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# -*- coding: utf-8 -*-
# Authors: Radostin Stoyanov <rstoyanov1@gmail.com>
#
# Copyright (C) 2017 Radostin Stoyanov
#
# 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, see <http://www.gnu.org/licenses/>.
"""
VirtBuilderSource aim is to extract the root file system from VM image
build with virt-builder from template.
"""
import os
import logging
import subprocess
import tempfile
import guestfs
from virtBootstrap import utils
# pylint: disable=invalid-name
# Create logger
logger = logging.getLogger(__name__)
class VirtBuilderSource(object):
"""
Extract root file system from image build with virt-builder.
"""
def __init__(self, **kwargs):
"""
Create container rootfs by building VM from virt-builder template
and extract the rootfs.
@param uri: Template name
@param fmt: Format used to store the output [dir, qcow2]
@param uid_map: Mappings for UID of files in rootfs
@param gid_map: Mappings for GID of files in rootfs
@param root_password: Root password to set in rootfs
@param progress: Instance of the progress module
"""
# Parsed URIs:
# - "virt-builder:///<template>"
# - "virt-builder://<template>"
# - "virt-builder:/<template>"
self.template = kwargs['uri'].netloc or kwargs['uri'].path[1:]
self.output_format = kwargs.get('fmt', utils.DEFAULT_OUTPUT_FORMAT)
self.uid_map = kwargs.get('uid_map', [])
self.gid_map = kwargs.get('gid_map', [])
self.root_password = kwargs.get('root_password', None)
self.progress = kwargs['progress'].update_progress
def build_image(self, output_file):
"""
Build VM from virt-builder template
"""
cmd = ['virt-builder', self.template,
'-o', output_file,
'--no-network',
'--delete', '/dev/*',
'--delete', '/boot/*',
# Comment out all lines in fstab
'--edit', '/etc/fstab:s/^/#/']
if self.root_password is not None:
cmd += ['--root-password', "password:%s" % self.root_password]
self.run_builder(cmd)
def run_builder(self, cmd):
"""
Execute virt-builder command
"""
subprocess.check_call(cmd)
def unpack(self, dest):
"""
Build image and extract root file system
@param dest: Directory path where output files will be stored.
"""
with tempfile.NamedTemporaryFile(prefix='bootstrap_') as tmp_file:
if self.output_format == 'dir':
self.progress("Building image", value=0, logger=logger)
self.build_image(tmp_file.name)
self.progress("Extracting rootfs", value=50, logger=logger)
g = guestfs.GuestFS(python_return_dict=True)
g.add_drive_opts(tmp_file.name, readonly=False, format='raw')
g.launch()
# Get the device with file system
root_dev = g.inspect_os()
if not root_dev:
raise Exception("No file system was found")
g.mount(root_dev[0], '/')
# Extract file system to destination directory
g.copy_out('/', dest)
g.umount('/')
g.shutdown()
self.progress("Extraction completed successfully!",
value=100, logger=logger)
logger.info("Files are stored in: %s", dest)
elif self.output_format == 'qcow2':
output_file = os.path.join(dest, 'layer-0.qcow2')
self.progress("Building image", value=0, logger=logger)
self.build_image(tmp_file.name)
self.progress("Extracting rootfs", value=50, logger=logger)
g = guestfs.GuestFS(python_return_dict=True)
g.add_drive_opts(tmp_file.name, readonly=True, format='raw')
# Create qcow2 disk image
g.disk_create(
filename=output_file,
format='qcow2',
size=os.path.getsize(tmp_file.name)
)
g.add_drive_opts(output_file, readonly=False, format='qcow2')
g.launch()
# Get the device with file system
root_dev = g.inspect_os()
if not root_dev:
raise Exception("No file system was found")
output_dev = g.list_devices()[1]
# Copy the file system to the new qcow2 disk
g.copy_device_to_device(root_dev[0], output_dev, sparse=True)
g.shutdown()
# UID/GID mapping
if self.uid_map or self.gid_map:
logger.info("Mapping UID/GID")
utils.map_id_in_image(1, dest, self.uid_map, self.gid_map)
self.progress("Extraction completed successfully!", value=100,
logger=logger)
logger.info("Image is stored in: %s", output_file)
else:
raise Exception("Unknown format:" + self.output_format)
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