Add QEMU QMP wrapper.

parent cae42bda
......@@ -70,6 +70,7 @@ setup(name=name,
'onetimeupload = slapos.onetimeupload:main',
'pubsubnotifier = slapos.pubsub.notifier:main',
'pubsubserver = slapos.pubsub:main',
'qemu-qmp-client = slapos.qemuqmpclient:main',
'shacache = slapos.shacache:main',
'slapbuilder = slapos.builder:main',
'slapcontainer = slapos.container:main',
......
##############################################################################
#
# Copyright (c) 2013 Vifib SARL and Contributors. All Rights Reserved.
#
# WARNING: This program as such is intended to be used by professional
# programmers who take the whole responsibility of assessing all potential
# consequences resulting from its eventual inadequacies and bugs
# End users who are looking for a ready-to-use solution with commercial
# guarantees and support are strongly adviced to contract a Free Software
# Service Company
#
# This program is Free Software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 3
# 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#
##############################################################################
import argparse
import json
import os
import socket
import time
QMP_STOP_ACTION = 'suspend'
QMP_RESUME_ACTION = 'resume'
QMP_CAPABILITIES_ACTION = 'capabilities'
def parseArgument():
"""
Very basic argument parser. Might blow up for anything else than
"./executable mysocket.sock stop/resume".
"""
parser = argparse.ArgumentParser()
parser.add_argument('unix_socket_location')
parser.add_argument(
'action',
choices=[QMP_STOP_ACTION, QMP_RESUME_ACTION, QMP_CAPABILITIES_ACTION]
)
args = parser.parse_args()
return args.unix_socket_location, args.action
class QemuQMPWrapper(object):
"""
Small wrapper around Qemu's QMP to control a qemu VM.
See http://git.qemu.org/?p=qemu.git;a=blob;f=qmp-commands.hx for
QMP API definition.
"""
def __init__(self, unix_socket_location):
self.socket = self.connectToQemu(unix_socket_location)
self.capabilities()
@staticmethod
def connectToQemu(unix_socket_location):
"""
Create a socket, connect to qemu, be sure it answers, return socket.
"""
if not os.path.exists(unix_socket_location):
raise Exception('unix socket %s does not exist.' % unix_socket_location)
print 'Connecting to qemu...'
so = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
connected = False
while not connected:
try:
so.connect(unix_socket_location)
except socket.error:
time.sleep(1)
print 'Could not connect, retrying...'
else:
connected = True
so.recv(1024)
return so
def _send(self, message):
self.socket.send(json.dumps(message))
data = self.socket.recv(1024)
try:
return json.loads(data)
except ValueError:
print 'Wrong data: %s' % data
def _getVMStatus(self):
response = self._send({'execute': 'query-status'})
if response:
return self._send({'execute': 'query-status'})['return']['status']
else:
raise IOError('Empty answer')
def _waitForVMStatus(self, wanted_status):
while True:
try:
actual_status = self._getVMStatus()
if actual_status == wanted_status:
return
else:
print 'VM in %s status, wanting it to be %s, retrying...' % (
actual_status, wanted_status)
time.sleep(1)
except IOError:
print 'VM not ready, retrying...'
def capabilities(self):
print 'Asking for capabilities...'
self._send({'execute': 'qmp_capabilities'})
def suspend(self):
print 'Suspending VM...'
self._send({'execute': 'stop'})
self._waitForVMStatus('paused')
def resume(self):
print 'Resuming VM...'
self._send({'execute': 'cont'})
self._waitForVMStatus('running')
def main():
unix_socket_location, action = parseArgument()
qemu_wrapper = QemuQMPWrapper(unix_socket_location)
if action == QMP_STOP_ACTION:
qemu_wrapper.suspend()
elif action == QMP_RESUME_ACTION:
qemu_wrapper.resume()
elif action == QMP_CAPABILITIES_ACTION:
qemu_wrapper.capabilities()
if __name__ == '__main__':
main()
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or sign in to comment