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#!/usr/bin/python
# Copyright 2016 Google Inc. All Rights Reserved.
#
# 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.
"""Enables the network interfaces provided in metadata."""
import fileinput
import logging.handlers
import optparse
import os
import re
import subprocess
from google_compute_engine import config_manager
from google_compute_engine import logger
from google_compute_engine import metadata_watcher
from google_compute_engine import network_utils
class NetworkSetup(object):
"""Enable network interfaces specified by metadata."""
network_interfaces = 'instance/network-interfaces'
def __init__(self, dhclient_script=None, dhcp_command=None, debug=False):
"""Constructor.
Args:
dhclient_script: string, the path to a dhclient script used by dhclient.
dhcp_command: string, a command to enable Ethernet interfaces.
debug: bool, True if debug output should write to the console.
"""
self.dhclient_script = dhclient_script or '/sbin/google-dhclient-script'
self.dhcp_command = dhcp_command
facility = logging.handlers.SysLogHandler.LOG_DAEMON
self.logger = logger.Logger(
name='network-setup', debug=debug, facility=facility)
self.watcher = metadata_watcher.MetadataWatcher(logger=self.logger)
self.network_utils = network_utils.NetworkUtils(logger=self.logger)
self._SetupNetworkInterfaces()
def _ModifyInterface(
self, interface_config, config_key, config_value, replace=False):
"""Write a value to a config file if not already present.
Args:
interface_config: string, the path to a config file.
config_key: string, the configuration key to set.
config_value: string, the value to set for the configuration key.
replace: bool, replace the configuration option if already present.
"""
config_entry = '%s=%s' % (config_key, config_value)
if not open(interface_config).read().count(config_key):
with open(interface_config, 'a') as config:
config.write('%s\n' % config_entry)
elif replace:
for line in fileinput.input(interface_config, inplace=True):
print(re.sub(r'%s=.*' % config_key, config_entry, line.rstrip()))
def _DisableNetworkManager(self, interfaces):
"""Disable network manager management on a list of network interfaces.
Args:
interfaces: list of string, the output device names enable.
"""
interface_path = '/etc/sysconfig/network-scripts'
for interface in interfaces:
interface_config = os.path.join(interface_path, 'ifcfg-%s' % interface)
if os.path.exists(interface_config):
self._ModifyInterface(
interface_config, 'DEVICE', interface, replace=False)
self._ModifyInterface(
interface_config, 'NM_CONTROLLED', 'no', replace=True)
else:
with open(interface_config, 'w') as interface_file:
interface_content = [
'# Added by Google.',
'BOOTPROTO=none',
'DEFROUTE=no',
'DEVICE=%s' % interface,
'IPV6INIT=no',
'NM_CONTROLLED=no',
'NOZEROCONF=yes',
'',
]
interface_file.write('\n'.join(interface_content))
self.logger.info('Created config file for interface %s.', interface)
def _ConfigureNetwork(self, interfaces):
"""Enable the list of network interfaces.
Args:
interfaces: list of string, the output device names enable.
"""
self.logger.info('Enabling the Ethernet interfaces %s.', interfaces)
dhclient_command = ['dhclient']
if os.path.exists(self.dhclient_script):
dhclient_command += ['-sf', self.dhclient_script]
try:
subprocess.check_call(dhclient_command + ['-x'] + interfaces)
subprocess.check_call(dhclient_command + interfaces)
except subprocess.CalledProcessError:
self.logger.warning('Could not enable interfaces %s.', interfaces)
def _EnableNetworkInterfaces(self, interfaces):
"""Enable the list of network interfaces.
Args:
interfaces: list of string, the output device names to enable.
"""
# The default Ethernet interface is enabled by default. Do not attempt to
# enable interfaces if only one interface is specified in metadata.
if not interfaces or len(interfaces) <= 1:
return
if self.dhcp_command:
try:
subprocess.check_call([self.dhcp_command])
except subprocess.CalledProcessError:
self.logger.warning('Could not enable Ethernet interfaces.')
else:
if os.path.exists('/etc/sysconfig/network-scripts'):
self._DisableNetworkManager(interfaces)
self._ConfigureNetwork(interfaces)
def _SetupNetworkInterfaces(self):
"""Get network interfaces metadata and enable each Ethernet interface."""
result = self.watcher.GetMetadata(
metadata_key=self.network_interfaces, recursive=True)
interfaces = []
for network_interface in result:
mac_address = network_interface.get('mac')
interface = self.network_utils.GetNetworkInterface(mac_address)
if interface:
interfaces.append(interface)
else:
message = 'Network interface not found for MAC address: %s.'
self.logger.warning(message, mac_address)
self._EnableNetworkInterfaces(interfaces)
def main():
parser = optparse.OptionParser()
parser.add_option(
'-d', '--debug', action='store_true', dest='debug',
help='print debug output to the console.')
(options, _) = parser.parse_args()
instance_config = config_manager.ConfigManager()
if instance_config.GetOptionBool('NetworkInterfaces', 'setup'):
NetworkSetup(
dhclient_script=instance_config.GetOptionString(
'NetworkInterfaces', 'dhclient_script'),
dhcp_command=instance_config.GetOptionString(
'NetworkInterfaces', 'dhcp_command'),
debug=bool(options.debug))
if __name__ == '__main__':
main()
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