Django Migrations: A Retrospective

Transcript

1. Andrew Godwin @andrewgodwin migrations: a retrospective

2. Andrew Godwin Author of South migrations library Hi, I'm Author

   of 1.7 Django migrations I like my tea iced, and my schemas explicit

3. Django/Python backend I work for Discovery? Mobile? Storage? UI? On-site?

   ...auditing? We have it all. We're hiring!

4. Migrations They're pretty good.

5. South ...it was good for its time

6. The Initial Plan Django Schema backend ORM Hooks South 2

   Migration handling User interface

7. The Revised Plan Django Schema backend ORM Hooks South 2

   Migration handling User interface Backport for 1.4 - 1.6

8. The Revised Revised Plan Django Schema backend ORM Hooks Migration

   handling User interface

9. Logically Separate SchemaEditor Schema Migrations field.deconstruct() ModelOptions.apps Operations Loader /

   Graph Executor Autodetector Optimiser State

10. makemigrations field.deconstruct() Loader / Graph Autodetector Optimiser State Writer 1

    2 State 3 5 4

11. migrate SchemaEditor ModelOptions.apps Operations Loader / Graph Executor State 1

    2 Recorder 3

12. Moving South into Django instead, "Adding migrations to Django"

13. A New Format More concise Declarative Introspectable

14. Migration actions Frozen ORM

15. None

16. In-memory running Creates models from migration sets Autodetector diffs created

    from on-disk Used to feed SchemaEditor / ORM

17. But what went wrong?

18. Swappable Models

19. Your migration dependencies myapp/0001 myapp/0002 otherapp/0001 auth/0001 contenttypes/0001

20. myapp/0001 myapp/0002 otherapp/0001 auth/0001 contenttypes/0001 thirdapp/0001 Your migration dependencies on

    swappable models

21. what? Your migration dependencies on swappable models myapp/0001 myapp/0002 otherapp/0001

    auth/0001 contenttypes/0001 thirdapp/0001 ???

22. what? Your migration dependencies on swappable models myapp/0001 myapp/0002 otherapp/0001

    auth/0001 contenttypes/0001 thirdapp/0001 ???

23. Unmigrated Apps

24. Test persistence

25. Test persistence on MySQL

26. Random Meta options order_with_respect_to? Really?

27. Proxy Models

28. But we're close! Django 1.7, coming to a server near

    you soon.

29. Thanks! Andrew Godwin andrewgodwin@eventbrite.com