glance_store/glance_store/multi_backend.py
Abhishek Kekane da494d4abb Provision to add new config options in sample config file
In Rocky we have added support for multiple backend as a EXPERIMENTAL
feature. However configuration options related to multiple backend
are not generated in sample config file due to some issue. We have
added below 2 new config options for multiple backend.

1. enabled_backneds (added in glance)
2. default_backend (added in glance_store)

Made provision to add option 2 from above to sample config
file.

Change-Id: I63571e4a8f85003e304f16653d60cbd38e6b6bde
Partial-Bug: #1793057
2018-09-18 10:18:54 +00:00

504 lines
18 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 hashlib
import logging
from oslo_config import cfg
from oslo_utils import encodeutils
import six
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 default scheme to use for storing images.
Provide a string value representing the default scheme to use for
storing images. If not set, Glance API service will fail to start.
Related Options:
* enabled_backends
""")),
cfg.IntOpt('store_capabilities_update_min_interval',
default=0,
min=0,
deprecated_for_removal=True,
deprecated_since='Rocky',
deprecated_reason=_("""
This option configures a stub method that has not been implemented
for any existing store drivers. Hence it is non-operational, and
giving it a value does absolutely nothing.
This option is scheduled for removal early in the Stein development
cycle.
"""),
help=_("""
Minimum interval in seconds to execute updating dynamic storage
capabilities based on current backend status.
Provide an integer value representing time in seconds to set the
minimum interval before an update of dynamic storage capabilities
for a storage backend can be attempted. Setting
``store_capabilities_update_min_interval`` does not mean updates
occur periodically based on the set interval. Rather, the update
is performed at the elapse of this interval set, if an operation
of the store is triggered.
By default, this option is set to zero and is disabled. Provide an
integer value greater than zero to enable this option.
NOTE 1: For more information on store capabilities and their updates,
please visit: https://specs.openstack.org/openstack/glance-specs/\
specs/kilo/store-capabilities.html
For more information on setting up a particular store in your
deployment and help with the usage of this feature, please contact
the storage driver maintainers listed here:
https://docs.openstack.org/glance_store/latest/user/drivers.html
NOTE 2: The dynamic store update capability described above is not
implemented by any current store drivers. Thus, this option DOES
NOT DO ANYTHING (and it never has). It is DEPRECATED and scheduled
for removal early in the Stein development cycle.
Possible values:
* Zero
* Positive integer
Related Options:
* None
""")),
]
_STORE_CFG_GROUP = 'glance_store'
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):
LOG.debug("Registering options for group %s", _STORE_CFG_GROUP)
conf.register_opts(_STORE_OPTS, group=_STORE_CFG_GROUP)
driver_opts = _list_driver_opts()
enabled_backends = conf.enabled_backends
for backend in enabled_backends:
for opt_list in driver_opts:
if enabled_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):
enabled_backends = conf.enabled_backends
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):
"""Registers all store modules and all schemes from the given config."""
store_count = 0
scheme_map = {}
for (store_entry, store_instance,
store_identifier) in _load_multi_stores(conf):
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_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
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, six.text_type):
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)