#!/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 fnmatch
import re
import sys
import libvirt

import lib

def cmdline (subparsers):
    p = subparsers.add_parser (
        'migrate',
        help='live migrate virtual machine(s)',
    )
    p.add_argument (
        'wildcards', nargs='+',
        help='virtual machine(s) to be migrated'
    )
    p.add_argument (
        'dest',
        help='destination node'
    )
    p.set_defaults (run=run)

def run (c, args, nodes):
    running, _ = lib.get_all_guests (c, nodes.values ())

    # Identify the VMs to be migrated.
    migrate_vms = []
    for vm in running.values():
        node = vm['node']
        dom = vm['dom']
        # Form the name of this VM (eg. "ham0:vm") so we can match it
        # against the wildcards (eg. "ham0:*")
        name = node.name + ":" + dom.name()
        for wc in args.wildcards:
            if fnmatch.fnmatch (name, wc) or fnmatch.fnmatch (dom.name(), wc):
                migrate_vms.append (vm)

    if not migrate_vms:
        sys.exit ("error: no VMs are going to be migrated")

    # Get destination node.  It can be written either 'dest' or 'dest:'
    m = re.match (r'(.*):$', args.dest)
    if m:
        args.dest = m.group (1)

    if args.dest not in nodes:
        sys.exit ("error: destination node (%s) does not exist" % args.dest)
    dest = nodes[args.dest]

    dconn = libvirt.open (dest.uri)
    if dconn == None:
        sys.exit ("error: could not open a libvirt connection to %s (URI: %s)" %
                  (dest.host, dest.uri))

    for vm in migrate_vms:
        dom = vm['dom']
        dom.migrate (dconn, libvirt.VIR_MIGRATE_LIVE)