designate/designate/storage/impl_sqlalchemy/migrate_repo/versions/068_add_shard_column.py

102 lines
3.5 KiB
Python

# Copyright 2015 Hewlett-Packard Development Company, L.P.
#
# Author: Endre Karlson <endre.karlson@hp.com>
#
# 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.
from oslo_log import log as logging
from sqlalchemy import Column, MetaData, Table, SmallInteger
from sqlalchemy.sql import select, update
from designate import i18n
LOG = logging.getLogger(__name__)
meta = MetaData()
def _add_shards(engine, table, dst_col, src_col):
dialect = engine.url.get_dialect().name
if dialect.startswith('mysql'):
sql = "UPDATE %s SET %s = CONV(SUBSTR(%s, 1, 3), 16, 10)"
engine.execute(sql % (table.name, dst_col.name, src_col.name))
elif dialect.startswith('postgres'):
sql = "UPDATE %s SET %s = ('x'||lpad(substr(%s::text, 1, 3), 8, '0')"\
")::bit(32)::int"
engine.execute(sql % (table.name, dst_col.name, src_col.name))
else:
rows = select(columns=[table.c.id]).execute().fetchall()
for r in rows:
shard = int(r.id[0:3], 16)
values = {dst_col.name: shard}
update(table).where(table.id == r.id).values(values)
def upgrade(migrate_engine):
meta.bind = migrate_engine
domains_table = Table('domains', meta, autoload=True)
recordsets_table = Table('recordsets', meta, autoload=True)
records_table = Table('records', meta, autoload=True)
domains_shard_col = Column('shard', SmallInteger(), nullable=True)
domains_shard_col.create(domains_table)
recordset_domain_shard_col = Column('domain_shard', SmallInteger(),
nullable=True)
recordset_domain_shard_col.create(recordsets_table)
records_domain_shard_col = Column('domain_shard', SmallInteger(),
nullable=True)
records_domain_shard_col.create(records_table)
def _set_default():
_add_shards(
migrate_engine,
domains_table,
domains_shard_col,
domains_table.c.id)
_add_shards(
migrate_engine,
recordsets_table,
recordset_domain_shard_col,
recordsets_table.c.domain_id)
_add_shards(
migrate_engine,
records_table,
records_domain_shard_col,
records_table.c.domain_id)
def _set_nullable():
domains_table.c.shard.alter(nullable=False)
recordsets_table.c.domain_shard.alter(nullable=False)
records_table.c.domain_shard.alter(nullable=False)
for i in range(0, 5):
try:
_set_default()
_set_nullable()
except Exception as e:
# The population default & enforcement of nullable=False failed,
# try again
msg = i18n._LW(
"Updating migration for sharding failed, retrying.")
LOG.warn(msg)
if i >= 4:
# Raise if we've reached max attempts causing migration to
# fail
raise e
else:
continue
# It was successful, no exception so we break the loop.
break