Migrations management can be improved

[ccrisan]

Currently Colibris migrations management is based on peewee-migrate. Problems include:

• no abstract models support
• buggy column defaults

Alternatives:

• peewee-moves

[AMecea]

Hi @ccrisan, A possible implementations can be to use the peewee-moves CLI structure, as they did for Flask. This will drop the migrate and makemigrations commands for a new group command called db. In this case, would be something like:

$ ./manage.py db --help
Usage: ./manage.py db [OPTIONS] COMMAND [ARGS]...

    Run database migration commands.

Commands:
    create     Create a migration based on an existing model.
    delete     Delete the target migration from the filesystem and database.
    downgrade  Run database downgrades.
    info       Show information about the current database.
    revision   Create a blank migration file.
    status     Show information about the database.
    upgrade    Run database upgrades.

What do you think about this?
Thanks!

[ccrisan]

@AMecea I honestly have no problem adding a db group of commands. @lucifurtun what do you think about this approach?

[lucifurtun]

@AMecea , @ccrisan , I don't see any problem in getting rid of migrate and makemigrations commands and switching to db <command>. I'm more concerned if peewee-moves is a good option.

[ccrisan]

@lucifurtun peewee-moves is definitely better than peewee-migrate and currently one of the only 3 options we have (the 3rd one being peewee-migrate2).

@zalmanu and the team have been playing with it for some time now and they even submitted PRs upstream; they seem pretty confident about it being the correct solution, for now.

[AMecea]

The inconveniences that I found so far with peewee-moves are:

• The model package has to be specified when creating a migration. The "makemigrations" command will be something like: ./manage.py db create .models

• it doesn't create update migrations it only creates simple "create table" migrations. More complex migration has to be written manually. This is specified in their documentation too:

This currently only supports creating models. If your model changes, it’s up to you to write the migration to support that.

[ccrisan]

@AMecea then it might be worth looking into https://github.com/spumer/peewee_migrate2. One big advantage would be that it's practically compatible with existing colibris management commands and code.

[AMecea]

@ccrisan I'm not sure that peewee_migrate2 will solve the above issues (abstract models and buggy columns defaults). But the implementation is straight forward. Also, I would like to use the same approach, to have a group command, similar to peewee-moves. This will give more control to the user (e.g. rollback, list, merge)

I've opened a PR with the peewee-migrate2 implementation: #49, the peewee-moves implementation is similar.