novajoin/novajoin/glance.py

290 lines
9.5 KiB
Python

# Copyright 2016 Red Hat, 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.
"""Handle communication with the Glance image service."""
import copy
import inspect
import itertools
import random
import six
import sys
import time
import glanceclient.exc
from oslo_config import cfg
from oslo_log import log as logging
from oslo_serialization import jsonutils
from oslo_utils import timeutils
from novajoin import exception
from novajoin import keystone_client
CONF = cfg.CONF
LOG = logging.getLogger(__name__)
GLANCE_APIVERSION = 2
def get_api_servers():
"""Return iterator of glance api_servers.
Return iterator of glance api_servers to cycle through the
list, looping around to the beginning if necessary.
"""
api_servers = []
ks = keystone_client.get_client()
catalog = keystone_client.get_service_catalog(ks)
image_service = catalog.url_for(service_type='image')
if image_service:
api_servers.append(image_service)
if CONF.glance_api_servers:
for api_server in CONF.glance_api_servers:
api_servers.append(api_server)
random.shuffle(api_servers)
return itertools.cycle(api_servers)
class GlanceClient(object):
"""Wrapper around glance client."""
def __init__(self):
self.version = GLANCE_APIVERSION
self.api_servers = get_api_servers()
self.api_server = None
self.client = None
def _glance_client(self, context):
"""Instantiate a new glanceclient.Client object."""
if not self.api_servers:
return None
self.api_server = next(self.api_servers)
params = {}
session = keystone_client.get_session()
return glanceclient.Client(str(self.version), self.api_server,
session=session, **params)
def call(self, context, method, *args, **kwargs):
"""Call a glance client method."""
if self.client is None:
self.client = self._glance_client(context)
retry_excs = (glanceclient.exc.ServiceUnavailable,
glanceclient.exc.InvalidEndpoint,
glanceclient.exc.CommunicationError)
retries = CONF.glance_num_retries
if retries < 0:
LOG.warning("Treating negative retries as 0")
retries = 0
num_attempts = retries + 1
for attempt in range(1, num_attempts + 1):
client = self._glance_client(context)
try:
controller = getattr(client,
kwargs.pop('controller', 'images'))
result = getattr(controller, method)(*args, **kwargs)
if inspect.isgenerator(result):
# Convert generator results to a list, so that we can
# catch any potential exceptions now and retry the call.
return list(result)
return result
except retry_excs as e:
if attempt < num_attempts:
extra = "retrying"
else:
extra = "done trying"
LOG.exception("Error contacting glance server "
"'%(server)s' for '%(method)s', "
"%(extra)s.",
{'server': self.api_server,
'method': method, 'extra': extra})
if attempt == num_attempts:
raise exception.GlanceConnectionFailed(
server=str(self.api_server), reason=six.text_type(e))
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 GlanceClient()
self._image_schema = None
self.temp_images = None
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, 'list', **params)
except Exception: # pylint: disable=broad-except
_reraise_translated_exception()
else:
if images is None:
return []
_images = []
for image in images:
_images.append(self._translate_from_glance(context, 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 param in params:
_params[param] = params.get(param)
return _params
def _translate_from_glance(self, context, image):
"""Get image metadata from glance image.
Extract metadata from image and convert it's properties
to type cinder expected.
:param image: glance image object
:return: image metadata dictionary
"""
if image is None:
return {}
# Only v2 is supported in novajoin
if self._image_schema is None:
self._image_schema = self._client.call(context, 'get',
controller='schemas',
schema_name='image')
# NOTE(aarefiev): get base image property, store image 'schema'
# is redundant, so ignore it.
image_meta = {key: getattr(image, key)
for key in image.keys()
if self._image_schema.is_base_property(key) is True
and key != 'schema'}
# NOTE(aarefiev): nova is expected that all image properties
# (custom or defined in schema-image.json) stores in
# 'properties' key.
image_meta['properties'] = {
key: getattr(image, key) for key in image.keys()
if self._image_schema.is_base_property(key) is False}
image_meta = _convert_timestamps_to_datetimes(image_meta)
image_meta = _convert_from_string(image_meta)
return image_meta
def show(self, context, image_id):
"""Returns a dict with image data for the given opaque image id."""
try:
image = self._client.call(context, 'get', image_id)
except Exception: # pylint: disable=broad-except
_reraise_translated_image_exception(image_id)
else:
if image is None:
return {}
base_image_meta = self._translate_from_glance(context, image)
return base_image_meta
def _json_loads(properties, attr):
prop = properties[attr]
if isinstance(prop, six.string_types):
properties[attr] = jsonutils.loads(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_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
def _convert_from_string(metadata):
return _convert(_json_loads, metadata)
def _reraise_translated_image_exception(image_id):
"""Transform the exception for the image but keep its traceback intact."""
# pylint: disable=unused-variable
_exc_type, exc_value, exc_trace = sys.exc_info()
new_exc = _translate_image_exception(image_id, exc_value)
six.reraise(type(new_exc), new_exc, exc_trace)
def _reraise_translated_exception():
"""Transform the exception but keep its traceback intact."""
# pylint: disable=unused-variable
_exc_type, exc_value, exc_trace = sys.exc_info()
new_exc = _translate_plain_exception(exc_value)
six.reraise(type(new_exc), new_exc, 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_default_image_service():
return GlanceImageService()