Merge "Fetching IP addresses for vagrant-hostmanager from libvirt"

dev/vagrant/Vagrantfile

@@ -141,7 +141,7 @@ Vagrant.configure(2) do |config|
     case PROVIDER
     when "libvirt"
       if vm.name
-        `virsh -c qemu:///system net-dhcp-leases vagrant-private-dhcp | awk -F'[ /]+' '/#{vm.name} / {print $6}'`.chop
+        `python newest_dhcp_lease.py #{vm.name}`.chop
       end
     when "virtualbox_ubuntu"
     when "virtualbox_centos"

dev/vagrant/newest_dhcp_lease.py

@@ -0,0 +1,131 @@
+#!/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 NoBridgeInterfaceException(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.
+    """
+    network = conn.networkLookupByName('vagrant-private-dhcp')
+    dhcp_leases = libvirt.virNetwork.DHCPLeases(network)
+
+    vm_dhcp_leases = filter(lambda lease: lease['hostname'] == vm_name,
+                            dhcp_leases)
+
+    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:
+        interface_type = interface.get('type')
+        if interface_type != 'bridge':
+            continue
+        mac_element = interface.find('mac')
+        mac_address = mac_element.get('address')
+        return mac_address
+
+    raise NoBridgeInterfaceException()
+
+
+@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()