Add shard and domain_shard to tables

This change adds shard to domains and domain_shard to records / recordsets as a
prerequisite for the designate-zm service.

Change-Id: Ieb6eee611bf7b87fef79e3a108294bc0769cd685

designate/objects/domain.py

@@ -24,6 +24,13 @@ from designate.objects.domain_attribute import DomainAttributeList
 class Domain(base.DictObjectMixin, base.SoftDeleteObjectMixin,
              base.PersistentObjectMixin, base.DesignateObject):
     FIELDS = {
+        'shard': {
+            'schema': {
+                'type': 'integer',
+                'minimum': 0,
+                'maximum': 4095
+            }
+        },
         'tenant_id': {
             'schema': {
                 'type': 'string',

designate/objects/record.py

@@ -20,6 +20,13 @@ class Record(base.DictObjectMixin, base.PersistentObjectMixin,
     # TODO(kiall): `hash` is an implementation detail of our SQLA driver,
     #              so we should remove it.
     FIELDS = {
+        'shard': {
+            'schema': {
+                'type': 'integer',
+                'minimum': 0,
+                'maximum': 4095
+            }
+        },
         'data': {},
         'domain_id': {
             'schema': {

designate/objects/recordset.py

@@ -68,6 +68,13 @@ class RecordSet(base.DictObjectMixin, base.PersistentObjectMixin,
         return status
 
     FIELDS = {
+        'shard': {
+            'schema': {
+                'type': 'integer',
+                'minimum': 0,
+                'maximum': 4095
+            }
+        },
         'tenant_id': {
             'schema': {
                 'type': 'string',

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

@@ -0,0 +1,101 @@
+# 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

designate/storage/impl_sqlalchemy/tables.py

@@ -13,9 +13,9 @@
 # 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 sqlalchemy import (Table, MetaData, Column, String, Text, Integer, CHAR,
-                        DateTime, Enum, Boolean, Unicode, UniqueConstraint,
-                        ForeignKeyConstraint)
+from sqlalchemy import (Table, MetaData, Column, String, Text, Integer,
+                        SmallInteger, CHAR, DateTime, Enum, Boolean, Unicode,
+                        UniqueConstraint, ForeignKeyConstraint)
 
 from oslo_config import cfg
 from oslo_utils import timeutils
@@ -44,6 +44,11 @@ ZONE_TASK_TYPES = ['IMPORT']
 
 metadata = MetaData()
 
+
+def default_shard(context, id_col):
+    return int(context.current_parameters[id_col][0:3], 16)
+
+
 quotas = Table('quotas', metadata,
     Column('id', UUID, default=utils.generate_uuid, primary_key=True),
     Column('version', Integer(), default=1, nullable=False),
@@ -80,6 +85,8 @@ domains = Table('domains', metadata,
     Column('deleted', CHAR(32), nullable=False, default='0',
            server_default='0'),
     Column('deleted_at', DateTime, nullable=True, default=None),
+    Column('shard', SmallInteger(), nullable=False,
+           default=lambda ctxt: default_shard(ctxt, 'id')),
 
     Column('tenant_id', String(36), default=None, nullable=True),
     Column('name', String(255), nullable=False),
@@ -134,6 +141,8 @@ recordsets = Table('recordsets', metadata,
     Column('version', Integer(), default=1, nullable=False),
     Column('created_at', DateTime, default=lambda: timeutils.utcnow()),
     Column('updated_at', DateTime, onupdate=lambda: timeutils.utcnow()),
+    Column('domain_shard', SmallInteger(), nullable=False,
+           default=lambda ctxt: default_shard(ctxt, 'domain_id')),
 
     Column('tenant_id', String(36), default=None, nullable=True),
     Column('domain_id', UUID, nullable=False),
@@ -155,6 +164,8 @@ records = Table('records', metadata,
     Column('version', Integer(), default=1, nullable=False),
     Column('created_at', DateTime, default=lambda: timeutils.utcnow()),
     Column('updated_at', DateTime, onupdate=lambda: timeutils.utcnow()),
+    Column('domain_shard', SmallInteger(), nullable=False,
+           default=lambda ctxt: default_shard(ctxt, 'domain_id')),
 
     Column('tenant_id', String(36), default=None, nullable=True),
     Column('domain_id', UUID, nullable=False),