Updated constraints on storage state

Given that the storage state is not based only on the storage state
anymore, the unique constraint on the "identifier" column of the
"cloudkitty_storage_states" table has been dropped. A unique constraint
on the "identifier", "scope_key", "collector" and "fetcher" columns
has been added.

Change-Id: Ifbcc47156541cea6f9e1e5cf75923895d3219f6f
Story: 2005699
Task: 31020

cloudkitty/storage_state/alembic/versions/c50ed2c19204_update_storage_state_constraint.py

@@ -0,0 +1,46 @@
+# Copyright 2019 Objectif Libre
+#
+# 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.
+
+"""Update storage state constraint
+
+Revision ID: c50ed2c19204
+Revises: d9d103dd4dcf
+Create Date: 2019-05-15 17:02:56.595274
+
+"""
+from alembic import op
+import six
+
+from cloudkitty.storage_state import models
+
+# revision identifiers, used by Alembic.
+revision = 'c50ed2c19204'
+down_revision = 'd9d103dd4dcf'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    for name, table in six.iteritems(models.Base.metadata.tables):
+        if name == 'cloudkitty_storage_states':
+
+            with op.batch_alter_table(name,
+                                      copy_from=table,
+                                      recreate='always') as batch_op:
+                batch_op.alter_column('identifier')
+                batch_op.create_unique_constraint(
+                    'uq_cloudkitty_storage_states_identifier',
+                    ['identifier', 'scope_key', 'collector', 'fetcher'])
+
+            break

cloudkitty/storage_state/models.py

@@ -18,6 +18,7 @@
 from oslo_db.sqlalchemy import models
 import sqlalchemy
 from sqlalchemy.ext import declarative
+from sqlalchemy import schema
 
 
 Base = declarative.declarative_base()
@@ -25,15 +26,25 @@ Base = declarative.declarative_base()
 
 class IdentifierState(Base, models.ModelBase):
     """Represents the state of a given identifier."""
-    __table_args__ = {'mysql_charset': "utf8",
-                      'mysql_engine': "InnoDB"}
+
+    @declarative.declared_attr
+    def __table_args__(cls):
+        return (
+            schema.UniqueConstraint(
+                'identifier',
+                'scope_key',
+                'collector',
+                'fetcher',
+                name='uq_cloudkitty_storage_states_identifier'),
+        )
+
     __tablename__ = 'cloudkitty_storage_states'
 
     id = sqlalchemy.Column(sqlalchemy.Integer,
                            primary_key=True)
     identifier = sqlalchemy.Column(sqlalchemy.String(256),
                                    nullable=False,
-                                   unique=True)
+                                   unique=False)
     scope_key = sqlalchemy.Column(sqlalchemy.String(40),
                                   nullable=True,
                                   unique=False)