Hello Craig, There's unfortunately no way to hook into the migration auto-detector to specify additional operations to be added.
What I suggest you do instead is dynamically inject operations in the plan that is about to be run by connecting a pre_migrate signal. When you detect CreateModel operations for subclasses of your AbtractModel you could insert operations to be performed before and after them. This is pattern we use internally to perform ContentType rename on RenameModel operations[0]. As for the makemigrations hooks I think it would require a lot of thought and efforts to get right. Right now the auto-detector is a black box that deals with dependencies and model state deltas resolution. In an ideal world model/fields objects would be able to generate the list of operations they require to move from state A to B as a public API and the auto-detector would simply iterate over the existing migrations state models and compare them against the current state of the project. Best, Simon [0] https://github.com/django/django/blob/525dc283a68c0d47f5eb2192cc4a20111d561ae0/django/contrib/contenttypes/management/__init__.py#L45-L84 Le mardi 6 juin 2017 16:45:05 UTC-4, Craig de Stigter a écrit : > > Hi there > > I'm in the early stages of developing a third party app which makes heavy > use of postgres extensions. The app provides an abstract model, so I won't > have direct control of user's models or migrations. I'm having trouble > getting it to generate sensible migrations for users. > > At present the migration process for users is going to be "copy and paste > my migration file template into your project, and change the model names to > match your app". As far as I can tell there is no way to generate > migrations with anything custom. > > The operations I need to generate are: > > - CreateExtension() > - RunSQL() - (to create slightly non-standard constraints) > > e.g. perhaps my model could supply a couple of methods: > > - Model.Meta.pre_creation_operations() - returns a list of operations > to apply before the auto-detected model operations, e.g. creating > extensions etc > - Model.Meta.post_creation_operations() - the same but applied after > the auto-detected operations, e.g. adding constraints/indexes. > > I'm envisaging that the operations returned from both methods would be > deconstructed and copied into migration files when makemigrations is run. > > Has there been any discussion about this previously? I haven't found any. > > Thanks > Craig de Stigter > -- You received this message because you are subscribed to the Google Groups "Django developers (Contributions to Django itself)" group. To unsubscribe from this group and stop receiving emails from it, send an email to django-developers+unsubscr...@googlegroups.com. To post to this group, send email to django-developers@googlegroups.com. Visit this group at https://groups.google.com/group/django-developers. To view this discussion on the web visit https://groups.google.com/d/msgid/django-developers/a152a3df-5bac-4aaa-8103-fb85194e78c0%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
