Drop the (unused) domain table

The Mitaka release removed all code that referenced the domain
table (with domains being stored instead as projects). However,
the physical domain table was not removed.

This patch removes the table. Such an action triggers our
detection of banned operations to ensure rolling upgrades are
possible. In this case, since all the code that referenced
this table was already removed in the previous release, this
is still a safe operation - so this migation is added to the
exception list in the test for banned operations.

Change-Id: I11bb23809e28b7fb0499cf79d261aa54f094b367

keystone/common/sql/migrate_repo/versions/102_drop_domain_table.py

@@ -0,0 +1,21 @@
+# 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.
+
+import sqlalchemy as sql
+
+
+def upgrade(migrate_engine):
+    meta = sql.MetaData()
+    meta.bind = migrate_engine
+
+    domain_table = sql.Table('domain', meta, autoload=True)
+    domain_table.drop()

keystone/resource/backends/sql.py

@@ -219,16 +219,6 @@ class Resource(base.ResourceDriverV9):
             query.delete(synchronize_session=False)
 
 
-class Domain(sql.ModelBase, sql.DictBase):
-    __tablename__ = 'domain'
-    attributes = ['id', 'name', 'enabled']
-    id = sql.Column(sql.String(64), primary_key=True)
-    name = sql.Column(sql.String(64), nullable=False)
-    enabled = sql.Column(sql.Boolean, default=True, nullable=False)
-    extra = sql.Column(sql.JsonBlob())
-    __table_args__ = (sql.UniqueConstraint('name'),)
-
-
 class Project(sql.ModelBase, sql.DictBase):
     # NOTE(henry-nash): From the manager and above perspective, the domain_id
     # is nullable.  However, to ensure uniqueness in multi-process

keystone/tests/unit/test_backend_sql.py

@@ -165,13 +165,6 @@ class SqlModels(SqlTests):
                 ('extra', sql.JsonBlob, None))
         self.assertExpectedSchema('group', cols)
 
-    def test_domain_model(self):
-        cols = (('id', sql.String, 64),
-                ('name', sql.String, 64),
-                ('enabled', sql.Boolean, True),
-                ('extra', sql.JsonBlob, None))
-        self.assertExpectedSchema('domain', cols)
-
     def test_project_model(self):
         cols = (('id', sql.String, 64),
                 ('name', sql.String, 64),

keystone/tests/unit/test_sql_banned_operations.py

@@ -126,7 +126,15 @@ class KeystoneMigrationsCheckers(test_migrations.WalkVersionsMixin):
         # http://docs.openstack.org/developer/keystone/developing.html#online-migration
 
         exceptions = [
-            # NOTE(xek): Reviewers: DO NOT ALLOW THINGS TO BE ADDED HERE
+            # NOTE(xek): Reviewers: DO NOT ALLOW THINGS TO BE ADDED HERE UNLESS
+            # JUSTIFICATION CAN BE PROVIDED AS TO WHY THIS WILL NOT CAUSE
+            # PROBLEMS FOR ROLLING UPGRADES.
+
+            # Migration 102 drops the domain table in the Newton release. All
+            # code that referenced the domain table was removed in the Mitaka
+            # release, hence this migration will not cause problems when
+            # running a mixture of Mitaka and Newton versions of keystone.
+            102
         ]
 
         # NOTE(xek): We start requiring things be additive in Newton, so

keystone/tests/unit/test_sql_upgrade.py

@@ -1156,6 +1156,12 @@ class SqlUpgradeTests(SqlMigrateBase):
             self.assertFalse(self.does_constraint_exist('role',
                                                         'ixu_role_name'))
 
+    def test_drop_domain_table(self):
+        self.upgrade(101)
+        self.assertTableExists('domain')
+        self.upgrade(102)
+        self.assertTableDoesNotExist('domain')
+
 
 class MySQLOpportunisticUpgradeTestCase(SqlUpgradeTests):
     FIXTURE = test_base.MySQLOpportunisticFixture