# vim: tabstop=4 shiftwidth=4 softtabstop=4 # Copyright 2010 United States Government as represented by the # Administrator of the National Aeronautics and Space Administration. # All Rights Reserved. # Copyright (c) 2010 Citrix Systems, Inc. # # Licensed under the Apache License, Version 2.0 (the "License"); you may # not use this file except in compliance with the License. You may obtain # a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the # License for the specific language governing permissions and limitations # under the License. """ Handling of VM disk images. """ import os import re from oslo.config import cfg from nova import exception from nova.image import glance from nova.openstack.common import fileutils from nova.openstack.common import log as logging from nova.openstack.common import strutils from nova import utils LOG = logging.getLogger(__name__) image_opts = [ cfg.BoolOpt('force_raw_images', default=True, help='Force backing images to raw format'), ] CONF = cfg.CONF CONF.register_opts(image_opts) class QemuImgInfo(object): BACKING_FILE_RE = re.compile((r"^(.*?)\s*\(actual\s+path\s*:" r"\s+(.*?)\)\s*$"), re.I) TOP_LEVEL_RE = re.compile(r"^([\w\d\s\_\-]+):(.*)$") SIZE_RE = re.compile(r"\(\s*(\d+)\s+bytes\s*\)", re.I) def __init__(self, cmd_output=None): details = self._parse(cmd_output or '') self.image = details.get('image') self.backing_file = details.get('backing_file') self.file_format = details.get('file_format') self.virtual_size = details.get('virtual_size') self.cluster_size = details.get('cluster_size') self.disk_size = details.get('disk_size') self.snapshots = details.get('snapshot_list', []) self.encryption = details.get('encryption') def __str__(self): lines = [ 'image: %s' % self.image, 'file_format: %s' % self.file_format, 'virtual_size: %s' % self.virtual_size, 'disk_size: %s' % self.disk_size, 'cluster_size: %s' % self.cluster_size, 'backing_file: %s' % self.backing_file, ] if self.snapshots: lines.append("snapshots: %s" % self.snapshots) return "\n".join(lines) def _canonicalize(self, field): # Standardize on underscores/lc/no dash and no spaces # since qemu seems to have mixed outputs here... and # this format allows for better integration with python # - ie for usage in kwargs and such... field = field.lower().strip() for c in (" ", "-"): field = field.replace(c, '_') return field def _extract_bytes(self, details): # Replace it with the byte amount real_size = self.SIZE_RE.search(details) if real_size: details = real_size.group(1) try: details = strutils.to_bytes(details) except TypeError: pass return details def _extract_details(self, root_cmd, root_details, lines_after): real_details = root_details if root_cmd == 'backing_file': # Replace it with the real backing file backing_match = self.BACKING_FILE_RE.match(root_details) if backing_match: real_details = backing_match.group(2).strip() elif root_cmd in ['virtual_size', 'cluster_size', 'disk_size']: # Replace it with the byte amount (if we can convert it) real_details = self._extract_bytes(root_details) elif root_cmd == 'file_format': real_details = real_details.strip().lower() elif root_cmd == 'snapshot_list': # Next line should be a header, starting with 'ID' if not lines_after or not lines_after[0].startswith("ID"): msg = _("Snapshot list encountered but no header found!") raise ValueError(msg) del lines_after[0] real_details = [] # This is the sprintf pattern we will try to match # "%-10s%-20s%7s%20s%15s" # ID TAG VM SIZE DATE VM CLOCK (current header) while lines_after: line = lines_after[0] line_pieces = line.split() if len(line_pieces) != 6: break # Check against this pattern in the final position # "%02d:%02d:%02d.%03d" date_pieces = line_pieces[5].split(":") if len(date_pieces) != 3: break real_details.append({ 'id': line_pieces[0], 'tag': line_pieces[1], 'vm_size': line_pieces[2], 'date': line_pieces[3], 'vm_clock': line_pieces[4] + " " + line_pieces[5], }) del lines_after[0] return real_details def _parse(self, cmd_output): # Analysis done of qemu-img.c to figure out what is going on here # Find all points start with some chars and then a ':' then a newline # and then handle the results of those 'top level' items in a separate # function. # # TODO(harlowja): newer versions might have a json output format # we should switch to that whenever possible. # see: http://bit.ly/XLJXDX contents = {} lines = [x for x in cmd_output.splitlines() if x.strip()] while lines: line = lines.pop(0) top_level = self.TOP_LEVEL_RE.match(line) if top_level: root = self._canonicalize(top_level.group(1)) if not root: continue root_details = top_level.group(2).strip() details = self._extract_details(root, root_details, lines) contents[root] = details return contents def qemu_img_info(path): """Return an object containing the parsed output from qemu-img info.""" if not os.path.exists(path): return QemuImgInfo() out, err = utils.execute('env', 'LC_ALL=C', 'LANG=C', 'qemu-img', 'info', path) return QemuImgInfo(out) def convert_image(source, dest, out_format, run_as_root=False): """Convert image to other format.""" cmd = ('qemu-img', 'convert', '-O', out_format, source, dest) utils.execute(*cmd, run_as_root=run_as_root) def fetch(context, image_href, path, _user_id, _project_id): # TODO(vish): Improve context handling and add owner and auth data # when it is added to glance. Right now there is no # auth checking in glance, so we assume that access was # checked before we got here. (image_service, image_id) = glance.get_remote_image_service(context, image_href) with fileutils.remove_path_on_error(path): with open(path, "wb") as image_file: image_service.download(context, image_id, image_file) def fetch_to_raw(context, image_href, path, user_id, project_id): path_tmp = "%s.part" % path fetch(context, image_href, path_tmp, user_id, project_id) with fileutils.remove_path_on_error(path_tmp): data = qemu_img_info(path_tmp) fmt = data.file_format if fmt is None: raise exception.ImageUnacceptable( reason=_("'qemu-img info' parsing failed."), image_id=image_href) backing_file = data.backing_file if backing_file is not None: raise exception.ImageUnacceptable(image_id=image_href, reason=_("fmt=%(fmt)s backed by: %(backing_file)s") % locals()) if fmt != "raw" and CONF.force_raw_images: staged = "%s.converted" % path LOG.debug("%s was %s, converting to raw" % (image_href, fmt)) with fileutils.remove_path_on_error(staged): convert_image(path_tmp, staged, 'raw') os.unlink(path_tmp) data = qemu_img_info(staged) if data.file_format != "raw": raise exception.ImageUnacceptable(image_id=image_href, reason=_("Converted to raw, but format is now %s") % data.file_format) os.rename(staged, path) else: os.rename(path_tmp, path)