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# This file is part of cloud-init. See LICENSE file for license information.
"""Run the dhclient hook to record network info."""
import argparse
import os
from cloudinit import atomic_helper
from cloudinit import log as logging
from cloudinit import stages
LOG = logging.getLogger(__name__)
NAME = "dhclient-hook"
UP = "up"
DOWN = "down"
EVENTS = (UP, DOWN)
def _get_hooks_dir():
i = stages.Init()
return os.path.join(i.paths.get_runpath(), "dhclient.hooks")
def _filter_env_vals(info):
"""Given info (os.environ), return a dictionary with
lower case keys for each entry starting with DHCP4_ or new_."""
new_info = {}
for k, v in info.items():
if k.startswith("DHCP4_") or k.startswith("new_"):
key = (k.replace("DHCP4_", "").replace("new_", "")).lower()
new_info[key] = v
return new_info
def run_hook(interface, event, data_d=None, env=None):
if event not in EVENTS:
raise ValueError(
"Unexpected event '%s'. Expected one of: %s" % (event, EVENTS)
)
if data_d is None:
data_d = _get_hooks_dir()
if env is None:
env = os.environ
hook_file = os.path.join(data_d, interface + ".json")
if event == UP:
if not os.path.exists(data_d):
os.makedirs(data_d)
atomic_helper.write_json(hook_file, _filter_env_vals(env))
LOG.debug("Wrote dhclient options in %s", hook_file)
elif event == DOWN:
if os.path.exists(hook_file):
os.remove(hook_file)
LOG.debug("Removed dhclient options file %s", hook_file)
def get_parser(parser=None):
if parser is None:
parser = argparse.ArgumentParser(prog=NAME, description=__doc__)
parser.add_argument(
"event", help="event taken on the interface", choices=EVENTS
)
parser.add_argument(
"interface", help="the network interface being acted upon"
)
# cloud-init main uses 'action'
parser.set_defaults(action=(NAME, handle_args))
return parser
def handle_args(name, args, data_d=None):
"""Handle the Namespace args.
Takes 'name' as passed by cloud-init main. not used here."""
return run_hook(interface=args.interface, event=args.event, data_d=data_d)
if __name__ == "__main__":
import sys
parser = get_parser()
args = parser.parse_args(args=sys.argv[1:])
return_value = handle_args(
NAME, args, data_d=os.environ.get("_CI_DHCP_HOOK_DATA_D")
)
if return_value:
sys.exit(return_value)
# vi: ts=4 expandtab
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