#!/usr/bin/python
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# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
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# specific language governing permissions and limitations
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import logging
import re
import sys
from xml.dom.minidom import parse
from cloudutils.configFileOps import configFileOps
from cloudutils.networkConfig import networkConfig

logging.basicConfig(filename='/var/log/libvirt/qemu-hook.log',
                    filemode='a',
                    format='%(asctime)s,%(msecs)d %(name)s %(levelname)s %(message)s',
                    datefmt='%H:%M:%S',
                    level=logging.INFO)
logger = logging.getLogger('qemu-hook')

def isOldStyleBridge(brName):
    if brName.find("cloudVirBr") == 0:
       return True
    else:
       return False

def isNewStyleBridge(brName):
    if brName.startswith('brvx-'):
        return False
    if re.match(r"br(\w+)-(\d+)", brName) == None:
       return False
    else:
       return True

def getGuestNetworkDevice():
    netlib = networkConfig()
    cfo = configFileOps("/etc/cloudstack/agent/agent.properties")
    guestDev = cfo.getEntry("guest.network.device")
    enslavedDev = netlib.getEnslavedDev(guestDev, 1)
    return enslavedDev.split(".")[0]

def handleMigrateBegin():
    try:
        domain = parse(sys.stdin)
        for interface in domain.getElementsByTagName("interface"):
            source = interface.getElementsByTagName("source")[0]
            bridge = source.getAttribute("bridge")
            if isOldStyleBridge(bridge):
                vlanId = bridge.replace("cloudVirBr", "")
            elif isNewStyleBridge(bridge):
                vlanId = re.sub(r"br(\w+)-", "", bridge)
            else:
                continue
            phyDev = getGuestNetworkDevice()
            newBrName = "br" + phyDev + "-" + vlanId
            source.setAttribute("bridge", newBrName)
        print(domain.toxml())
    except:
        pass


if __name__ == '__main__':
    if len(sys.argv) != 5:
        sys.exit(0)

    # For docs refer https://libvirt.org/hooks.html#qemu
    logger.debug("Executing qemu hook with args: %s" % sys.argv)
    action, status = sys.argv[2:4]

    if action == "migrate" and status == "begin":
        handleMigrateBegin()