Adds a unique index to quotas

now table quotas not set unique index in project_id and resource,
when set quota concurrently, there may be multiple quota limit
records for the same resource.

Closes-bug: #1893314

Change-Id: I78d2a5accd81a58cf4d6f3be26942a4780f5d43f

neutron/db/migration/alembic_migrations/versions/EXPAND_HEAD

@@ -1 +1 @@
-532aa95457e2
+f010820fc498

neutron/db/migration/alembic_migrations/versions/wallaby/expand/f010820fc498_add_unique_quotas_project_resource.py

@@ -0,0 +1,71 @@
+# Copyright 2020 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
+from neutron_lib import exceptions
+import sqlalchemy as sa
+
+from neutron._i18n import _
+
+
+"""add_unique_quotas_project_resource
+
+Revision ID: f010820fc498
+Revises: 532aa95457e2
+Create Date: 2020-08-28 14:49:50.615623
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = 'f010820fc498'
+down_revision = '532aa95457e2'
+depends_on = ('7d9d8eeec6ad',)
+
+
+quotas = sa.Table(
+    'quotas', sa.MetaData(),
+    sa.Column('project_id', sa.String(255)),
+    sa.Column('resource', sa.String(255)))
+
+
+class DuplicateQuotas(exceptions.Conflict):
+    message = _("Duplicate Quotas are created for resource(s) %(resources)s. "
+                "Database cannot be upgraded. Please, remove all duplicates "
+                "before upgrading the database.")
+
+
+def get_duplicate_quotas(connection):
+    insp = sa.engine.reflection.Inspector.from_engine(connection)
+    if 'quotas' not in insp.get_table_names():
+        return []
+    session = sa.orm.Session(bind=connection.connect())
+    items = (session.query(quotas.c.project_id, quotas.c.resource)
+             .group_by(quotas.c.project_id, quotas.c.resource)
+             .having(sa.func.count() > 1)).all()
+    return items
+
+
+def check_sanity(connection):
+    res = get_duplicate_quotas(connection)
+    if res:
+        resources = ",".join([":".join(r) for r in res])
+        raise DuplicateQuotas(resources=resources)
+
+
+def upgrade():
+    op.create_unique_constraint(
+        op.f('uniq_quotas0project_id0resource'),
+        'quotas',
+        ['project_id', 'resource'])

neutron/db/quota/models.py

@@ -47,6 +47,13 @@ class Quota(model_base.BASEV2, model_base.HasId, model_base.HasProject):
     resource = sa.Column(sa.String(255))
     limit = sa.Column(sa.Integer)
 
+    __table_args__ = (sa.UniqueConstraint(
+        'project_id',
+        'resource',
+        name='uniq_quotas0project_id0resource'),
+        model_base.BASEV2.__table_args__
+    )
+
 
 class QuotaUsage(model_base.BASEV2, model_base.HasProjectPrimaryKeyIndex):
     """Represents the current usage for a given resource."""