# 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)

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