----- On Aug 22, 2017, at 7:43 PM, stefanha stefa...@redhat.com wrote:
> On Mon, Aug 21, 2017 at 04:40:37PM +0530, Ishani Chugh wrote: >> qemu-backup will be a command-line tool for performing full and >> incremental disk backups on running VMs. It is intended as a >> reference implementation for management stack and backup developers >> to see QEMU's backup features in action. The tool writes details of >> guest in a configuration file and the data is retrieved from the file >> while creating a backup. The location of config file can be set as an >> environment variable QEMU_BACKUP_CONFIG. The usage is as follows: >> >> Add a guest >> python qemu-backup.py guest add --guest <guest_name> --qmp <socket_path> >> >> Add a drive for backup in a specified guest >> python qemu-backup.py drive add --guest <guest_name> --id <drive_id> >> [--target >> <target_file_path>] >> >> Create backup of the added drives: >> python qemu-backup.py backup --guest <guest_name> >> >> List all guest configs in configuration file: >> python qemu-backup.py guest list >> >> Restore operation >> python qemu-backup.py restore --guest <guest-name> >> >> Remove a guest >> python qemu-backup.py guest remove --guest <guest_name> >> >> Signed-off-by: Ishani Chugh <chugh.ish...@research.iiit.ac.in> >> --- >> contrib/backup/qemu-backup.py | 334 >> ++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 334 insertions(+) >> create mode 100644 contrib/backup/qemu-backup.py >> >> diff --git a/contrib/backup/qemu-backup.py b/contrib/backup/qemu-backup.py >> new file mode 100644 >> index 0000000..08570f7 >> --- /dev/null >> +++ b/contrib/backup/qemu-backup.py >> @@ -0,0 +1,334 @@ >> +#!/usr/bin/python >> +# -*- coding: utf-8 -*- >> +# >> +# Copyright (C) 2017 Ishani Chugh <chugh.ish...@research.iiit.ac.in> >> +# >> +# 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 2 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, see <http://www.gnu.org/licenses/>. >> +# >> + >> +""" >> +This file is an implementation of backup tool >> +""" >> +from __future__ import print_function >> +from argparse import ArgumentParser >> +import os >> +import errno >> +from socket import error as socket_error >> +try: >> + import configparser >> +except ImportError: >> + import ConfigParser as configparser >> +import sys >> +sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', >> + 'scripts', 'qmp')) >> +from qmp import QEMUMonitorProtocol >> + >> + >> +class BackupTool(object): >> + """BackupTool Class""" >> + def __init__(self, config_file=os.path.expanduser('~') + >> + '/.config/qemu/qemu-backup-config'): >> + if "QEMU_BACKUP_CONFIG" in os.environ: >> + self.config_file = os.environ["QEMU_BACKUP_CONFIG"] >> + else: >> + self.config_file = config_file >> + try: >> + if not os.path.isdir(os.path.dirname(self.config_file)): >> + os.makedirs(os.path.dirname(self.config_file)) >> + except: >> + print("Cannot create config directory", file=sys.stderr) >> + sys.exit(1) >> + self.config = configparser.ConfigParser() >> + self.config.read(self.config_file) >> + >> + def write_config(self): >> + """ >> + Writes configuration to ini file. >> + """ >> + config_file = open(self.config_file+".tmp", 'w') >> + self.config.write(config_file) >> + config_file.flush() >> + os.fsync(config_file.fileno()) >> + config_file.close() >> + os.rename(self.config_file+".tmp", self.config_file) >> + >> + def get_socket_address(self, socket_address): >> + """ >> + Return Socket address in form of string or tuple >> + """ >> + if socket_address.startswith('tcp'): >> + return (socket_address.split(':')[1], >> + int(socket_address.split(':')[2])) >> + return socket_address.split(':', 2)[1] >> + >> + def _full_backup(self, guest_name): >> + """ >> + Performs full backup of guest >> + """ >> + if guest_name not in self.config.sections(): >> + print("Cannot find specified guest", file=sys.stderr) >> + sys.exit(1) >> + >> + self.verify_guest_running(guest_name) >> + connection = QEMUMonitorProtocol( >> + self.get_socket_address( >> + >> self.config[guest_name]['qmp'])) >> + connection.connect() >> + cmd = {"execute": "transaction", "arguments": {"actions": []}} >> + drive_list = [] >> + for key in self.config[guest_name]: >> + if key.startswith("drive_"): >> + drive = key[len('drive_'):] >> + drive_list.append(drive) >> + target = self.config[guest_name][key] >> + sub_cmd = {"type": "drive-backup", "data": {"device": drive, >> + "target": >> target, >> + "sync": "full"}} >> + cmd['arguments']['actions'].append(sub_cmd) >> + qmp_return = connection.cmd_obj(cmd) >> + if 'error' in qmp_return: >> + print(qmp_return['error']['desc'], file=sys.stderr) >> + sys.exit(1) >> + print("Backup Started") >> + while len(drive_list) != 0: >> + event = connection.pull_event(wait=True) >> + if event['event'] == 'SHUTDOWN': >> + print("The guest was SHUT DOWN", file=sys.stderr) >> + sys.exit(1) >> + >> + if event['event'] == 'RESET': >> + print("The guest was Rebooted", file=sys.stderr) >> + sys.exit(1) >> + >> + if event['data']['device'] in drive_list and \ >> + event['data']['type'] == 'backup': > > At this point the event[] dict might be a non-BLOCK_JOB_* event. > Therefore event['data']['device'] will raise a KeyError exception. > > You must check event['event'] before assuming it contains certain > fields. Agreed. Will fix in next revision. >> + if event['event'] == 'BLOCK_JOB_COMPLETED': >> + print("*"+event['data']['device']) >> + drive_list.remove(event['data']['device']) >> + elif event['event'] == 'BLOCK_JOB_ERROR': >> + print("Cannot Complete Backup", file=sys.stderr) >> + sys.exit(1) >> + print("Backup Complete") >> + >> + def _drive_add(self, drive_id, guest_name, target=None): >> + """ >> + Adds drive for backup >> + """ >> + if target is None: >> + target = os.path.abspath(drive_id) >> + >> + if os.path.isdir(os.path.dirname(target)) is False: >> + print("Cannot find target directory", file=sys.stderr) >> + sys.exit(1) >> + >> + if guest_name not in self.config.sections(): >> + print("Cannot find specified guest", file=sys.stderr) >> + sys.exit(1) >> + >> + if "drive_"+drive_id in self.config[guest_name]: >> + print("Drive already marked for backup", file=sys.stderr) >> + sys.exit(1) >> + >> + self.verify_guest_running(guest_name) >> + >> + connection = QEMUMonitorProtocol( >> + self.get_socket_address( >> + >> self.config[guest_name]['qmp'])) >> + connection.connect() >> + cmd = {'execute': 'query-block'} >> + returned_json = connection.cmd_obj(cmd) >> + device_present = False >> + for device in returned_json['return']: >> + if device['device'] == drive_id: >> + device_present = True >> + break >> + >> + if not device_present: >> + print("No such drive in guest", file=sys.stderr) >> + sys.exit(1) >> + >> + drive_id = "drive_" + drive_id >> + for d_id in self.config[guest_name]: >> + if self.config[guest_name][d_id] == target: >> + print("Please choose different target", file=sys.stderr) >> + sys.exit(1) >> + self.config.set(guest_name, drive_id, target) >> + self.write_config() >> + print("Successfully Added Drive") >> + >> + def verify_guest_running(self, guest_name): >> + """ >> + Checks whether specified guest is running or not >> + """ >> + socket_address = self.config.get(guest_name, 'qmp') >> + try: >> + connection = QEMUMonitorProtocol(self.get_socket_address( >> + socket_address)) >> + connection.connect() >> + except socket_error: >> + if socket_error.errno != errno.ECONNREFUSED: >> + print("Connection to guest refused", file=sys.stderr) >> + sys.exit(1) >> + >> + def _guest_add(self, guest_name, socket_address): >> + """ >> + Adds a guest to the config file >> + """ >> + if guest_name in self.config.sections(): >> + print("ID already exists. Please choose a different guestname", >> + file=sys.stderr) >> + sys.exit(1) >> + self.config[guest_name] = {'qmp': socket_address} >> + self.verify_guest_running(guest_name) >> + self.write_config() >> + print("Successfully Added Guest") >> + >> + def _guest_remove(self, guest_name): >> + """ >> + Removes a guest from config file >> + """ >> + if guest_name not in self.config.sections(): >> + print("Guest Not present", file=sys.stderr) >> + sys.exit(1) >> + self.config.remove_section(guest_name) >> + print("Guest successfully deleted") >> + >> + def _restore(self, guest_name): >> + """ >> + Prints Steps to perform restore operation >> + """ >> + if guest_name not in self.config.sections(): >> + print("Cannot find specified guest", file=sys.stderr) >> + sys.exit(1) >> + >> + self.verify_guest_running(guest_name) >> + connection = QEMUMonitorProtocol( >> + self.get_socket_address( >> + >> self.config[guest_name]['qmp'])) >> + connection.connect() >> + print("To perform restore, replace:") >> + for key in self.config[guest_name]: >> + if key.startswith("drive_"): >> + drive = key[len('drive_'):] >> + target = self.config[guest_name][key] >> + cmd = {'execute': 'query-block'} >> + returned_json = connection.cmd_obj(cmd) >> + device_present = False >> + for device in returned_json['return']: >> + if device['device'] == drive: >> + device_present = True >> + location = device['inserted']['image']['filename'] >> + print(location+" By "+target) > > I suggest print('Replace ' + location + ' with ' + target) for a > slightly clearer message. Will fix in next revision. >> + >> + if not device_present: >> + print("No such drive in guest", file=sys.stderr) >> + sys.exit(1) > > Since the command itself requires the guest to be running > users are very likely to manipulate the disk image files while the guest > is running. > > This command must prompt the user to shut down the guest before > restoring. The intention behind this condition is the case where user may have detached a disk from the guest(and have rerun the guest). I will put up the message to shut down the guest. >> + >> + def guest_remove_wrapper(self, args): >> + """ >> + Wrapper for _guest_remove method. >> + """ >> + guest_name = args.guest >> + self._guest_remove(guest_name) >> + self.write_config() >> + >> + def list(self, args): >> + """ >> + Prints guests present in Config file >> + """ >> + for guest_name in self.config.sections(): >> + print(guest_name) >> + >> + def guest_add_wrapper(self, args): >> + """ >> + Wrapper for _quest_add method >> + """ >> + self._guest_add(args.guest, args.qmp) >> + >> + def drive_add_wrapper(self, args): >> + """ >> + Wrapper for _drive_add method >> + """ >> + self._drive_add(args.id, args.guest, args.target) >> + >> + def fullbackup_wrapper(self, args): >> + """ >> + Wrapper for _full_backup method >> + """ >> + self._full_backup(args.guest) >> + >> + def restore_wrapper(self, args): >> + """ >> + Wrapper for restore >> + """ >> + self._restore(args.guest) >> + >> + >> +def main(): >> + backup_tool = BackupTool() >> + parser = ArgumentParser() >> + subparsers = parser.add_subparsers(title='Subcommands', >> + description='Valid Subcommands', >> + help='Subcommand help') >> + guest_parser = subparsers.add_parser('guest', help='Adds or \ >> + removes and lists >> guest(s)') >> + guest_subparsers = guest_parser.add_subparsers(title='Guest Subparser') >> + guest_list_parser = guest_subparsers.add_parser('list', >> + help='Lists all guests') >> + guest_list_parser.set_defaults(func=backup_tool.list) >> + >> + guest_add_parser = guest_subparsers.add_parser('add', help='Adds a >> guest') >> + guest_add_parser.add_argument('--guest', action='store', type=str, >> + help='Name of the guest') >> + guest_add_parser.add_argument('--qmp', action='store', type=str, >> + help='Path of socket') >> + guest_add_parser.set_defaults(func=backup_tool.guest_add_wrapper) >> + >> + guest_remove_parser = guest_subparsers.add_parser('remove', >> + help='removes a >> guest') >> + guest_remove_parser.add_argument('--guest', action='store', type=str, >> + help='Name of the guest') >> + guest_remove_parser.set_defaults(func=backup_tool.guest_remove_wrapper) >> + >> + drive_parser = subparsers.add_parser('drive', >> + help='Adds drive(s) for backup') >> + drive_subparsers = drive_parser.add_subparsers(title='Add subparser', >> + description='Drive \ >> + subparser') >> + drive_add_parser = drive_subparsers.add_parser('add', >> + help='Adds new \ >> + drive for backup') >> + drive_add_parser.add_argument('--guest', action='store', >> + type=str, help='Name of the guest') >> + drive_add_parser.add_argument('--id', action='store', >> + type=str, help='Drive ID') >> + drive_add_parser.add_argument('--target', nargs='?', >> + default=None, help='Destination path') >> + drive_add_parser.set_defaults(func=backup_tool.drive_add_wrapper) >> + >> + backup_parser = subparsers.add_parser('backup', help='Creates backup') >> + backup_parser.add_argument('--guest', action='store', >> + type=str, help='Name of the guest') >> + backup_parser.set_defaults(func=backup_tool.fullbackup_wrapper) >> + >> + backup_parser = subparsers.add_parser('restore', help='Restores drives') >> + backup_parser.add_argument('--guest', action='store', >> + type=str, help='Name of the guest') >> + backup_parser.set_defaults(func=backup_tool.restore_wrapper) >> + >> + args = parser.parse_args() >> + args.func(args) >> + >> +if __name__ == '__main__': >> + main() >> -- >> 2.7.4 Thanks for review.
