345 lines
14 KiB
Python
345 lines
14 KiB
Python
# Copyright (c) 2015 Huawei Technologies Co., Ltd.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from oslo_config import cfg
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from oslo_log import log as logging
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import taskflow.engines
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from taskflow.patterns import linear_flow
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from taskflow.types import failure as ft
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from taskflow.utils import misc
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from cinder import exception
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from cinder import flow_utils
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from cinder.i18n import _, _LE, _LI
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from cinder import objects
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from cinder import quota
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from cinder.volume.flows import common as flow_common
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from cinder.volume import utils as volume_utils
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CONF = cfg.CONF
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LOG = logging.getLogger(__name__)
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QUOTAS = quota.QUOTAS
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ACTION = 'snapshot:manage_existing'
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class ExtractSnapshotRefTask(flow_utils.CinderTask):
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"""Extracts snapshot reference for given snapshot id."""
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default_provides = 'snapshot_ref'
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def __init__(self, db):
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super(ExtractSnapshotRefTask, self).__init__(addons=[ACTION])
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self.db = db
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def execute(self, context, snapshot_id):
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# NOTE(wanghao): this will fetch the snapshot from the database, if
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# the snapshot has been deleted before we got here then this should
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# fail.
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#
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# In the future we might want to have a lock on the snapshot_id so that
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# the snapshot can not be deleted while its still being created?
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snapshot_ref = objects.Snapshot.get_by_id(context, snapshot_id)
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LOG.debug("ExtractSnapshotRefTask return"
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" snapshot_ref: %s", snapshot_ref)
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return snapshot_ref
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def revert(self, context, snapshot_id, result, **kwargs):
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if isinstance(result, misc.Failure):
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return
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flow_common.error_out_snapshot(context, self.db, snapshot_id)
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LOG.error(_LE("Snapshot %s: create failed"), snapshot_id)
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class NotifySnapshotActionTask(flow_utils.CinderTask):
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"""Performs a notification about the given snapshot when called.
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Reversion strategy: N/A
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"""
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def __init__(self, db, event_suffix, host):
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super(NotifySnapshotActionTask, self).__init__(addons=[ACTION,
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event_suffix])
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self.db = db
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self.event_suffix = event_suffix
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self.host = host
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def execute(self, context, snapshot_ref):
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snapshot_id = snapshot_ref['id']
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try:
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volume_utils.notify_about_snapshot_usage(context, snapshot_ref,
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self.event_suffix,
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host=self.host)
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except exception.CinderException:
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# If notification sending of snapshot database entry reading fails
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# then we shouldn't error out the whole workflow since this is
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# not always information that must be sent for snapshots to operate
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LOG.exception(_LE("Failed notifying about the snapshot "
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"action %(event)s for snapshot %(snp_id)s."),
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{'event': self.event_suffix,
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'snp_id': snapshot_id})
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class PrepareForQuotaReservationTask(flow_utils.CinderTask):
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"""Gets the snapshot size from the driver."""
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default_provides = set(['size', 'snapshot_properties'])
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def __init__(self, db, driver):
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super(PrepareForQuotaReservationTask, self).__init__(addons=[ACTION])
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self.db = db
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self.driver = driver
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def execute(self, context, snapshot_ref, manage_existing_ref):
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snapshot_id = snapshot_ref['id']
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if not self.driver.initialized:
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driver_name = (self.driver.configuration.
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safe_get('volume_backend_name'))
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LOG.error(_LE("Unable to manage existing snapshot. "
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"Volume driver %s not initialized."), driver_name)
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flow_common.error_out_snapshot(context, self.db, snapshot_id,
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reason=_("Volume driver %s "
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"not initialized.") %
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driver_name)
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raise exception.DriverNotInitialized()
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size = self.driver.manage_existing_snapshot_get_size(
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snapshot=snapshot_ref,
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existing_ref=manage_existing_ref)
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return {'size': size,
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'snapshot_properties': snapshot_ref}
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class QuotaReserveTask(flow_utils.CinderTask):
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"""Reserves a single snapshot with the given size.
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Reversion strategy: rollback the quota reservation.
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Warning Warning: if the process that is running this reserve and commit
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process fails (or is killed before the quota is rolled back or committed
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it does appear like the quota will never be rolled back). This makes
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software upgrades hard (inflight operations will need to be stopped or
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allowed to complete before the upgrade can occur). *In the future* when
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taskflow has persistence built-in this should be easier to correct via
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an automated or manual process.
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"""
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default_provides = set(['reservations'])
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def __init__(self):
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super(QuotaReserveTask, self).__init__(addons=[ACTION])
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def execute(self, context, size, optional_args):
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try:
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if CONF.no_snapshot_gb_quota:
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reserve_opts = {'snapshots': 1}
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else:
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reserve_opts = {'snapshots': 1, 'gigabytes': size}
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reservations = QUOTAS.reserve(context, **reserve_opts)
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return {
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'reservations': reservations,
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}
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except exception.OverQuota as e:
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overs = e.kwargs['overs']
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quotas = e.kwargs['quotas']
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usages = e.kwargs['usages']
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volume_utils.process_reserve_over_quota(context, overs, usages,
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quotas, size)
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def revert(self, context, result, optional_args, **kwargs):
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# We never produced a result and therefore can't destroy anything.
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if isinstance(result, misc.Failure):
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return
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if optional_args['is_quota_committed']:
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# The reservations have already been committed and can not be
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# rolled back at this point.
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return
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# We actually produced an output that we can revert so lets attempt
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# to use said output to rollback the reservation.
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reservations = result['reservations']
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try:
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QUOTAS.rollback(context, reservations)
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except exception.CinderException:
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# We are already reverting, therefore we should silence this
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# exception since a second exception being active will be bad.
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LOG.exception(_LE("Failed rolling back quota for"
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" %s reservations."), reservations)
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class QuotaCommitTask(flow_utils.CinderTask):
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"""Commits the reservation.
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Reversion strategy: N/A (the rollback will be handled by the task that did
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the initial reservation (see: QuotaReserveTask).
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Warning Warning: if the process that is running this reserve and commit
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process fails (or is killed before the quota is rolled back or committed
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it does appear like the quota will never be rolled back). This makes
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software upgrades hard (inflight operations will need to be stopped or
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allowed to complete before the upgrade can occur). *In the future* when
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taskflow has persistence built-in this should be easier to correct via
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an automated or manual process.
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"""
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def __init__(self):
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super(QuotaCommitTask, self).__init__(addons=[ACTION])
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def execute(self, context, reservations, snapshot_properties,
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optional_args):
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QUOTAS.commit(context, reservations)
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# updating is_quota_committed attribute of optional_args dictionary
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optional_args['is_quota_committed'] = True
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return {'snapshot_properties': snapshot_properties}
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def revert(self, context, result, **kwargs):
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# We never produced a result and therefore can't destroy anything.
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if isinstance(result, ft.Failure):
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return
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snapshot = result['snapshot_properties']
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try:
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reserve_opts = {'snapshots': -1,
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'gigabytes': -snapshot['volume_size']}
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reservations = QUOTAS.reserve(context,
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project_id=context.project_id,
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**reserve_opts)
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if reservations:
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QUOTAS.commit(context, reservations,
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project_id=context.project_id)
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except Exception:
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LOG.exception(_LE("Failed to update quota while deleting "
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"snapshots: %s"), snapshot['id'])
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class ManageExistingTask(flow_utils.CinderTask):
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"""Brings an existing snapshot under Cinder management."""
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default_provides = set(['snapshot', 'new_status'])
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def __init__(self, db, driver):
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super(ManageExistingTask, self).__init__(addons=[ACTION])
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self.db = db
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self.driver = driver
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def execute(self, context, snapshot_ref, manage_existing_ref, size):
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model_update = self.driver.manage_existing_snapshot(
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snapshot=snapshot_ref,
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existing_ref=manage_existing_ref)
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if not model_update:
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model_update = {}
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model_update.update({'size': size})
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try:
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snapshot_object = objects.Snapshot.get_by_id(context,
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snapshot_ref['id'])
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snapshot_object.update(model_update)
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snapshot_object.save()
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except exception.CinderException:
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LOG.exception(_LE("Failed updating model of snapshot "
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"%(snapshot_id)s with creation provided model "
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"%(model)s."),
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{'snapshot_id': snapshot_ref['id'],
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'model': model_update})
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raise
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return {'snapshot': snapshot_ref,
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'new_status': 'available'}
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class CreateSnapshotOnFinishTask(NotifySnapshotActionTask):
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"""Perform final snapshot actions.
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When a snapshot is created successfully it is expected that MQ
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notifications and database updates will occur to 'signal' to others that
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the snapshot is now ready for usage. This task does those notifications and
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updates in a reliable manner (not re-raising exceptions if said actions can
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not be triggered).
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Reversion strategy: N/A
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"""
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def __init__(self, db, event_suffix, host):
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super(CreateSnapshotOnFinishTask, self).__init__(db, event_suffix,
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host)
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def execute(self, context, snapshot, new_status):
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LOG.debug("Begin to call CreateSnapshotOnFinishTask execute.")
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snapshot_id = snapshot['id']
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LOG.debug("New status: %s", new_status)
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update = {
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'status': new_status
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}
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try:
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# TODO(harlowja): is it acceptable to only log if this fails??
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# or are there other side-effects that this will cause if the
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# status isn't updated correctly (aka it will likely be stuck in
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# 'building' if this fails)??
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snapshot_object = objects.Snapshot.get_by_id(context,
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snapshot_id)
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snapshot_object.update(update)
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snapshot_object.save()
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# Now use the parent to notify.
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super(CreateSnapshotOnFinishTask, self).execute(context, snapshot)
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except exception.CinderException:
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LOG.exception(_LE("Failed updating snapshot %(snapshot_id)s with "
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"%(update)s."), {'snapshot_id': snapshot_id,
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'update': update})
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# Even if the update fails, the snapshot is ready.
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LOG.info(_LI("Snapshot %s created successfully."), snapshot_id)
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def get_flow(context, db, driver, host, snapshot_id, ref):
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"""Constructs and returns the manager entry point flow."""
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LOG.debug("Input parmeter: context=%(context)s, db=%(db)s,"
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"driver=%(driver)s, host=%(host)s, "
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"snapshot_id=(snapshot_id)s, ref=%(ref)s.",
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{'context': context,
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'db': db,
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'driver': driver,
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'host': host,
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'snapshot_id': snapshot_id,
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'ref': ref}
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)
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flow_name = ACTION.replace(":", "_") + "_manager"
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snapshot_flow = linear_flow.Flow(flow_name)
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# This injects the initial starting flow values into the workflow so that
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# the dependency order of the tasks provides/requires can be correctly
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# determined.
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create_what = {
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'context': context,
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'snapshot_id': snapshot_id,
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'manage_existing_ref': ref,
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'optional_args': {'is_quota_committed': False}
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}
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notify_start_msg = "manage_existing_snapshot.start"
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notify_end_msg = "manage_existing_snapshot.end"
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snapshot_flow.add(ExtractSnapshotRefTask(db),
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NotifySnapshotActionTask(db, notify_start_msg,
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host=host),
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PrepareForQuotaReservationTask(db, driver),
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QuotaReserveTask(),
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ManageExistingTask(db, driver),
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QuotaCommitTask(),
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CreateSnapshotOnFinishTask(db, notify_end_msg,
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host=host))
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LOG.debug("Begin to return taskflow.engines."
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"load(snapshot_flow,store=create_what).")
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# Now load (but do not run) the flow using the provided initial data.
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return taskflow.engines.load(snapshot_flow, store=create_what)
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