[placement] Add Traits related table to the api database

This patch adds DB table `traits` and `resource_provider_traits` into
the api database.

The traits table is used to represent the trait. The resource_provider_traits
table is used to represent the relationship between trait and resource provider.

Part of implementation blueprint shared-resources-pike

Change-Id: I5c34bdd1423beab53cc4af45e016d9a9bba5ffda

nova/db/sqlalchemy/api_migrations/migrate_repo/versions/041_resource_provider_traits.py

@@ -0,0 +1,66 @@
+#    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.
+"""Database migrations for traits"""
+
+from migrate.changeset.constraint import ForeignKeyConstraint
+from migrate import UniqueConstraint
+from sqlalchemy import Column
+from sqlalchemy import DateTime
+from sqlalchemy import ForeignKey
+from sqlalchemy import Index
+from sqlalchemy import Integer
+from sqlalchemy import MetaData
+from sqlalchemy import Table
+from sqlalchemy import Unicode
+
+
+def upgrade(migrate_engine):
+    meta = MetaData()
+    meta.bind = migrate_engine
+
+    if migrate_engine.name == 'mysql':
+        nameargs = {'collation': 'utf8_bin'}
+    else:
+        nameargs = {}
+
+    resource_providers = Table('resource_providers', meta, autoload=True)
+
+    traits = Table(
+        'traits', meta,
+        Column('created_at', DateTime),
+        Column('updated_at', DateTime),
+        Column('id', Integer, primary_key=True, nullable=False,
+               autoincrement=True),
+        Column('name', Unicode(255, **nameargs), nullable=False),
+        UniqueConstraint('name', name='uniq_traits0name'),
+        mysql_engine='InnoDB',
+        mysql_charset='latin1'
+    )
+
+    resource_provider_traits = Table(
+        'resource_provider_traits', meta,
+        Column('created_at', DateTime),
+        Column('updated_at', DateTime),
+        Column('trait_id', Integer, ForeignKey('traits.id'), primary_key=True,
+               nullable=False),
+        Column('resource_provider_id', Integer, primary_key=True,
+               nullable=False),
+        Index('resource_provider_traits_resource_provider_trait_idx',
+              'resource_provider_id', 'trait_id'),
+        ForeignKeyConstraint(columns=['resource_provider_id'],
+                             refcolumns=[resource_providers.c.id]),
+        mysql_engine='InnoDB',
+        mysql_charset='latin1'
+    )
+
+    for table in [traits, resource_provider_traits]:
+        table.create(checkfirst=True)

nova/db/sqlalchemy/api_models.py

@@ -553,3 +553,32 @@ class Reservation(API_BASE):
         "QuotaUsage",
         foreign_keys=usage_id,
         primaryjoin='Reservation.usage_id == QuotaUsage.id')
+
+
+class Trait(API_BASE):
+    """Represents a trait."""
+
+    __tablename__ = "traits"
+    __table_args__ = (
+        schema.UniqueConstraint('name', name='uniq_traits0name'),
+    )
+
+    id = Column(Integer, primary_key=True, nullable=False, autoincrement=True)
+    name = Column(Unicode(255), nullable=False)
+
+
+class ResourceProviderTraits(API_BASE):
+    """Represents the relationship between traits and resource provider"""
+
+    __tablename__ = "resource_provider_traits"
+    __table_args__ = (
+        Index('resource_provider_traits_resource_provider_trait_idx',
+              'resource_provider_id', 'trait_id'),
+    )
+
+    trait_id = Column(Integer, ForeignKey('traits.id'), primary_key=True,
+                      nullable=False)
+    resource_provider_id = Column(Integer,
+                                  ForeignKey('resource_providers.id'),
+                                  primary_key=True,
+                                  nullable=False)

nova/tests/functional/db/api/test_migrations.py

@@ -582,6 +582,29 @@ class NovaAPIMigrationsWalk(test_migrations.WalkVersionsMixin):
         for column in ['created_at', 'updated_at', 'id', 'uuid']:
             self.assertColumnExists(engine, 'placement_aggregates', column)
 
+    def _check_041(self, engine, data):
+        self.assertColumnExists(engine, 'traits', 'id')
+        self.assertUniqueConstraintExists(engine, 'traits', ['name'])
+
+        self.assertColumnExists(engine, 'resource_provider_traits', 'trait_id')
+        self.assertColumnExists(engine, 'resource_provider_traits',
+                                'resource_provider_id')
+        self.assertIndexExists(
+            engine, 'resource_provider_traits',
+            'resource_provider_traits_resource_provider_trait_idx')
+
+        inspector = reflection.Inspector.from_engine(engine)
+        self.assertEqual(
+            2, len(inspector.get_foreign_keys('resource_provider_traits')))
+        for fk in inspector.get_foreign_keys('resource_provider_traits'):
+            if 'traits' == fk['referred_table']:
+                self.assertEqual(['id'], fk['referred_columns'])
+                self.assertEqual(['trait_id'], fk['constrained_columns'])
+            elif 'resource_providers' == fk['referred_table']:
+                self.assertEqual(['id'], fk['referred_columns'])
+                self.assertEqual(['resource_provider_id'],
+                                 fk['constrained_columns'])
+
 
 class TestNovaAPIMigrationsWalkSQLite(NovaAPIMigrationsWalk,
                                       test_base.DbTestCase,