[OVN] Add DB tables for OVN backend

Added "ovn_revision_numbers" and "ovn_hash_ring" DB tables and models.

Change-Id: I07237946af698816a4229efec16de8f8f8addee9
Partially-Implements: blueprint neutron-ovn-merge

neutron/db/migration/alembic_migrations/versions/EXPAND_HEAD

@@ -1 +1 @@
-86274d77933e
+f4b9654dd40c

neutron/db/migration/alembic_migrations/versions/ussuri/expand/f4b9654dd40c_ovn_backend.py

@@ -0,0 +1,74 @@
+# Copyright 2019 OpenStack Foundation
+#
+#    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 alembic import op
+import sqlalchemy as sa
+from sqlalchemy.engine import reflection
+
+
+"""ovn backend
+
+Revision ID: f4b9654dd40c
+Revises: 86274d77933e
+Create Date: 2019-11-25 13:09:31.367837
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = 'f4b9654dd40c'
+down_revision = '86274d77933e'
+
+OVN_REVISION_NUMBERS = 'ovn_revision_numbers'
+OVN_HASH_RING = 'ovn_hash_ring'
+
+
+def upgrade():
+    inspector = reflection.Inspector.from_engine(op.get_bind())
+    table_names = inspector.get_table_names()
+    if OVN_REVISION_NUMBERS in table_names and OVN_HASH_RING in table_names:
+        op.alter_column(OVN_REVISION_NUMBERS, 'revision_number',
+                        nullable=False, server_default='0',
+                        existing_type=sa.BIGINT(), existing_nullable=False)
+        return
+
+    op.create_table(
+        OVN_REVISION_NUMBERS,
+        sa.Column('standard_attr_id', sa.BigInteger, nullable=True),
+        sa.Column('resource_uuid', sa.String(36), nullable=False, index=True),
+        sa.Column('resource_type', sa.String(36), nullable=False, index=True),
+        sa.Column('revision_number', sa.BigInteger, nullable=False,
+                  server_default='0'),
+        sa.Column('created_at', sa.DateTime, nullable=False,
+                  default=sa.func.now()),
+        sa.Column('updated_at', sa.TIMESTAMP, default=sa.func.now(),
+                  onupdate=sa.func.now(), nullable=True),
+        sa.ForeignKeyConstraint(
+            ['standard_attr_id'], ['standardattributes.id'],
+            ondelete='SET NULL'),
+        sa.PrimaryKeyConstraint('resource_uuid', 'resource_type')
+    )
+
+    op.create_table(
+        OVN_HASH_RING,
+        sa.Column('node_uuid', sa.String(36), nullable=False, index=True),
+        sa.Column('group_name', sa.String(length=256), nullable=False,
+                  index=True),
+        sa.Column('hostname', sa.String(length=256), nullable=False),
+        sa.Column('created_at', sa.DateTime, nullable=False,
+                  default=sa.func.now()),
+        sa.Column('updated_at', sa.DateTime, nullable=False,
+                  default=sa.func.now()),
+        sa.PrimaryKeyConstraint('node_uuid', 'group_name'),
+    )

neutron/db/models/ovn.py

@@ -0,0 +1,63 @@
+# Copyright 2019 Red Hat, Inc.
+# All Rights Reserved.
+#
+#    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 neutron_lib.db import model_base
+import sqlalchemy as sa
+from sqlalchemy.dialects import sqlite
+
+
+class OVNRevisionNumbers(model_base.BASEV2):
+    __tablename__ = 'ovn_revision_numbers'
+
+    standard_attr_id = sa.Column(
+        sa.BigInteger().with_variant(sa.Integer(), 'sqlite'),
+        sa.ForeignKey('standardattributes.id', ondelete='SET NULL'),
+        nullable=True)
+    resource_uuid = sa.Column(sa.String(36), nullable=False, index=True)
+    resource_type = sa.Column(sa.String(36), nullable=False, index=True)
+    revision_number = sa.Column(
+        sa.BigInteger().with_variant(sa.Integer(), 'sqlite'),
+        server_default='0', default=0, nullable=False)
+    created_at = sa.Column(
+        sa.DateTime().with_variant(
+            sqlite.DATETIME(truncate_microseconds=True), 'sqlite'),
+        default=sa.func.now(), nullable=False)
+    updated_at = sa.Column(sa.TIMESTAMP, default=sa.func.now(),
+                           onupdate=sa.func.now(), nullable=True)
+
+    __table_args__ = (
+        sa.PrimaryKeyConstraint(
+            resource_uuid, resource_type,
+            name='ovn_revision_numbers0resource_uuid0resource_type'),
+        model_base.BASEV2.__table_args__
+    )
+
+
+class OVNHashRing(model_base.BASEV2):
+    __tablename__ = 'ovn_hash_ring'
+
+    node_uuid = sa.Column(sa.String(36), nullable=False, index=True)
+    group_name = sa.Column(sa.String(256), nullable=False, index=True)
+    hostname = sa.Column(sa.String(256), nullable=False)
+    created_at = sa.Column(sa.DateTime(), default=sa.func.now(),
+                           nullable=False)
+    updated_at = sa.Column(sa.DateTime(), default=sa.func.now(),
+                           nullable=False)
+    __table_args__ = (
+        sa.PrimaryKeyConstraint(
+            node_uuid, group_name,
+            name='ovn_hash_ring0node_uuid0group_name'),
+        model_base.BASEV2.__table_args__
+    )