135 lines
4.1 KiB
Python
135 lines
4.1 KiB
Python
#!/usr/bin/env python
|
|
|
|
# Licensed 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 "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
|
|
"""
|
|
Command-line utility to get the IP address from the newest DHCP lease.
|
|
|
|
It's written for using with vagrant-hostmanager and vagrant-libvirt plugins.
|
|
Vagrant-hostmanager by default fetches only IP addresses from eth0 interfaces
|
|
on VM-s. Therefore, the first purpose of this utility is to be able to fetch
|
|
the address also from the other interfaces.
|
|
|
|
Libvirt/virsh only lists all DHCP leases for the given network with timestamps.
|
|
DHCP leases have their expiration time, but are not cleaned up after destroying
|
|
VM. If someone destroys and sets up the VM with the same hostname, we have
|
|
many DHCP leases for the same hostname and we have to look up for timestamp.
|
|
That's the second purpose of this script.
|
|
"""
|
|
|
|
import argparse
|
|
import csv
|
|
import functools
|
|
import operator
|
|
import xml.etree.ElementTree as etree
|
|
|
|
import libvirt
|
|
|
|
|
|
class NoPrivateDHCPInterfaceException(Exception):
|
|
pass
|
|
|
|
|
|
class NoDHCPLeaseException(Exception):
|
|
pass
|
|
|
|
|
|
def libvirt_conn(f):
|
|
@functools.wraps(f)
|
|
def wrapper(*args, **kwargs):
|
|
conn = libvirt.openReadOnly('qemu:///system')
|
|
return f(conn, *args, **kwargs)
|
|
return wrapper
|
|
|
|
|
|
@libvirt_conn
|
|
def get_vir_network_dhcp_lease(conn, vm_name):
|
|
"""Libvirt since 1.2.6 version provides DHCPLeases method in virNetwork.
|
|
|
|
That's the current official way for getting DHCP leases and this
|
|
information isn't stored anywhere else anymore.
|
|
"""
|
|
domain_name = 'vagrant_' + vm_name
|
|
mac_address = get_mac_address(conn, domain_name)
|
|
|
|
network = conn.networkLookupByName('vagrant-private-dhcp')
|
|
dhcp_leases = libvirt.virNetwork.DHCPLeases(network)
|
|
|
|
vm_dhcp_leases = [lease for lease in dhcp_leases
|
|
if lease['mac'] == mac_address]
|
|
|
|
newest_vm_dhcp_lease = sorted(vm_dhcp_leases,
|
|
key=operator.itemgetter('expirytime'),
|
|
reverse=True)[0]['ipaddr']
|
|
return newest_vm_dhcp_lease
|
|
|
|
|
|
def get_mac_address(conn, domain_name):
|
|
"""Get MAC address from domain XML."""
|
|
domain = conn.lookupByName(domain_name)
|
|
domain_xml = domain.XMLDesc()
|
|
domain_tree = etree.fromstring(domain_xml)
|
|
devices = domain_tree.find('devices')
|
|
interfaces = devices.iterfind('interface')
|
|
|
|
for interface in interfaces:
|
|
source = interface.find('source')
|
|
if source is None or source.get('network') != 'vagrant-private-dhcp':
|
|
continue
|
|
mac_element = interface.find('mac')
|
|
mac_address = mac_element.get('address')
|
|
return mac_address
|
|
|
|
raise NoPrivateDHCPInterfaceException()
|
|
|
|
|
|
@libvirt_conn
|
|
def get_dnsmasq_dhcp_lease(conn, vm_name):
|
|
"""In libvirt under 1.2.6 DHCP leases are stored in file.
|
|
|
|
There is no API for DHCP leases yet.
|
|
"""
|
|
domain_name = 'vagrant_' + vm_name
|
|
mac_address = get_mac_address(conn, domain_name)
|
|
|
|
with open(
|
|
'/var/lib/libvirt/dnsmasq/vagrant-private-dhcp.leases'
|
|
) as leases_file:
|
|
reader = csv.reader(leases_file, delimiter=' ')
|
|
for row in reader:
|
|
lease_mac, lease_ip, lease_vm_name = row[1:4]
|
|
if not (lease_mac == mac_address and lease_vm_name == vm_name):
|
|
continue
|
|
return lease_ip
|
|
|
|
raise NoDHCPLeaseException()
|
|
|
|
|
|
def main():
|
|
parser = argparse.ArgumentParser()
|
|
parser.add_argument('vm_name', help='Name of the virtual machine')
|
|
|
|
args = parser.parse_args()
|
|
vm_name = args.vm_name
|
|
|
|
if libvirt.getVersion() >= 1002006:
|
|
newest_dhcp_lease = get_vir_network_dhcp_lease(vm_name)
|
|
else:
|
|
newest_dhcp_lease = get_dnsmasq_dhcp_lease(vm_name)
|
|
|
|
print(newest_dhcp_lease)
|
|
|
|
|
|
if __name__ == '__main__':
|
|
main()
|