Fix aggregate_hosts.host migration for sqlite

* Make sure data is not lost during migration
* Changes migration 111_general_aggregates
* Adds test for change

Fix bug 1053131

Change-Id: Idbf0cbd5fdb7758ea1794019807d83d159270cba

2 files changed, 25 insertions, 2 deletions

diff --git a/nova/db/sqlalchemy/migrate_repo/versions/111_general_aggregates.py b/nova/db/sqlalchemy/migrate_repo/versions/111_general_aggregates.py
index 0c97112ce..df4a83843 100644
--- a/nova/db/sqlalchemy/migrate_repo/versions/111_general_aggregates.py
+++ b/nova/db/sqlalchemy/migrate_repo/versions/111_general_aggregates.py
@@ -43,8 +43,7 @@ def upgrade(migrate_engine):
 
     aggregate_hosts = Table('aggregate_hosts', meta, autoload=True)
     if dialect.startswith('sqlite'):
-        aggregate_hosts.drop_column('host')
-        aggregate_hosts.create_column(Column('host', String(255)))
+        aggregate_hosts.c.host.alter(unique=False)
     elif dialect.startswith('postgres'):
         ucon = UniqueConstraint('host',
                                 name='aggregate_hosts_host_key',
diff --git a/nova/tests/test_migrations.py b/nova/tests/test_migrations.py
index 73b50c280..1e8714b94 100644
--- a/nova/tests/test_migrations.py
+++ b/nova/tests/test_migrations.py
@@ -456,3 +456,27 @@ class TestMigrations(test.TestCase):
             sm_vols = sqlalchemy.select([sm_volume.c.id]).execute().fetchall()
             self.assertEqual(set([sm_vol.id for sm_vol in sm_vols]),
                              set([vol1_id]))
+
+    def test_migration_111(self):
+        for key, engine in self.engines.items():
+            migration_api.version_control(engine, TestMigrations.REPOSITORY,
+                                          migration.INIT_VERSION)
+            migration_api.upgrade(engine, TestMigrations.REPOSITORY, 110)
+
+            metadata = sqlalchemy.schema.MetaData()
+            metadata.bind = engine
+            aggregate_hosts = sqlalchemy.Table('aggregate_hosts', metadata,
+                    autoload=True)
+            host = 'host'
+            aggregate_hosts.insert().values(id=1,
+                    aggregate_id=1, host=host).execute()
+
+            migration_api.upgrade(engine, TestMigrations.REPOSITORY, 111)
+            agg = sqlalchemy.select([aggregate_hosts.c.host]).execute().first()
+            self.assertEqual(host, agg.host)
+            aggregate_hosts.insert().values(id=2,
+                    aggregate_id=2, host=host).execute()
+
+            migration_api.downgrade(engine, TestMigrations.REPOSITORY, 111)
+            agg = sqlalchemy.select([aggregate_hosts.c.host]).execute().first()
+            self.assertEqual(host, agg.host)