[Openstack] GLANCE: How to deal with SQLAlchemy-migrate problems

Jay Pipes jaypipes at gmail.com
Mon Mar 21 19:35:43 UTC 2011

On Mon, Mar 21, 2011 at 3:27 PM, Brian Schott <bfschott at gmail.com> wrote:
> I've done a few migration scripts in recent weeks for our nova/hpc-trunk.  It was a painful learning curve mostly because I come from the Perl generation, but I got through it.
> Is the design pattern for migrations written down somewhere?  If not, we should add some instructions to the migrate_repo/README file.
> The transition from austin/bexar.py files where all transforms are in a lump to individual files.  This does have grief This is a good change, but the template example I used didn't have a downgrade function.
> bschott at island100:~/source/nova/nova-trunk/nova/db/sqlalchemy/migrate_repo/versions$ grep downgrade *.py
> 001_austin.py:def downgrade(migrate_engine):
> 008_add_instance_types.py:def downgrade(migrate_engine):
> 010_add_os_type_to_instances.py:def downgrade(migrate_engine):
> My only suggestion to Jay is that it is perfectly acceptable to do a migration in multiple stages.  Less efficient, but it might traverse less untested code in SA-migrate.

Hi Brian,

1) Did you do unit tests on your migration scripts? Did you use
SQLite, MySQL and PostgreSQL?
2) Did you use SQL scripts, not Python change scripts?


More information about the Openstack mailing list