77e4958f25
Before there was no way to upgrade to a specific revision, because the revision passed to the manager was passed to all the plugins, some of which failed to process it. Add a new method to every plugin `has_revision`, which returns whether the plugin has the revision. Use it in upgrade and downgrade. Change-Id: I89b02d7ad479da6bff3c492c88edfee9c19abc22 Closes-Bug: 1474067
108 lines
4.0 KiB
Python
108 lines
4.0 KiB
Python
# 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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import sqlalchemy
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from stevedore import enabled
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from oslo_db import exception
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MIGRATION_NAMESPACE = 'oslo.db.migration'
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def check_plugin_enabled(ext):
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"""Used for EnabledExtensionManager."""
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return ext.obj.enabled
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class MigrationManager(object):
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def __init__(self, migration_config, engine=None):
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if engine is None:
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if migration_config.get('db_url'):
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engine = sqlalchemy.create_engine(
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migration_config['db_url'],
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poolclass=sqlalchemy.pool.NullPool,
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)
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else:
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raise ValueError('Either database url or engine'
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' must be provided.')
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self._manager = enabled.EnabledExtensionManager(
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MIGRATION_NAMESPACE,
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check_plugin_enabled,
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invoke_args=(engine, migration_config),
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invoke_on_load=True
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)
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if not self._plugins:
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raise ValueError('There must be at least one plugin active.')
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@property
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def _plugins(self):
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return sorted(ext.obj for ext in self._manager.extensions)
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def upgrade(self, revision):
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"""Upgrade database with all available backends."""
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# a revision exists only in a single plugin. Until we reached it, we
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# should upgrade to the plugins' heads.
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# revision=None is a special case meaning latest revision.
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rev_in_plugins = [p.has_revision(revision) for p in self._plugins]
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if not any(rev_in_plugins) and revision is not None:
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raise exception.DbMigrationError('Revision does not exist')
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results = []
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for plugin, has_revision in zip(self._plugins, rev_in_plugins):
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if not has_revision or revision is None:
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results.append(plugin.upgrade(None))
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else:
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results.append(plugin.upgrade(revision))
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break
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return results
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def downgrade(self, revision):
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"""Downgrade database with available backends."""
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# a revision exists only in a single plugin. Until we reached it, we
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# should upgrade to the plugins' first revision.
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# revision=None is a special case meaning initial revision.
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rev_in_plugins = [p.has_revision(revision) for p in self._plugins]
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if not any(rev_in_plugins) and revision is not None:
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raise exception.DbMigrationError('Revision does not exist')
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# downgrading should be performed in reversed order
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results = []
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for plugin, has_revision in zip(reversed(self._plugins),
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reversed(rev_in_plugins)):
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if not has_revision or revision is None:
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results.append(plugin.downgrade(None))
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else:
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results.append(plugin.downgrade(revision))
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break
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return results
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def version(self):
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"""Return last version of db."""
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last = None
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for plugin in self._plugins:
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version = plugin.version()
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if version is not None:
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last = version
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return last
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def revision(self, message, autogenerate):
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"""Generate template or autogenerated revision."""
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# revision should be done only by last plugin
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return self._plugins[-1].revision(message, autogenerate)
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def stamp(self, revision):
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"""Create stamp for a given revision."""
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return self._plugins[-1].stamp(revision)
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