Files
nova/nova/image/glance.py
Eugene Nikanorov 20eac6c1df Remove locals() from various places.
fixes bug 1171936

Remove usage of locals() for string formatting

Change-Id: Ib05538095086ddefdb486c84da506af662ec5c9b
2013-07-17 09:30:48 +04:00

520 lines
18 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2010 OpenStack Foundation
# All Rights Reserved.
#
# 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.
"""Implementation of an image service that uses Glance as the backend."""
from __future__ import absolute_import
import copy
import itertools
import random
import shutil
import sys
import time
import urlparse
import glanceclient
import glanceclient.exc
from oslo.config import cfg
from nova import exception
from nova.openstack.common import jsonutils
from nova.openstack.common import log as logging
from nova.openstack.common import timeutils
glance_opts = [
cfg.StrOpt('glance_host',
default='$my_ip',
help='default glance hostname or ip'),
cfg.IntOpt('glance_port',
default=9292,
help='default glance port'),
cfg.StrOpt('glance_protocol',
default='http',
help='Default protocol to use when connecting to glance. '
'Set to https for SSL.'),
cfg.ListOpt('glance_api_servers',
default=['$glance_host:$glance_port'],
help='A list of the glance api servers available to nova. '
'Prefix with https:// for ssl-based glance api servers. '
'([hostname|ip]:port)'),
cfg.BoolOpt('glance_api_insecure',
default=False,
help='Allow to perform insecure SSL (https) requests to '
'glance'),
cfg.IntOpt('glance_num_retries',
default=0,
help='Number retries when downloading an image from glance'),
cfg.ListOpt('allowed_direct_url_schemes',
default=[],
help='A list of url scheme that can be downloaded directly '
'via the direct_url. Currently supported schemes: '
'[file].'),
]
LOG = logging.getLogger(__name__)
CONF = cfg.CONF
CONF.register_opts(glance_opts)
CONF.import_opt('auth_strategy', 'nova.api.auth')
CONF.import_opt('my_ip', 'nova.netconf')
def generate_glance_url():
"""Generate the URL to glance."""
return "%s://%s:%d" % (CONF.glance_protocol, CONF.glance_host,
CONF.glance_port)
def generate_image_url(image_ref):
"""Generate an image URL from an image_ref."""
return "%s/images/%s" % (generate_glance_url(), image_ref)
def _parse_image_ref(image_href):
"""Parse an image href into composite parts.
:param image_href: href of an image
:returns: a tuple of the form (image_id, host, port)
:raises ValueError
"""
o = urlparse.urlparse(image_href)
port = o.port or 80
host = o.netloc.split(':', 1)[0]
image_id = o.path.split('/')[-1]
use_ssl = (o.scheme == 'https')
return (image_id, host, port, use_ssl)
def _create_glance_client(context, host, port, use_ssl, version=1):
"""Instantiate a new glanceclient.Client object."""
if use_ssl:
scheme = 'https'
else:
scheme = 'http'
params = {}
params['insecure'] = CONF.glance_api_insecure
if CONF.auth_strategy == 'keystone':
params['token'] = context.auth_token
endpoint = '%s://%s:%s' % (scheme, host, port)
return glanceclient.Client(str(version), endpoint, **params)
def get_api_servers():
"""
Shuffle a list of CONF.glance_api_servers and return an iterator
that will cycle through the list, looping around to the beginning
if necessary.
"""
api_servers = []
for api_server in CONF.glance_api_servers:
if '//' not in api_server:
api_server = 'http://' + api_server
o = urlparse.urlparse(api_server)
port = o.port or 80
host = o.netloc.split(':', 1)[0]
use_ssl = (o.scheme == 'https')
api_servers.append((host, port, use_ssl))
random.shuffle(api_servers)
return itertools.cycle(api_servers)
class GlanceClientWrapper(object):
"""Glance client wrapper class that implements retries."""
def __init__(self, context=None, host=None, port=None, use_ssl=False,
version=1):
if host is not None:
self.client = self._create_static_client(context,
host, port,
use_ssl, version)
else:
self.client = None
self.api_servers = None
def _create_static_client(self, context, host, port, use_ssl, version):
"""Create a client that we'll use for every call."""
self.host = host
self.port = port
self.use_ssl = use_ssl
self.version = version
return _create_glance_client(context,
self.host, self.port,
self.use_ssl, self.version)
def _create_onetime_client(self, context, version):
"""Create a client that will be used for one call."""
if self.api_servers is None:
self.api_servers = get_api_servers()
self.host, self.port, self.use_ssl = self.api_servers.next()
return _create_glance_client(context,
self.host, self.port,
self.use_ssl, version)
def call(self, context, version, method, *args, **kwargs):
"""
Call a glance client method. If we get a connection error,
retry the request according to CONF.glance_num_retries.
"""
retry_excs = (glanceclient.exc.ServiceUnavailable,
glanceclient.exc.InvalidEndpoint,
glanceclient.exc.CommunicationError)
num_attempts = 1 + CONF.glance_num_retries
for attempt in xrange(1, num_attempts + 1):
client = self.client or self._create_onetime_client(context,
version)
try:
return getattr(client.images, method)(*args, **kwargs)
except retry_excs as e:
host = self.host
port = self.port
extra = "retrying"
error_msg = (_("Error contacting glance server "
"'%(host)s:%(port)s' for '%(method)s', "
"%(extra)s.") %
{'host': host, 'port': port,
'method': method, 'extra': extra})
if attempt == num_attempts:
extra = 'done trying'
LOG.exception(error_msg)
raise exception.GlanceConnectionFailed(
host=host, port=port, reason=str(e))
LOG.exception(error_msg)
time.sleep(1)
class GlanceImageService(object):
"""Provides storage and retrieval of disk image objects within Glance."""
def __init__(self, client=None):
self._client = client or GlanceClientWrapper()
def detail(self, context, **kwargs):
"""Calls out to Glance for a list of detailed image information."""
params = self._extract_query_params(kwargs)
try:
images = self._client.call(context, 1, 'list', **params)
except Exception:
_reraise_translated_exception()
_images = []
for image in images:
if self._is_image_available(context, image):
_images.append(self._translate_from_glance(image))
return _images
def _extract_query_params(self, params):
_params = {}
accepted_params = ('filters', 'marker', 'limit',
'sort_key', 'sort_dir')
for param in accepted_params:
if params.get(param):
_params[param] = params.get(param)
# ensure filters is a dict
_params.setdefault('filters', {})
# NOTE(vish): don't filter out private images
_params['filters'].setdefault('is_public', 'none')
return _params
def show(self, context, image_id):
"""Returns a dict with image data for the given opaque image id."""
try:
image = self._client.call(context, 1, 'get', image_id)
except Exception:
_reraise_translated_image_exception(image_id)
if not self._is_image_available(context, image):
raise exception.ImageNotFound(image_id=image_id)
base_image_meta = self._translate_from_glance(image)
return base_image_meta
def get_location(self, context, image_id):
"""Returns the direct url representing the backend storage location,
or None if this attribute is not shown by Glance.
"""
try:
client = GlanceClientWrapper()
image_meta = client.call(context, 2, 'get', image_id)
except Exception:
_reraise_translated_image_exception(image_id)
if not self._is_image_available(context, image_meta):
raise exception.ImageNotFound(image_id=image_id)
return getattr(image_meta, 'direct_url', None)
def download(self, context, image_id, data=None):
"""Calls out to Glance for data and writes data."""
if 'file' in CONF.allowed_direct_url_schemes:
location = self.get_location(context, image_id)
o = urlparse.urlparse(location)
if o.scheme == "file":
with open(o.path, "r") as f:
# FIXME(jbresnah) a system call to cp could have
# significant performance advantages, however we
# do not have the path to files at this point in
# the abstraction.
shutil.copyfileobj(f, data)
return
try:
image_chunks = self._client.call(context, 1, 'data', image_id)
except Exception:
_reraise_translated_image_exception(image_id)
if data is None:
return image_chunks
else:
for chunk in image_chunks:
data.write(chunk)
def create(self, context, image_meta, data=None):
"""Store the image data and return the new image object."""
sent_service_image_meta = self._translate_to_glance(image_meta)
if data:
sent_service_image_meta['data'] = data
try:
recv_service_image_meta = self._client.call(
context, 1, 'create', **sent_service_image_meta)
except glanceclient.exc.HTTPException:
_reraise_translated_exception()
return self._translate_from_glance(recv_service_image_meta)
def update(self, context, image_id, image_meta, data=None,
purge_props=True):
"""Modify the given image with the new data."""
image_meta = self._translate_to_glance(image_meta)
image_meta['purge_props'] = purge_props
#NOTE(bcwaldon): id is not an editable field, but it is likely to be
# passed in by calling code. Let's be nice and ignore it.
image_meta.pop('id', None)
if data:
image_meta['data'] = data
try:
image_meta = self._client.call(context, 1, 'update',
image_id, **image_meta)
except Exception:
_reraise_translated_image_exception(image_id)
else:
return self._translate_from_glance(image_meta)
def delete(self, context, image_id):
"""Delete the given image.
:raises: ImageNotFound if the image does not exist.
:raises: NotAuthorized if the user is not an owner.
:raises: ImageNotAuthorized if the user is not authorized.
"""
try:
self._client.call(context, 1, 'delete', image_id)
except glanceclient.exc.NotFound:
raise exception.ImageNotFound(image_id=image_id)
except glanceclient.exc.HTTPForbidden:
raise exception.ImageNotAuthorized(image_id=image_id)
return True
@staticmethod
def _translate_to_glance(image_meta):
image_meta = _convert_to_string(image_meta)
image_meta = _remove_read_only(image_meta)
return image_meta
@staticmethod
def _translate_from_glance(image):
image_meta = _extract_attributes(image)
image_meta = _convert_timestamps_to_datetimes(image_meta)
image_meta = _convert_from_string(image_meta)
return image_meta
@staticmethod
def _is_image_available(context, image):
"""Check image availability.
This check is needed in case Nova and Glance are deployed
without authentication turned on.
"""
# The presence of an auth token implies this is an authenticated
# request and we need not handle the noauth use-case.
if hasattr(context, 'auth_token') and context.auth_token:
return True
if image.is_public or context.is_admin:
return True
properties = image.properties
if context.project_id and ('owner_id' in properties):
return str(properties['owner_id']) == str(context.project_id)
if context.project_id and ('project_id' in properties):
return str(properties['project_id']) == str(context.project_id)
try:
user_id = properties['user_id']
except KeyError:
return False
return str(user_id) == str(context.user_id)
def _convert_timestamps_to_datetimes(image_meta):
"""Returns image with timestamp fields converted to datetime objects."""
for attr in ['created_at', 'updated_at', 'deleted_at']:
if image_meta.get(attr):
image_meta[attr] = timeutils.parse_isotime(image_meta[attr])
return image_meta
# NOTE(bcwaldon): used to store non-string data in glance metadata
def _json_loads(properties, attr):
prop = properties[attr]
if isinstance(prop, basestring):
properties[attr] = jsonutils.loads(prop)
def _json_dumps(properties, attr):
prop = properties[attr]
if not isinstance(prop, basestring):
properties[attr] = jsonutils.dumps(prop)
_CONVERT_PROPS = ('block_device_mapping', 'mappings')
def _convert(method, metadata):
metadata = copy.deepcopy(metadata)
properties = metadata.get('properties')
if properties:
for attr in _CONVERT_PROPS:
if attr in properties:
method(properties, attr)
return metadata
def _convert_from_string(metadata):
return _convert(_json_loads, metadata)
def _convert_to_string(metadata):
return _convert(_json_dumps, metadata)
def _extract_attributes(image):
IMAGE_ATTRIBUTES = ['size', 'disk_format', 'owner',
'container_format', 'checksum', 'id',
'name', 'created_at', 'updated_at',
'deleted_at', 'deleted', 'status',
'min_disk', 'min_ram', 'is_public']
output = {}
for attr in IMAGE_ATTRIBUTES:
output[attr] = getattr(image, attr, None)
output['properties'] = getattr(image, 'properties', {})
return output
def _remove_read_only(image_meta):
IMAGE_ATTRIBUTES = ['status', 'updated_at', 'created_at', 'deleted_at']
output = copy.deepcopy(image_meta)
for attr in IMAGE_ATTRIBUTES:
if attr in output:
del output[attr]
return output
def _reraise_translated_image_exception(image_id):
"""Transform the exception for the image but keep its traceback intact."""
exc_type, exc_value, exc_trace = sys.exc_info()
new_exc = _translate_image_exception(image_id, exc_value)
raise new_exc, None, exc_trace
def _reraise_translated_exception():
"""Transform the exception but keep its traceback intact."""
exc_type, exc_value, exc_trace = sys.exc_info()
new_exc = _translate_plain_exception(exc_value)
raise new_exc, None, exc_trace
def _translate_image_exception(image_id, exc_value):
if isinstance(exc_value, (glanceclient.exc.Forbidden,
glanceclient.exc.Unauthorized)):
return exception.ImageNotAuthorized(image_id=image_id)
if isinstance(exc_value, glanceclient.exc.NotFound):
return exception.ImageNotFound(image_id=image_id)
if isinstance(exc_value, glanceclient.exc.BadRequest):
return exception.Invalid(exc_value)
return exc_value
def _translate_plain_exception(exc_value):
if isinstance(exc_value, (glanceclient.exc.Forbidden,
glanceclient.exc.Unauthorized)):
return exception.NotAuthorized(exc_value)
if isinstance(exc_value, glanceclient.exc.NotFound):
return exception.NotFound(exc_value)
if isinstance(exc_value, glanceclient.exc.BadRequest):
return exception.Invalid(exc_value)
return exc_value
def get_remote_image_service(context, image_href):
"""Create an image_service and parse the id from the given image_href.
The image_href param can be an href of the form
'http://example.com:9292/v1/images/b8b2c6f7-7345-4e2f-afa2-eedaba9cbbe3',
or just an id such as 'b8b2c6f7-7345-4e2f-afa2-eedaba9cbbe3'. If the
image_href is a standalone id, then the default image service is returned.
:param image_href: href that describes the location of an image
:returns: a tuple of the form (image_service, image_id)
"""
# Calling out to another service may take a while, so lets log this
LOG.debug(_("fetching image %s from glance") % image_href)
#NOTE(bcwaldon): If image_href doesn't look like a URI, assume its a
# standalone image ID
if '/' not in str(image_href):
image_service = get_default_image_service()
return image_service, image_href
try:
(image_id, glance_host, glance_port, use_ssl) = \
_parse_image_ref(image_href)
glance_client = GlanceClientWrapper(context=context,
host=glance_host, port=glance_port, use_ssl=use_ssl)
except ValueError:
raise exception.InvalidImageRef(image_href=image_href)
image_service = GlanceImageService(client=glance_client)
return image_service, image_id
def get_default_image_service():
return GlanceImageService()