Merge "add engine parameter for offline migrations"

etc/neutron.conf

@@ -414,6 +414,10 @@ admin_password = %SERVICE_PASSWORD%
 # main neutron server. (Leave it as is if the database runs on this host.)
 # connection = sqlite://
 
+# Database engine for which script will be generated when using offline
+# migration
+# engine =
+
 # The SQLAlchemy connection string used to connect to the slave database
 # slave_connection =
 

neutron/db/migration/alembic_migrations/env.py

@@ -48,16 +48,19 @@ target_metadata = model_base.BASEV2.metadata
 def run_migrations_offline():
     """Run migrations in 'offline' mode.
 
-    This configures the context with just a URL
-    and not an Engine, though an Engine is acceptable
-    here as well.  By skipping the Engine creation
-    we don't even need a DBAPI to be available.
+    This configures the context with either a URL
+    or an Engine.
 
     Calls to context.execute() here emit the given string to the
     script output.
 
     """
-    context.configure(url=neutron_config.database.connection)
+    kwargs = dict()
+    if neutron_config.database.connection:
+        kwargs['url'] = neutron_config.database.connection
+    else:
+        kwargs['dialect_name'] = neutron_config.database.engine
+    context.configure(**kwargs)
 
     with context.begin_transaction():
         context.run_migrations(active_plugins=active_plugins,

neutron/db/migration/cli.py

@@ -47,11 +47,14 @@ _db_opts = [
                default='',
                secret=True,
                help=_('URL to database')),
+    cfg.StrOpt('engine',
+               default='',
+               help=_('Database engine')),
 ]
 
 CONF = cfg.ConfigOpts()
-CONF.register_opts(_core_opts)
-CONF.register_opts(_db_opts, 'database')
+CONF.register_cli_opts(_core_opts)
+CONF.register_cli_opts(_db_opts, 'database')
 CONF.register_opts(_quota_opts, 'QUOTAS')