On Tue, Feb 18, 2020, at 1:17 PM, Brian Hill wrote:
> Is there a way to move the alembic_version table in the Public schema
> (postgres) to a specific schema (mult-tenant) as part of a migration?
I highly doubt this is possible in the general case without the raw SQL in your
env.py, because as the migration runs, the environment needs to update the
table. if it moves schemas, then it won't be updating the correct table
anymore. You would have to manipulate the internal state of the
MigrationContext within the migration script so that this doesnt happen,
however, the migration is also occurring inside of a transaction so it's very
likely that you wouldn't actually be able to fully drop the old table in every
case and there could be other side effects of this as well, and I cant
guarantee this internal manipulation will always work for new Alembic releases.
>
> I want alembic to read the inital version from Public.alembic_version and
> then write the new upgraded version to the specific schema.alembic_version.
>
> The only way I can get it to work is executing raw sql after the migration,
> and this won't work for future migrations.
>
> with context.begin_transaction():
> context.run_migrations()
> context.execute(f'alter table Public.alembic_version set schema {DB_SCHEMA}')
I think what you can do here is check for alembic_version in the old schema and
in the new one and then move the table after the migrations but only if it
needs to be moved. Basically have the migrations always run with the schema
whereever it is to start with, then move it after the fact.
you'd have to detect which schema to use before you configure the context,
however, since you need to pass it the schema for the alembic_version table.
>
> Do I have to flatten/rebase my versions after this?
>
> Thanks,
>
> Brian
>
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