Create audit_table trigger in alembic migration

[jacobsvante]

Why isn't the audit_table() trigger added to new tables that are created with alembic revision --autogenerate? Am I correct in suspecting that Alembic doesn't support this?

If so, perhaps we could add a section in the documentation about using alembic's rewriter functionality to achieve this instead. This is how I'm currently solving it in my env.py:

from alembic import context
from alembic.autogenerate import rewriter
from alembic.operations import ops

writer = rewriter.Rewriter()


@writer.rewrites(ops.CreateTableOp)
def create_table(context, revision, op):
    return [
        op,
        ops.ExecuteSQLOp("SELECT audit_table('{}');".format(op.table_name)),
    ]


def run_migrations_online():
    context.configure(
        process_revision_directives=writer,
...

It should be noted that the __versioned__ attribute isn't respected when doing it this way. AFAIK the model isn't available in this context, but perhaps __versioned__ could be passed to the table. Maybe you have some idea on how to achieve this, @kvesteri?

[kvesteri]

This sounds really good! I'm fine with passing __versioned__ to the table or passing it to the info attribute of the Table object. I haven't worked with alembic rewriters so my guess is as good as yours.

[jacobsvante]

Sweet. Let's just wait for zzzeek/alembic#20 to be merged before actually writing the documentation 😉.

[jacobsvante]

Just a heads up that the @zzzeek merged the PR 24 days ago.