core-admin-client/qubesadmin/events/utils.py
Marek Marczykowski-Górecki 5430e04e1c
tools: move event loop creation/closing to main function
Do not close event loop in utility function - handle it only in main().
For this reason, change appropriate functions to coroutines.

Fixes QubesOS/qubes-issues#2865
2017-06-25 20:09:10 +02:00

75 lines
2.4 KiB
Python

# -*- encoding: utf8 -*-
#
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 2017 Marek Marczykowski-Górecki
# <marmarek@invisiblethingslab.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with this program; if not, see <http://www.gnu.org/licenses/>.
''' Utilities for common events-based actions '''
import asyncio
import functools
import qubesadmin.events
import qubesadmin.exc
class Interrupt(Exception):
'''Interrupt events processing'''
def interrupt_on_vm_shutdown(vm, subject, event):
'''Interrupt events processing when given VM was shutdown'''
# pylint: disable=unused-argument
if event == 'connection-established':
if vm.is_halted():
raise Interrupt
elif event == 'domain-shutdown' and vm == subject:
raise Interrupt
@asyncio.coroutine
def wait_for_domain_shutdown(vm, timeout, loop=None):
''' Helper function to wait for domain shutdown.
This function wait for domain shutdown, but do not initiate the shutdown
itself.
:param vm: QubesVM object to wait for shutdown on
:param timeout: Timeout in seconds, use 0 for no timeout
:param loop: asyncio event loop
'''
if loop is None:
loop = asyncio.get_event_loop()
events = qubesadmin.events.EventsDispatcher(vm.app)
events.add_handler('domain-shutdown',
functools.partial(interrupt_on_vm_shutdown, vm))
events.add_handler('connection-established',
functools.partial(interrupt_on_vm_shutdown, vm))
events_task = asyncio.ensure_future(events.listen_for_events(),
loop=loop)
if timeout:
# pylint: disable=no-member
loop.call_later(timeout, events_task.cancel)
try:
yield from events_task
except asyncio.CancelledError:
raise qubesadmin.exc.QubesVMShutdownTimeout(
'VM %s shutdown timeout expired', vm.name)
except Interrupt:
pass