os_version,
        '--output', output,
        '--format', 'qcow2',
    ]
    if args.size:
        vbargs.extend (['--size', args.size])
    if args.vbargs:
        vbargs.extend (args.vbargs)
    subprocess.check_call (vbargs)

    # XXX Unfortunately this is necessary so qemu can access the disk.
    os.chmod (output, 0666)

    # Generate the XML.  Would be nice to use virt-install here, but
    # it doesn't work: RHBZ#1095789
    xml = libvirt_xml.generate_libvirt_xml (vm_name,
                                            args.memory,
                                            args.vcpus,
                                            args.virtio,
                                            output)

    # Write the XML to the xmls_dir.
    fp = open ("%s/%s.xml" % (c['xmls_dir'], vm_name), "w")
    fp.write (xml)
    fp.close ()

    # Start the guest.
    lib.start_guest (c, node_name, vm_name)
    print "guest built and started on node %s" % node_name