Drop support database downgrades

Remove downgrade from migrations and tests

Related cross-project spec:
http://specs.openstack.org/openstack/openstack-specs/specs/no-downward-sql-migration.html

Change-Id: Ib286cfdc6df19506e33194337ce8acb58991a139
Closes-bug: #1434103

sahara/db/migration/alembic_migrations/README.md

@@ -16,7 +16,7 @@ under the License.
 
 The migrations in `alembic_migrations/versions` contain the changes needed to migrate
 between Sahara database revisions. A migration occurs by executing a script that
-details the changes needed to upgrade or downgrade the database. The migration scripts
+details the changes needed to upgrade the database. The migration scripts
 are ordered so that multiple scripts can run sequentially. The scripts are executed by
 Sahara's migration wrapper which uses the Alembic library to manage the migration. Sahara
 supports migration from Icehouse or later.
@@ -46,11 +46,6 @@ Upgrade the database incrementally:
 $ sahara-db-manage --config-file /path/to/sahara.conf upgrade --delta <# of revs>
 ```
 
-Downgrade the database by a certain number of revisions:
-```
-$ sahara-db-manage --config-file /path/to/sahara.conf downgrade --delta <# of revs>
-```
-
 Create new revision:
 ```
 $ sahara-db-manage --config-file /path/to/sahara.conf revision -m "description of revision" --autogenerate

sahara/db/migration/alembic_migrations/script.py.mako

@@ -32,7 +32,3 @@ ${imports if imports else ""}
 
 def upgrade():
     ${upgrades if upgrades else "pass"}
-
-
-def downgrade():
-    ${downgrades if downgrades else "pass"}

sahara/db/migration/alembic_migrations/versions/001_icehouse.py

@@ -332,19 +332,3 @@ def upgrade():
                     sa.UniqueConstraint('instance_id', 'node_group_id'),
                     mysql_engine=MYSQL_ENGINE,
                     mysql_charset=MYSQL_CHARSET)
-
-
-def downgrade():
-    op.drop_table('instances')
-    op.drop_table('node_groups')
-    op.drop_table('job_executions')
-    op.drop_table('mains_association')
-    op.drop_table('templates_relations')
-    op.drop_table('clusters')
-    op.drop_table('libs_association')
-    op.drop_table('data_sources')
-    op.drop_table('job_binaries')
-    op.drop_table('job_binary_internal')
-    op.drop_table('cluster_templates')
-    op.drop_table('node_group_templates')
-    op.drop_table('jobs')

sahara/db/migration/alembic_migrations/versions/002_placeholder.py

@@ -28,7 +28,3 @@ down_revision = '001'
 
 def upgrade():
     pass
-
-
-def downgrade():
-    pass

sahara/db/migration/alembic_migrations/versions/003_placeholder.py

@@ -28,7 +28,3 @@ down_revision = '002'
 
 def upgrade():
     pass
-
-
-def downgrade():
-    pass

sahara/db/migration/alembic_migrations/versions/004_placeholder.py

@@ -28,7 +28,3 @@ down_revision = '003'
 
 def upgrade():
     pass
-
-
-def downgrade():
-    pass

sahara/db/migration/alembic_migrations/versions/005_placeholder.py

@@ -28,7 +28,3 @@ down_revision = '004'
 
 def upgrade():
     pass
-
-
-def downgrade():
-    pass

sahara/db/migration/alembic_migrations/versions/006_placeholder.py

@@ -28,7 +28,3 @@ down_revision = '005'
 
 def upgrade():
     pass
-
-
-def downgrade():
-    pass

sahara/db/migration/alembic_migrations/versions/007_increase_status_description_size.py

@@ -26,7 +26,6 @@ revision = '007'
 down_revision = '006'
 
 from alembic import op
-import sqlalchemy as sa
 
 from sahara.db.sqlalchemy import types as st
 
@@ -35,9 +34,3 @@ def upgrade():
     op.alter_column('clusters', 'status_description',
                     type_=st.LongText(), existing_nullable=True,
                     existing_server_default=None)
-
-
-def downgrade():
-    op.alter_column('clusters', 'status_description',
-                    type_=sa.String(length=200), existing_nullable=True,
-                    existing_server_default=None)

sahara/db/migration/alembic_migrations/versions/008_security_groups.py

@@ -38,9 +38,3 @@ def upgrade():
                   sa.Column('security_groups', st.JsonEncoded()))
     op.add_column('templates_relations',
                   sa.Column('security_groups', st.JsonEncoded()))
-
-
-def downgrade():
-    op.drop_column('node_group_templates', 'security_groups')
-    op.drop_column('node_groups', 'security_groups')
-    op.drop_column('templates_relations', 'security_groups')

sahara/db/migration/alembic_migrations/versions/009_rollback_info.py

@@ -34,7 +34,3 @@ from sahara.db.sqlalchemy import types as st
 def upgrade():
     op.add_column('clusters',
                   sa.Column('rollback_info', st.JsonEncoded()))
-
-
-def downgrade():
-    op.drop_column('clusters', 'rollback_info')

sahara/db/migration/alembic_migrations/versions/010_auto_security_groups.py

@@ -40,10 +40,3 @@ def upgrade():
                   sa.Column('auto_security_group', sa.Boolean()))
     op.add_column('node_groups',
                   sa.Column('open_ports', st.JsonEncoded()))
-
-
-def downgrade():
-    op.drop_column('node_group_templates', 'auto_security_group')
-    op.drop_column('node_groups', 'auto_security_group')
-    op.drop_column('templates_relations', 'auto_security_group')
-    op.drop_column('node_groups', 'open_ports')

sahara/db/migration/alembic_migrations/versions/011_sahara_info.py

@@ -34,7 +34,3 @@ from sahara.db.sqlalchemy import types as st
 def upgrade():
     op.add_column('clusters',
                   sa.Column('sahara_info', st.JsonEncoded()))
-
-
-def downgrade():
-    op.drop_column('clusters', 'sahara_info')

sahara/db/migration/alembic_migrations/versions/012_availability_zone.py

@@ -37,9 +37,3 @@ def upgrade():
                   sa.Column('availability_zone', sa.String(length=255)))
     op.add_column('templates_relations',
                   sa.Column('availability_zone', sa.String(length=255)))
-
-
-def downgrade():
-    op.drop_column('node_group_templates', 'availability_zone')
-    op.drop_column('node_groups', 'availability_zone')
-    op.drop_column('templates_relations', 'availability_zone')

sahara/db/migration/alembic_migrations/versions/013_volumes_availability_zone.py

@@ -38,9 +38,3 @@ def upgrade():
                                            sa.String(length=255)))
     op.add_column('templates_relations', sa.Column('volumes_availability_zone',
                                                    sa.String(length=255)))
-
-
-def downgrade():
-    op.drop_column('node_group_templates', 'volumes_availability_zone')
-    op.drop_column('node_groups', 'volumes_availability_zone')
-    op.drop_column('templates_relations', 'volumes_availability_zone')

sahara/db/migration/alembic_migrations/versions/014_add_volume_type.py

@@ -39,9 +39,3 @@ def upgrade():
     op.add_column('templates_relations',
                   sa.Column('volume_type', sa.String(length=255),
                             nullable=True))
-
-
-def downgrade():
-    op.drop_column('templates_relations', 'volume_type')
-    op.drop_column('node_groups', 'volume_type')
-    op.drop_column('node_group_templates', 'volume_type')

sahara/db/migration/alembic_migrations/versions/015_add_events_objects.py

@@ -91,8 +91,3 @@ def upgrade():
                     sa.UniqueConstraint('id', 'step_id'),
                     mysql_engine=MYSQL_ENGINE,
                     mysql_charset=MYSQL_CHARSET)
-
-
-def downgrade():
-    op.drop_table('cluster_events')
-    op.drop_table('cluster_provision_steps')

sahara/db/migration/alembic_migrations/versions/016_is_proxy_gateway.py

@@ -36,9 +36,3 @@ def upgrade():
                   sa.Column('is_proxy_gateway', sa.Boolean()))
     op.add_column('templates_relations',
                   sa.Column('is_proxy_gateway', sa.Boolean()))
-
-
-def downgrade():
-    op.drop_column('templates_relations', 'is_proxy_gateway')
-    op.drop_column('node_groups', 'is_proxy_gateway')
-    op.drop_column('node_group_templates', 'is_proxy_gateway')

sahara/db/migration/alembic_migrations/versions/017_drop_progress.py

@@ -26,13 +26,7 @@ revision = '017'
 down_revision = '016'
 
 from alembic import op
-import sqlalchemy as sa
 
 
 def upgrade():
     op.drop_column('job_executions', 'progress')
-
-
-def downgrade():
-    op.add_column('job_executions',
-                  sa.Column('progress', sa.FLOAT(), nullable=True))

sahara/db/migration/alembic_migrations/versions/018_volume_local_to_instance.py

@@ -36,9 +36,3 @@ def upgrade():
                   sa.Column('volume_local_to_instance', sa.Boolean()))
     op.add_column('templates_relations',
                   sa.Column('volume_local_to_instance', sa.Boolean()))
-
-
-def downgrade():
-    op.drop_column('node_group_templates', 'volume_local_to_instance')
-    op.drop_column('node_groups', 'volume_local_to_instance')
-    op.drop_column('templates_relations', 'volume_local_to_instance')

sahara/db/migration/alembic_migrations/versions/019_is_default_for_templates.py

@@ -34,8 +34,3 @@ def upgrade():
                   sa.Column('is_default', sa.Boolean(), nullable=True))
     op.add_column('node_group_templates',
                   sa.Column('is_default', sa.Boolean(), nullable=True))
-
-
-def downgrade():
-    op.drop_column('node_group_templates', 'is_default')
-    op.drop_column('cluster_templates', 'is_default')

sahara/db/migration/alembic_migrations/versions/020_remove_redandunt_progress_ops.py

@@ -26,19 +26,9 @@ revision = '020'
 down_revision = '019'
 
 from alembic import op
-import sqlalchemy as sa
 
 
 def upgrade():
     op.drop_column('cluster_provision_steps', 'completed_at')
     op.drop_column('cluster_provision_steps', 'completed')
     op.drop_column('cluster_provision_steps', 'started_at')
-
-
-def downgrade():
-    op.add_column('cluster_provision_steps',
-                  sa.Column('completed', sa.Integer(), nullable=True))
-    op.add_column('cluster_provision_steps',
-                  sa.Column('started_at', sa.DateTime(), nullable=True))
-    op.add_column('cluster_provision_steps',
-                  sa.Column('completed_at', sa.DateTime(), nullable=True))

sahara/db/migration/cli.py

@@ -70,7 +70,7 @@ def add_command_parsers(subparsers):
     parser = subparsers.add_parser('check_migration')
     parser.set_defaults(func=do_check_migration)
 
-    for name in ['upgrade', 'downgrade']:
+    for name in ['upgrade']:
         parser = subparsers.add_parser(name)
         parser.add_argument('--delta', type=int)
         parser.add_argument('--sql', action='store_true')

sahara/tests/unit/db/migration/test_db_manage_cli.py

@@ -65,19 +65,7 @@ class TestCli(testtools.TestCase):
          dict(argv=['prog', 'upgrade', '--delta', '3'],
               func_name='upgrade',
               exp_args=('+3',),
-              exp_kwargs={'sql': False})),
+              exp_kwargs={'sql': False}))
-
-        ('downgrade-sql',
-         dict(argv=['prog', 'downgrade', '--sql', 'folsom'],
-              func_name='downgrade',
-              exp_args=('folsom',),
-              exp_kwargs={'sql': True})),
-
-        ('downgrade-delta',
-         dict(argv=['prog', 'downgrade', '--delta', '2'],
-              func_name='downgrade',
-              exp_args=('-2',),
-              exp_kwargs={'sql': False})),
     ]
 
     def setUp(self):

sahara/tests/unit/db/migration/test_migrations.py

@@ -39,9 +39,6 @@ from sahara.tests.unit.db.migration import test_migrations_base as base
 
 class SaharaMigrationsCheckers(object):
 
-    snake_walk = True
-    downgrade = True
-
     def assertColumnExists(self, engine, table, column):
         t = db_utils.get_table(engine, table)
         self.assertIn(column, t.c)
@@ -76,7 +73,7 @@ class SaharaMigrationsCheckers(object):
         self.assertEqual(sorted(members), sorted(index_columns))
 
     def test_walk_versions(self):
-        self.walk_versions(self.engine, self.snake_walk, self.downgrade)
+        self.walk_versions(self.engine)
 
     def _pre_upgrade_001(self, engine):
         # Anything returned from this method will be

sahara/tests/unit/db/migration/test_migrations_base.py

@@ -78,54 +78,33 @@ class BaseWalkMigrationTestCase(object):
         sa.cleanup()
         return res
 
-    def _up_and_down_versions(self):
+    def _get_versions(self):
-        """Stores a tuple of versions.
+        """Stores a list of versions.
 
         Since alembic version has a random algorithm of generation
         (SA-migrate has an ordered autoincrement naming) we should store
-        a tuple of versions (version for upgrade and version for downgrade)
+        a list of versions (version for upgrade)
-        for successful testing of migrations in up>down>up mode.
+        for successful testing of migrations in up mode.
         """
 
         env = alembic_script.ScriptDirectory.from_config(self.ALEMBIC_CONFIG)
         versions = []
         for rev in env.walk_revisions():
-            versions.append((rev.revision, rev.down_revision or '-1'))
+            versions.append(rev.revision)
 
         versions.reverse()
         return versions
 
-    def walk_versions(self, engine=None, snake_walk=False, downgrade=True):
+    def walk_versions(self, engine=None):
         # Determine latest version script from the repo, then
         # upgrade from 1 through to the latest, with no data
         # in the databases. This just checks that the schema itself
         # upgrades successfully.
 
         self._configure(engine)
-        up_and_down_versions = self._up_and_down_versions()
+        versions = self._get_versions()
-        for ver_up, ver_down in up_and_down_versions:
+        for ver in versions:
-            # upgrade -> downgrade -> upgrade
+            self._migrate_up(engine, ver, with_data=True)
-            self._migrate_up(engine, ver_up, with_data=True)
-            if snake_walk:
-                downgraded = self._migrate_down(engine,
-                                                ver_down,
-                                                with_data=True,
-                                                next_version=ver_up)
-                if downgraded:
-                    self._migrate_up(engine, ver_up)
-
-        if downgrade:
-            # Now walk it back down to 0 from the latest, testing
-            # the downgrade paths.
-            up_and_down_versions.reverse()
-            for ver_up, ver_down in up_and_down_versions:
-                # downgrade -> upgrade -> downgrade
-                downgraded = self._migrate_down(engine,
-                                                ver_down, next_version=ver_up)
-
-                if snake_walk and downgraded:
-                    self._migrate_up(engine, ver_up)
-                    self._migrate_down(engine, ver_down, next_version=ver_up)
 
     def _get_version_from_db(self, engine):
         """Returns latest version from db for each type of migrate repo."""
@@ -146,27 +125,6 @@ class BaseWalkMigrationTestCase(object):
 
         self._alembic_command(cmd, engine, self.ALEMBIC_CONFIG, version)
 
-    def _migrate_down(self, engine, version, with_data=False,
-                      next_version=None):
-        try:
-            self._migrate(engine, version, 'downgrade')
-        except NotImplementedError:
-            # NOTE(sirp): some migrations, namely release-level
-            # migrations, don't support a downgrade.
-            return False
-        self.assertEqual(version, self._get_version_from_db(engine))
-
-        # NOTE(sirp): `version` is what we're downgrading to (i.e. the 'target'
-        # version). So if we have any downgrade checks, they need to be run for
-        # the previous (higher numbered) migration.
-        if with_data:
-            post_downgrade = getattr(
-                self, "_post_downgrade_%s" % next_version, None)
-            if post_downgrade:
-                post_downgrade(engine)
-
-        return True
-
     def _migrate_up(self, engine, version, with_data=False):
         """migrate up to a new version of the db.