[Feature] support creating/dropping extensions about alembic_utils HOT 3 CLOSED

Thought about this some more

Support for CREATE EXTENSION and DROP EXTENSION is probably the 99% use case. Additional support for ALTER statements could be added in the future in a backwards compatible way so there's no need to get hung up on that now

alembic_utils.pg_extension.PGExtension has been added and is available on pypi in alembic_utils>=0.7.0

from alembic_utils.

Its a little trickier than you might think depending on how much functionality that class would have

Support for creating a dropping an extension would be easy

CREATE EXTENSION [ IF NOT EXISTS ] extension_name
    [ WITH ] [ SCHEMA schema_name ]
             [ VERSION version ]
             [ FROM old_version ]

and

DROP EXTENSION [ IF EXISTS ] extension_name [, ...] [ CASCADE | RESTRICT ]

with comparisons made through pg_available_extensions

But there are several alter commands and not all of them are reversible (to produce the down migration).

For example

ALTER EXTENSION name UPDATE [ TO new_version ]

there is no equivalent downgrade statement because postgres extensions aren't expected to implement down migrations for the sql bindings. See the migration upgrade files in the pgsql-http extension in the form http--<old_version>--<new_version>.sql.

Most of those alter statements could likely be ignored/unsupported but ALTER EXTENSION name SET SCHEMA new_schema would need to work vs dropping and recreating the extension if the schema associated with PGExtension changed.

The ReplaceableEntity structure but that class is best suited for entities that implement CREATE OR REPLACE. I have broken that rule before with some success but its never fun.

With that context, if you'd like to open a PR that implements the minimal CREATE/DROP/SET SCHEMA operations with test coverage I'm definitely interested in the feature.

I'll leave this open to track future discussion wrt extensions

from alembic_utils.

That was quick, many thanks!

from alembic_utils.