glance_store/glance_store/multi_backend.py
Abhishek Kekane bb4587392a Add interface to get store weight from memory
Some of the available glance stores like file, cinder etc has
capability to reuse already initiated driver
(DRIVER_REUSABLE = 0b01000000). In Caracal we have added a
feature to sort image locations based on store weight. As RBD
driver of glance does not have this reuse capability, during
image list API call it initializes the RBD driver for each of
the available image which is causing noticable delay in list
call.

To avoid this, introducing new interface in glance_store which
will directly get the weight of the store from memory and return
it back to user.

NOTE: Since the current module does not have any test coverage,
corresponding tests will be added in glance once we release
glance_store with this change.

Related-Bug: #2086675
Change-Id: If6861f3271f50680af271090b516f2add6e392b9
2024-11-13 05:32:18 +00:00

626 lines
23 KiB
Python

# Copyright 2018 RedHat Inc.
# 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.
import copy
import hashlib
import logging
from oslo_config import cfg
from oslo_utils import encodeutils
from oslo_utils import units
from stevedore import driver
from stevedore import extension
from glance_store import capabilities
from glance_store import exceptions
from glance_store.i18n import _
from glance_store import location
CONF = cfg.CONF
LOG = logging.getLogger(__name__)
_STORE_OPTS = [
cfg.StrOpt('default_backend',
help=_("""
The store identifier for the default backend in which data will be
stored.
The value must be defined as one of the keys in the dict defined
by the ``enabled_backends`` configuration option in the DEFAULT
configuration group.
If a value is not defined for this option:
* the consuming service may refuse to start
* store_add calls that do not specify a specific backend will
raise a ``glance_store.exceptions.UnknownScheme`` exception
Related Options:
* enabled_backends
""")),
]
FS_CONF_DATADIR_HELP = """
Directory of which the reserved store {} uses.
Possible values:
* A valid path to a directory
Refer to [glance_store]/filesystem store config opts for more details.
"""
FS_CONF_CHUNKSIZE_HELP = """
Chunk size, in bytes to be used by reserved store {}.
The chunk size used when reading or writing image files. Raising this value
may improve the throughput but it may also slightly increase the memory usage
when handling a large number of requests.
Possible Values:
* Any positive integer value
"""
_STORE_CFG_GROUP = 'glance_store'
_RESERVED_STORES = {}
def _list_config_opts():
# NOTE(abhishekk): This separated approach could list
# store options before all driver ones, which easier
# to generate sampe config file.
driver_opts = _list_driver_opts()
sample_opts = [(_STORE_CFG_GROUP, _STORE_OPTS)]
for store_entry in driver_opts:
# NOTE(abhishekk): Do not include no_conf store
if store_entry == "no_conf":
continue
sample_opts.append((store_entry, driver_opts[store_entry]))
return sample_opts
def _list_driver_opts():
driver_opts = {}
mgr = extension.ExtensionManager('glance_store.drivers')
# NOTE(zhiyan): Handle available drivers entry_points provided
# NOTE(nikhil): Return a sorted list of drivers to ensure that the sample
# configuration files generated by oslo config generator retain the order
# in which the config opts appear across different runs. If this order of
# config opts is not preserved, some downstream packagers may see a long
# diff of the changes though not relevant as only order has changed. See
# some more details at bug 1619487.
drivers = sorted([ext.name for ext in mgr])
handled_drivers = [] # Used to handle backwards-compatible entries
for store_entry in drivers:
driver_cls = _load_multi_store(None, store_entry, False)
if driver_cls and driver_cls not in handled_drivers:
if getattr(driver_cls, 'OPTIONS', None) is not None:
driver_opts[store_entry] = driver_cls.OPTIONS
handled_drivers.append(driver_cls)
# NOTE(zhiyan): This separated approach could list
# store options before all driver ones, which easier
# to read and configure by operator.
return driver_opts
def register_store_opts(conf, reserved_stores=None):
LOG.debug("Registering options for group %s", _STORE_CFG_GROUP)
conf.register_opts(_STORE_OPTS, group=_STORE_CFG_GROUP)
configured_backends = copy.deepcopy(conf.enabled_backends)
if reserved_stores:
conf.enabled_backends.update(reserved_stores)
for key in reserved_stores.keys():
fs_conf_template = [
cfg.StrOpt('filesystem_store_datadir',
default='/var/lib/glance/{}'.format(key),
help=FS_CONF_DATADIR_HELP.format(key)),
cfg.MultiStrOpt('filesystem_store_datadirs',
help="""Not used"""),
cfg.StrOpt('filesystem_store_metadata_file',
help="""Not used"""),
cfg.IntOpt('filesystem_store_file_perm',
default=0,
help="""Not used"""),
cfg.IntOpt('filesystem_store_chunk_size',
default=64 * units.Ki,
min=1,
help=FS_CONF_CHUNKSIZE_HELP.format(key)),
cfg.BoolOpt('filesystem_thin_provisioning',
default=False,
help="""Not used""")]
LOG.debug("Registering options for reserved store: {}".format(key))
conf.register_opts(fs_conf_template, group=key)
driver_opts = _list_driver_opts()
for backend in configured_backends:
for opt_list in driver_opts:
if configured_backends[backend] not in opt_list:
continue
LOG.debug("Registering options for group %s", backend)
conf.register_opts(driver_opts[opt_list], group=backend)
def _load_multi_store(conf, store_entry,
invoke_load=True,
backend=None):
if backend:
invoke_args = [conf, backend]
else:
invoke_args = [conf]
try:
LOG.debug("Attempting to import store %s", store_entry)
mgr = driver.DriverManager('glance_store.drivers',
store_entry,
invoke_args=invoke_args,
invoke_on_load=invoke_load)
return mgr.driver
except RuntimeError as e:
LOG.warning("Failed to load driver %(driver)s. The "
"driver will be disabled", dict(driver=str([driver, e])))
def _load_multi_stores(conf, reserved_stores=None):
enabled_backends = conf.enabled_backends
if reserved_stores:
enabled_backends.update(reserved_stores)
_RESERVED_STORES.update(reserved_stores)
for backend, store_entry in enabled_backends.items():
try:
# FIXME(flaper87): Don't hide BadStoreConfiguration
# exceptions. These exceptions should be propagated
# to the user of the library.
store_instance = _load_multi_store(conf, store_entry,
backend=backend)
if not store_instance:
continue
yield (store_entry, store_instance, backend)
except exceptions.BadStoreConfiguration:
continue
def create_multi_stores(conf=CONF, reserved_stores=None):
"""
Registers all store modules and all schemes from the given configuration
object.
:param conf: A oslo_config (or compatible) object
:param reserved_stores: A list of stores for the consuming service's
internal use. The list must be the same
format as the ``enabled_backends`` configuration
setting. The default value is None
:return: The number of stores configured
:raises: ``glance_store.exceptions.BackendException``
*Configuring Multiple Backends*
The backends to be configured are expected to be found in the
``enabled_backends`` configuration variable in the DEFAULT group
of the object. The format for the variable is a dictionary of
key:value pairs where the key is an arbitrary store identifier
and the value is the store type identifier for the store.
The type identifiers must be defined in the ``[entry points]``
section of the glance_store ``setup.cfg`` file as values for
the ``glance_store.drivers`` configuration. (See the default
``setup.cfg`` file for an example.) The store type identifiers
for the currently supported drivers are already defined in the file.
Thus an example value for ``enabled_backends`` is::
{'store_one': 'http', 'store_two': 'file', 'store_three': 'rbd'}
The ``reserved_stores`` parameter, if included, must have the same
format. There is no difference between the ``enabled_backends`` and
``reserved_stores`` from the glance_store point of view: the reserved
stores are a convenience for the consuming service, which may wish
to handle the two sets of stores differently.
*The Default Store*
If you wish to set a default store, its store identifier should be
defined as the value of the ``default_backend`` configuration option
in the ``glance_store`` group of the ``conf`` parameter. The store
identifier, or course, should be specified as one of the keys in the
``enabled_backends`` dict. It is recommended that a default store
be set.
*Configuring Individual Backends*
To configure each store mentioned in the ``enabled_backends``
configuration option, you must define an option group with the
same name as the store identifier. The options defined for that
backend will depend upon the store type; consult the documentation
for the appropriate backend driver to determine what these are.
For example, given the ``enabled_backends`` example above, you
would put the following in the configuration file that loads the
``conf`` object::
[DEFAULT]
enabled_backends = store_one:rbd,store_two:file,store_three:http
[store_one]
store_description = "A human-readable string aimed at end users"
rbd_store_chunk_size = 8
rbd_store_pool = images
rbd_store_user = admin
rbd_store_ceph_conf = /etc/ceph/ceph.conf
[store_two]
store_description = "Human-readable description of this store"
filesystem_store_datadir = /opt/stack/data/glance/store_two
[store_three]
store_description = "A read-only store"
https_ca_certificates_file = /opt/stack/certs/gs.cert
[glance_store]
default_backend = store_two
The ``store_description`` options may be used by a consuming service.
As recommended above, this file also defines a default backend.
"""
store_count = 0
scheme_map = {}
for (store_entry, store_instance,
store_identifier) in _load_multi_stores(
conf, reserved_stores=reserved_stores):
try:
schemes = store_instance.get_schemes()
store_instance.configure(re_raise_bsc=False)
except NotImplementedError:
continue
if not schemes:
raise exceptions.BackendException(
_('Unable to register store %s. No schemes associated '
'with it.') % store_entry)
else:
LOG.debug("Registering store %s with schemes %s",
store_entry, schemes)
loc_cls = store_instance.get_store_location_class()
for scheme in schemes:
if scheme not in scheme_map:
scheme_map[scheme] = {}
scheme_map[scheme][store_identifier] = {
'store': store_instance,
'location_class': loc_cls,
'store_entry': store_entry
}
location.register_scheme_backend_map(scheme_map)
store_count += 1
return store_count
def verify_store():
store_id = CONF.glance_store.default_backend
if not store_id:
msg = _("'default_backend' config option is not set.")
raise RuntimeError(msg)
try:
get_store_from_store_identifier(store_id)
except exceptions.UnknownScheme:
msg = _("Store for identifier %s not found") % store_id
raise RuntimeError(msg)
def get_store_weight(store_identifier):
"""Determine backing store weightage from identifier.
Given a store identifier, return the appropriate weight of store
from memory.
"""
enabled_backends = CONF.enabled_backends
enabled_backends.update(_RESERVED_STORES)
try:
scheme = enabled_backends[store_identifier]
except KeyError:
msg = _("Store for identifier %s not found") % store_identifier
raise exceptions.UnknownScheme(msg)
try:
backend_map = location.SCHEME_TO_CLS_BACKEND_MAP[scheme]
scheme_info = backend_map[store_identifier]
except KeyError:
raise exceptions.UnknownScheme(scheme=scheme)
store = scheme_info['store']
if store:
return store.weight
return 0
def get_store_from_store_identifier(store_identifier):
"""Determine backing store from identifier.
Given a store identifier, return the appropriate store object
for handling that scheme.
"""
scheme_map = {}
enabled_backends = CONF.enabled_backends
enabled_backends.update(_RESERVED_STORES)
try:
scheme = enabled_backends[store_identifier]
except KeyError:
msg = _("Store for identifier %s not found") % store_identifier
raise exceptions.UnknownScheme(msg)
if scheme not in location.SCHEME_TO_CLS_BACKEND_MAP:
raise exceptions.UnknownScheme(scheme=scheme)
scheme_info = location.SCHEME_TO_CLS_BACKEND_MAP[scheme][store_identifier]
store = scheme_info['store']
if not store.is_capable(capabilities.BitMasks.DRIVER_REUSABLE):
# Driver instance isn't stateless so it can't
# be reused safely and need recreation.
store_entry = scheme_info['store_entry']
store = _load_multi_store(store.conf, store_entry, invoke_load=True,
backend=store_identifier)
store.configure()
try:
loc_cls = store.get_store_location_class()
for new_scheme in store.get_schemes():
if new_scheme not in scheme_map:
scheme_map[new_scheme] = {}
scheme_map[new_scheme][store_identifier] = {
'store': store,
'location_class': loc_cls,
'store_entry': store_entry
}
location.register_scheme_backend_map(scheme_map)
except NotImplementedError:
scheme_info['store'] = store
return store
def add(conf, image_id, data, size, backend, context=None,
verifier=None):
if not backend:
backend = conf.glance_store.default_backend
store = get_store_from_store_identifier(backend)
return store_add_to_backend(image_id, data, size, store, context,
verifier)
def add_with_multihash(conf, image_id, data, size, backend, hashing_algo,
scheme=None, context=None, verifier=None):
if not backend:
backend = conf.glance_store.default_backend
store = get_store_from_store_identifier(backend)
return store_add_to_backend_with_multihash(
image_id, data, size, hashing_algo, store, context, verifier)
def _check_metadata(store, metadata):
if not isinstance(metadata, dict):
msg = (_("The storage driver %(driver)s returned invalid "
" metadata %(metadata)s. This must be a dictionary type")
% dict(driver=str(store), metadata=str(metadata)))
LOG.error(msg)
raise exceptions.BackendException(msg)
try:
check_location_metadata(metadata)
except exceptions.BackendException as e:
e_msg = (_("A bad metadata structure was returned from the "
"%(driver)s storage driver: %(metadata)s. %(e)s.") %
dict(driver=encodeutils.exception_to_unicode(store),
metadata=encodeutils.exception_to_unicode(metadata),
e=encodeutils.exception_to_unicode(e)))
LOG.error(e_msg)
raise exceptions.BackendException(e_msg)
def store_add_to_backend(image_id, data, size, store, context=None,
verifier=None):
"""A wrapper around a call to each stores add() method.
This gives glance a common place to check the output.
:param image_id: The image add to which data is added
:param data: The data to be stored
:param size: The length of the data in bytes
:param store: The store to which the data is being added
:param context: The request context
:param verifier: An object used to verify signatures for images
:param backend: Name of the backend to store the image
:return: The url location of the file,
the size amount of data,
the checksum of the data
the storage systems metadata dictionary for the location
"""
(location, size, checksum, metadata) = store.add(image_id,
data,
size,
context=context,
verifier=verifier)
if metadata is not None:
_check_metadata(store, metadata)
return (location, size, checksum, metadata)
def store_add_to_backend_with_multihash(
image_id, data, size, hashing_algo, store,
context=None, verifier=None):
"""
A wrapper around a call to each store's add() method that requires
a hashing_algo identifier and returns a 5-tuple including the
"multihash" computed using the specified hashing_algo. (This
is an enhanced version of store_add_to_backend(), which is left
as-is for backward compatibility.)
:param image_id: The image add to which data is added
:param data: The data to be stored
:param size: The length of the data in bytes
:param store: The store to which the data is being added
:param hashing_algo: A hashlib algorithm identifier (string)
:param context: The request context
:param verifier: An object used to verify signatures for images
:return: The url location of the file,
the size amount of data,
the checksum of the data,
the multihash of the data,
the storage system's metadata dictionary for the location
:raises: ``glance_store.exceptions.BackendException``
``glance_store.exceptions.UnknownHashingAlgo``
"""
if hashing_algo not in hashlib.algorithms_available:
raise exceptions.UnknownHashingAlgo(algo=hashing_algo)
(location, size, checksum, multihash, metadata) = store.add(
image_id, data, size, hashing_algo, context=context, verifier=verifier)
if metadata is not None:
_check_metadata(store, metadata)
return (location, size, checksum, multihash, metadata)
def check_location_metadata(val, key=''):
if isinstance(val, dict):
for key in val:
check_location_metadata(val[key], key=key)
elif isinstance(val, list):
ndx = 0
for v in val:
check_location_metadata(v, key='%s[%d]' % (key, ndx))
ndx = ndx + 1
elif not isinstance(val, str):
raise exceptions.BackendException(_("The image metadata key %(key)s "
"has an invalid type of %(type)s. "
"Only dict, list, and unicode are "
"supported.")
% dict(key=key, type=type(val)))
def delete(uri, backend, context=None):
"""Removes chunks of data from backend specified by uri."""
if backend:
loc = location.get_location_from_uri_and_backend(
uri, backend, conf=CONF)
store = get_store_from_store_identifier(backend)
return store.delete(loc, context=context)
LOG.warning('Backend is not set to image, searching all backends based on '
'location URI.')
backends = CONF.enabled_backends
for backend in backends:
try:
if not uri.startswith(backends[backend]):
continue
loc = location.get_location_from_uri_and_backend(
uri, backend, conf=CONF)
store = get_store_from_store_identifier(backend)
return store.delete(loc, context=context)
except (exceptions.NotFound, exceptions.UnknownScheme):
continue
raise exceptions.NotFound(_("Image not found in any configured backend"))
def set_acls_for_multi_store(location_uri, backend, public=False,
read_tenants=[],
write_tenants=None, context=None):
if write_tenants is None:
write_tenants = []
loc = location.get_location_from_uri_and_backend(
location_uri, backend, conf=CONF)
store = get_store_from_store_identifier(backend)
try:
store.set_acls(loc, public=public,
read_tenants=read_tenants,
write_tenants=write_tenants,
context=context)
except NotImplementedError:
LOG.debug("Skipping store.set_acls... not implemented")
def get(uri, backend, offset=0, chunk_size=None, context=None):
"""Yields chunks of data from backend specified by uri."""
if backend:
loc = location.get_location_from_uri_and_backend(uri, backend,
conf=CONF)
store = get_store_from_store_identifier(backend)
return store.get(loc, offset=offset,
chunk_size=chunk_size,
context=context)
LOG.warning('Backend is not set to image, searching all backends based on '
'location URI.')
backends = CONF.enabled_backends
for backend in backends:
try:
if not uri.startswith(backends[backend]):
continue
loc = location.get_location_from_uri_and_backend(
uri, backend, conf=CONF)
store = get_store_from_store_identifier(backend)
data, size = store.get(loc, offset=offset,
chunk_size=chunk_size,
context=context)
if data:
return data, size
except (exceptions.NotFound, exceptions.UnknownScheme):
continue
raise exceptions.NotFound(_("Image not found in any configured backend"))
def get_known_schemes_for_multi_store():
"""Returns list of known schemes."""
return location.SCHEME_TO_CLS_BACKEND_MAP.keys()
def get_size_from_uri_and_backend(uri, backend, context=None):
"""Retrieves image size from backend specified by uri."""
loc = location.get_location_from_uri_and_backend(
uri, backend, conf=CONF)
store = get_store_from_store_identifier(backend)
return store.get_size(loc, context=context)