Even better, what would it take to try using Alembic? (http://alembic.readthedocs.org/en/latest/front.html#project-homepage)
It's a big improvement over sqlalchemy. Amongst other things, migrations are not numbered, they are linked by dependancy, and run in topological-sort order. That there eliminates alot of "my migration number got taken... again..." problems. On Apr 27, 2012, at 10:47 AM, Dan Prince wrote: > > > ----- Original Message ----- >> From: "Sean Dague" <sda...@linux.vnet.ibm.com> >> To: openstack@lists.launchpad.net >> Sent: Friday, April 27, 2012 10:21:17 AM >> Subject: Re: [Openstack] database migration cleanup >> >> On 04/26/2012 03:24 PM, Dan Prince wrote: >> <snip> >>> I think this scheme would support users who follow stable releases >>> as well as users who follow trunk very closely. >>> >>> We talked about this at the conference but I thought this issue >>> might be near and dear to some of our end users so it was worth >>> discussing on the list. >>> >>> What are general thoughts on this approach? >> >> Is there any support in sqlalchemy, or related tools, to handle >> migrations the way rails does, where a schema file is created at the >> end >> of every migration? It would be ideal if we both had a full migration >> history, as well as a short cut at any snap shot to get to the end. > > Ah. Yes, the Rails schema.rb. I looked around for just this sort of thing and > didn't find much. Python-migrate has some "experimental" support for > generating models and I did make use of that initially. See 'create_model' > below: > > > [root@nova1 migrate_repo]# python ./manage.py --repository=./ > --url=mysql://nova:password@localhost/nova > Usage: manage.py COMMAND ... > > Available commands: > compare_model_to_db - compare MetaData against the current > database state > create - create an empty repository at the > specified path > create_model - dump the current database as a Python > model to stdout > db_version - show the current version of the > repository under version control > downgrade - downgrade a database to an earlier > version > drop_version_control - removes version control from a database > help - displays help on a given command > make_update_script_for_model - create a script changing the old > MetaData to the new (current) MetaData > manage - creates a Python script that runs > Migrate with a set of default values > script - create an empty change Python script > script_sql - create empty change SQL scripts for > given database > source - display the Python code for a particular > version in this repository > test - performs the upgrade and downgrade > command on the given database > update_db_from_model - modify the database to match the > structure of the current MetaData > upgrade - upgrade a database to a later version > version - display the latest version available in > a repository > version_control - mark a database as under this > repository's version control > > ---- > > python-migrate's 'create_model' does not however give you something that > exactly matches the schema you'd get by running the all the migrations. So > auto generation doesn't appear to be an option right now. It would be nice to > contribute python-migrate in this regard and get better support for model > generation, etc. Maybe a good long term goal? > > Dan > > >> >> -Sean >> >> -- >> Sean Dague >> IBM Linux Technology Center >> email: slda...@us.ibm.com >> alt-email: sda...@linux.vnet.ibm.com >> >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~openstack >> Post to : openstack@lists.launchpad.net >> Unsubscribe : https://launchpad.net/~openstack >> More help : https://help.launchpad.net/ListHelp >> > > _______________________________________________ > Mailing list: https://launchpad.net/~openstack > Post to : openstack@lists.launchpad.net > Unsubscribe : https://launchpad.net/~openstack > More help : https://help.launchpad.net/ListHelp -- Monsyne M. Dragon OpenStack/Nova cell 210-441-0965 work x 5014190 _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : openstack@lists.launchpad.net Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
