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#!/usr/bin/env python3
# This file is part of cloud-init. See LICENSE file for license information.
"""Handle reconfiguration on hotplug events."""
import abc
import argparse
import os
import sys
import time
from cloudinit import log, reporting, stages
from cloudinit.event import EventScope, EventType
from cloudinit.net import read_sys_net_safe
from cloudinit.net.network_state import parse_net_config_data
from cloudinit.reporting import events
from cloudinit.sources import DataSource, DataSourceNotFoundException
from cloudinit.stages import Init
LOG = log.getLogger(__name__)
NAME = "hotplug-hook"
def get_parser(parser=None):
"""Build or extend an arg parser for hotplug-hook utility.
@param parser: Optional existing ArgumentParser instance representing the
subcommand which will be extended to support the args of this utility.
@returns: ArgumentParser with proper argument configuration.
"""
if not parser:
parser = argparse.ArgumentParser(prog=NAME, description=__doc__)
parser.description = __doc__
parser.add_argument(
"-s",
"--subsystem",
required=True,
help="subsystem to act on",
choices=["net"],
)
subparsers = parser.add_subparsers(
title="Hotplug Action", dest="hotplug_action"
)
subparsers.required = True
subparsers.add_parser(
"query", help="Query if hotplug is enabled for given subsystem."
)
parser_handle = subparsers.add_parser(
"handle", help="Handle the hotplug event."
)
parser_handle.add_argument(
"-d",
"--devpath",
required=True,
metavar="PATH",
help="Sysfs path to hotplugged device",
)
parser_handle.add_argument(
"-u",
"--udevaction",
required=True,
help="Specify action to take.",
choices=["add", "remove"],
)
return parser
class UeventHandler(abc.ABC):
def __init__(self, id, datasource, devpath, action, success_fn):
self.id = id
self.datasource: DataSource = datasource
self.devpath = devpath
self.action = action
self.success_fn = success_fn
@abc.abstractmethod
def apply(self):
raise NotImplementedError()
@property
@abc.abstractmethod
def config(self):
raise NotImplementedError()
@abc.abstractmethod
def device_detected(self) -> bool:
raise NotImplementedError()
def detect_hotplugged_device(self):
detect_presence = None
if self.action == "add":
detect_presence = True
elif self.action == "remove":
detect_presence = False
else:
raise ValueError("Unknown action: %s" % self.action)
if detect_presence != self.device_detected():
raise RuntimeError(
"Failed to detect %s in updated metadata" % self.id
)
def success(self):
return self.success_fn()
def update_metadata(self):
result = self.datasource.update_metadata_if_supported(
[EventType.HOTPLUG]
)
if not result:
raise RuntimeError(
"Datasource %s not updated for event %s"
% (self.datasource, EventType.HOTPLUG)
)
return result
class NetHandler(UeventHandler):
def __init__(self, datasource, devpath, action, success_fn):
# convert devpath to mac address
id = read_sys_net_safe(os.path.basename(devpath), "address")
super().__init__(id, datasource, devpath, action, success_fn)
def apply(self):
self.datasource.distro.apply_network_config(
self.config,
bring_up=False,
)
interface_name = os.path.basename(self.devpath)
activator = self.datasource.distro.network_activator()
if self.action == "add":
if not activator.bring_up_interface(interface_name):
raise RuntimeError(
"Failed to bring up device: {}".format(self.devpath)
)
elif self.action == "remove":
if not activator.bring_down_interface(interface_name):
raise RuntimeError(
"Failed to bring down device: {}".format(self.devpath)
)
@property
def config(self):
return self.datasource.network_config
def device_detected(self) -> bool:
netstate = parse_net_config_data(self.config)
found = [
iface
for iface in netstate.iter_interfaces()
if iface.get("mac_address") == self.id
]
LOG.debug("Ifaces with ID=%s : %s", self.id, found)
return len(found) > 0
SUBSYSTEM_PROPERTES_MAP = {
"net": (NetHandler, EventScope.NETWORK),
}
def is_enabled(hotplug_init, subsystem):
try:
scope = SUBSYSTEM_PROPERTES_MAP[subsystem][1]
except KeyError as e:
raise Exception(
"hotplug-hook: cannot handle events for subsystem: {}".format(
subsystem
)
) from e
return stages.update_event_enabled(
datasource=hotplug_init.datasource,
cfg=hotplug_init.cfg,
event_source_type=EventType.HOTPLUG,
scope=scope,
)
def initialize_datasource(hotplug_init: Init, subsystem: str):
LOG.debug("Fetching datasource")
datasource = hotplug_init.fetch(existing="trust")
if not datasource.get_supported_events([EventType.HOTPLUG]):
LOG.debug("hotplug not supported for event of type %s", subsystem)
return
if not is_enabled(hotplug_init, subsystem):
LOG.debug("hotplug not enabled for event of type %s", subsystem)
return
return datasource
def handle_hotplug(hotplug_init: Init, devpath, subsystem, udevaction):
datasource = initialize_datasource(hotplug_init, subsystem)
if not datasource:
return
handler_cls = SUBSYSTEM_PROPERTES_MAP[subsystem][0]
LOG.debug("Creating %s event handler", subsystem)
event_handler: UeventHandler = handler_cls(
datasource=datasource,
devpath=devpath,
action=udevaction,
success_fn=hotplug_init._write_to_cache,
)
wait_times = [1, 3, 5, 10, 30]
last_exception = Exception("Bug while processing hotplug event.")
for attempt, wait in enumerate(wait_times):
LOG.debug(
"subsystem=%s update attempt %s/%s",
subsystem,
attempt,
len(wait_times),
)
try:
LOG.debug("Refreshing metadata")
event_handler.update_metadata()
if not datasource.skip_hotplug_detect:
LOG.debug("Detecting device in updated metadata")
event_handler.detect_hotplugged_device()
LOG.debug("Applying config change")
event_handler.apply()
LOG.debug("Updating cache")
event_handler.success()
break
except Exception as e:
LOG.debug("Exception while processing hotplug event. %s", e)
time.sleep(wait)
last_exception = e
else:
raise last_exception
def handle_args(name, args):
# Note that if an exception happens between now and when logging is
# setup, we'll only see it in the journal
hotplug_reporter = events.ReportEventStack(
name, __doc__, reporting_enabled=True
)
hotplug_init = Init(ds_deps=[], reporter=hotplug_reporter)
hotplug_init.read_cfg()
log.setupLogging(hotplug_init.cfg)
if "reporting" in hotplug_init.cfg:
reporting.update_configuration(hotplug_init.cfg.get("reporting"))
# Logging isn't going to be setup until now
LOG.debug(
"%s called with the following arguments: {"
"hotplug_action: %s, subsystem: %s, udevaction: %s, devpath: %s}",
name,
args.hotplug_action,
args.subsystem,
args.udevaction if "udevaction" in args else None,
args.devpath if "devpath" in args else None,
)
with hotplug_reporter:
try:
if args.hotplug_action == "query":
try:
datasource = initialize_datasource(
hotplug_init, args.subsystem
)
except DataSourceNotFoundException:
print(
"Unable to determine hotplug state. No datasource "
"detected"
)
sys.exit(1)
print("enabled" if datasource else "disabled")
else:
handle_hotplug(
hotplug_init=hotplug_init,
devpath=args.devpath,
subsystem=args.subsystem,
udevaction=args.udevaction,
)
except Exception:
LOG.exception("Received fatal exception handling hotplug!")
raise
LOG.debug("Exiting hotplug handler")
reporting.flush_events()
if __name__ == "__main__":
args = get_parser().parse_args()
handle_args(NAME, args)
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