cannot enable learn plugin

[indirectlylit]

Steps to repo:

• rename your kolibri settings file
  • (e.g. from ~/.kolibri/kolibri_settings.json to ~/.kolibri/kolibri_settings.json.backup)
• run kolibri plugin kolibri.plugins.learn enable

I get

Traceback (most recent call last):
  File "/Users/d/PythonEnvs/kolibri/bin/kolibri", line 9, in <module>
    load_entry_point('kolibri', 'console_scripts', 'kolibri')()
  File "/Users/d/Projects/learning_equality/repos/kolibri/kolibri/utils/cli.py", line 268, in main
    plugin(plugin_name, **arguments)
  File "/Users/d/Projects/learning_equality/repos/kolibri/kolibri/utils/cli.py", line 204, in plugin
    plugin_module = importlib.import_module(plugin_name + ".kolibri_plugin")
  File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/Users/d/Projects/learning_equality/repos/kolibri/kolibri/plugins/learn/kolibri_plugin.py", line 8, in <module>
    from . import hooks, urls
  File "/Users/d/Projects/learning_equality/repos/kolibri/kolibri/plugins/learn/urls.py", line 3, in <module>
    from . import views
  File "/Users/d/Projects/learning_equality/repos/kolibri/kolibri/plugins/learn/views.py", line 4, in <module>
    from kolibri.content.api import get_top_level_topics
  File "/Users/d/Projects/learning_equality/repos/kolibri/kolibri/content/api.py", line 6, in <module>
    from kolibri.content import models as KolibriContent
  File "/Users/d/Projects/learning_equality/repos/kolibri/kolibri/content/models.py", line 13, in <module>
    from mptt.models import MPTTModel, TreeForeignKey
  File "/Users/d/PythonEnvs/kolibri/lib/python2.7/site-packages/mptt/models.py", line 379, in <module>
    class MPTTModel(six.with_metaclass(MPTTModelBase, models.Model)):
  File "/Users/d/PythonEnvs/kolibri/lib/python2.7/site-packages/django/utils/six.py", line 808, in __new__
    return meta(name, bases, d)
  File "/Users/d/PythonEnvs/kolibri/lib/python2.7/site-packages/mptt/models.py", line 262, in __new__
    cls = super_new(meta, class_name, bases, class_dict)
  File "/Users/d/PythonEnvs/kolibri/lib/python2.7/site-packages/django/db/models/base.py", line 94, in __new__
    app_config = apps.get_containing_app_config(module)
  File "/Users/d/PythonEnvs/kolibri/lib/python2.7/site-packages/django/apps/registry.py", line 239, in get_containing_app_config
    self.check_apps_ready()
  File "/Users/d/PythonEnvs/kolibri/lib/python2.7/site-packages/django/apps/registry.py", line 124, in check_apps_ready
    raise AppRegistryNotReady("Apps aren't loaded yet.")
django.core.exceptions.AppRegistryNotReady: Apps aren't loaded yet.

---

Workaround for new Kolibri check-outs:

manually set your settings file to:

{"FIRST_RUN": false, "AUTO_SEARCH_PLUGINS": ["some.plugin.module.path"], "INSTALLED_APPS": ["kolibri.plugins.management", "kolibri.plugins.learn", "kolibri.plugins.document_pdf_render", "kolibri.plugins.video_mp4_render", "kolibri.plugins.audio_mp3_render"]}

[jamalex]

Fixed in 3206d43

[benjaoming]

Two options:

1. Running django.setup() before enabling/disabling a plugin (in kolibri.utils.cli.plugin). That way, we just know that the django stack is ready when loading kolibri_plugin which requires less carefulness when writing plugins.

2. Moving the import of urls modules to MyKolibriPlugin.url_module. This way, we know that loading kolibri_plugin is less error prone because it doesn't depend on a functional django stack. So for instance if a plugin has broken something in the Django stack (for instance its views or models are invalid), we can still enable/disable the plugin.

[benjaoming]

I'm wondering if option 2 is too restrictive. That way, a plugin cannot access its own models when it's being enabled. On the other hand, things like migrations may not have been fired.

Can anybody advice on what plugins currently HAVE to be able to do when enabled? I can't see that any of the core plugins have custom enable() class methods anyways.

[benjaoming]

I'm wondering if option 1 is too restrictive. That way, a plugin cannot access its own models when it's being enabled. On the other hand, things like migrations may not have been fired.

Following up on this: Since one may run enable->disable->enable, with each operation starting and exiting Kolibri, I believe that plugins should not make lots of assumptions about initial states while running enable. This is just a caution.

Anyways, because commands such as collectstatic and migrate have to be run, we also have to run django.setup() anyways.

Here's a rough vision of what enabling a plugin could look like:

$ kolibri plugin enable kolibri.plugins.learn

Enabling plugin: kolibri.plugins.learn

Verifying dependencies... OK!
Collecting static assets (JS/CSS/images)........ OK!
Running database migrations............ OK!

Plugin enabled. Please start/restart Kolibri.

[benjaoming]

Replacing this issue with #2510