How to change the name of a Django app?

How to change the name of a Django app?

I have changed the name of an app in Django by renaming its folder, imports and all its references (templates/indexes). But now I get this error when I try to run python manage.py runserver
Error: Could not import settings 'nameofmynewapp.settings' (Is it on sys.path?): No module named settings

How can I debug and solve this error? Any clues?

Solutions/Answers:

Answer 1:

Follow these steps to change an app’s name in Django:

  1. Rename the folder which is in your project root
  2. Change any references to your app in their dependencies, i.e. the app’s views.py, urls.py , ‘manage.py’ , and settings.py files.
  3. Edit the database table django_content_type with the following command: UPDATE django_content_type SET app_label='<NewAppName>' WHERE app_label='<OldAppName>'
  4. Also if you have models, you will have to rename the model tables. For postgres use ALTER TABLE <oldAppName>_modelName RENAME TO <newAppName>_modelName. For mysql too I think it is the same (as mentioned by @null_radix)
  5. (For Django >= 1.7) Update the django_migrations table to avoid having your previous migrations re-run: UPDATE django_migrations SET app='<NewAppName>' WHERE app='<OldAppName>'. Note: there is some debate (in comments) if this step is required for Django 1.8+; If someone knows for sure please update here.
  6. If your models.py ‘s Meta Class has app_name listed, make sure to rename that too (mentioned by @will).
  7. If you’ve namespaced your static or templates folders inside your app, you’ll also need to rename those. For example, rename old_app/static/old_app to new_app/static/new_app.
  8. For renaming django models, you’ll need to change django_content_type.name entry in DB. For postgreSQL use UPDATE django_content_type SET name='<newModelName>' where name='<oldModelName>' AND app_label='<OldAppName>'

Meta point (If using virtualenv): Worth noting, if you are renaming the directory that contains your virtualenv, there will likely be several files in your env that contain an absolute path and will also need to be updated. If you are getting errors such as ImportError: No module named ... this might be the culprit. (thanks to @danyamachine for providing this).

Other references: you might also want to refer the below links for a more complete picture

  1. Renaming an app with Django and South
  2. How do I migrate a model out of one django app and into a new one?
  3. How to change the name of a Django app?
  4. Backwards migration with Django South
  5. Easiest way to rename a model using Django/South?
  6. Python code (thanks to A.Raouf) to automate the above steps (Untested code. You have been warned!)
  7. Python code (thanks to rafaponieman) to automate the above steps (Untested code. You have been warned!)

Answer 2:

New in Django 1.7 is a app registry that stores configuration and provides introspection. This machinery let’s you change several app attributes.

The main point I want to make is that renaming an app isn’t always necessary: With app configuration it is possible to resolve conflicting apps. But also the way to go if your app needs friendly naming.

As an example I want to name my polls app ‘Feedback from users’. It goes like this:

Create a apps.py file in the polls directory:

from django.apps import AppConfig

class PollsConfig(AppConfig):
    name = 'polls'
    verbose_name = "Feedback from users"

Add the default app config to your polls/__init__.py:

default_app_config = 'polls.apps.PollsConfig'

For more app configuration: https://docs.djangoproject.com/en/1.7/ref/applications/

Answer 3:

In case you are using PyCharm and project stops working after rename:

  1. Edit Run/Debug configuration and change environment variable DJANGO_SETTINGS_MODULE, since it includes your project name.
  2. Go to Settings / Languages & Frameworks / Django and update the settings file location.

Answer 4:

Fun problem! I’m going to have to rename a lot of apps soon, so I did a dry run.

This method allows progress to be made in atomic steps, to minimise disruption for other developers working on the app you’re renaming.

See the link at the bottom of this answer for working example code.

  1. Prepare existing code for the move:
    • Create an app config (set name and label to defaults).
    • Add the app config to INSTALLED_APPS.
    • On all models, explicitly set db_table to the current value.
    • Doctor migrations so that db_table was “always” explicitly defined.
    • Ensure no migrations are required (checks previous step).
  2. Change the app label:

    • Set label in app config to new app name.
    • Update migrations and foreign keys to reference new app label.
    • Update templates for generic class-based views (the default path is <app_label>/<model_name>_<suffix>.html)
    • Run raw SQL to fix migrations and content_types app (unfortunately, some raw SQL is unavoidable). You can not run this in a migration.

      UPDATE django_migrations
         SET app = 'catalogue'
       WHERE app = 'shop';
      
      UPDATE django_content_type
         SET app_label = 'catalogue'
       WHERE app_label = 'shop';
      
    • Ensure no migrations are required (checks previous step).

  3. Rename the tables:
    • Remove “custom” db_table.
    • Run makemigrations so django can rename the table “to the default”.
  4. Move the files:
    • Rename module directory.
    • Fix imports.
    • Update app config’s name.
    • Update where INSTALLED_APPS references the app config.
  5. Tidy up:
    • Remove custom app config if it’s no longer required.
    • If app config gone, don’t forget to also remove it from INSTALLED_APPS.

Example solution: I’ve created app-rename-example, an example project where you can see how I renamed an app, one commit at a time.

The example uses Python 2.7 and Django 1.8, but I’m confident the same process will work on at least Python 3.6 and Django 2.1.

Answer 5:

Re-migrate approach for a cleaner plate.

This can painlessly be done IF other apps do not foreign key models from the app to be renamed. Check and make sure their migration files don’t list any migrations from this one.

  1. Backup your database. Dump all tables with a) data + schema for possible circular dependencies, and b) just data for reloading.
  2. Run your tests.
  3. Check all code into VCS.
  4. Delete the database tables of the app to be renamed.
  5. Delete the permissions: delete from auth_permission where content_type_id in (select id from django_content_type where app_label = '<OldAppName>')
  6. Delete content types: delete from django_content_type where app_label = '<OldAppName>'
  7. Rename the folder of the app.
  8. Change any references to your app in their dependencies, i.e. the app’s views.py, urls.py , ‘manage.py’ , and settings.py files.
  9. Delete migrations: delete from django_migrations where app = '<OldAppName>'
  10. If your models.py ‘s Meta Class has app_name listed, make sure to rename that too (mentioned by @will).
  11. If you’ve namespaced your static or templates folders inside your app, you’ll also need to rename those. For example, rename old_app/static/old_app to new_app/static/new_app.
  12. If you defined app config in apps.py; rename those, and rename their references in settings.INSTALLED_APPS
  13. Delete migration files.
  14. Re-make migrations, and migrate.
  15. Load your table data from backups.

References