File Support

If you do a lazy sync and then hit up the http GET :8000/pulp/api/v3/content/file/files/ endpoint, you're greeted with a 500 error and the following traceback:

Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]: pulp: django.request:ERROR: Internal Server Error: /pulp/api/v3/content/file/files/
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]: Traceback (most recent call last):
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/django/db/models/options.py", line 564, in get_field
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     return self.fields_map[field_name]
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]: KeyError: 'artifact'
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]: During handling of the above exception, another exception occurred:
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]: Traceback (most recent call last):
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/django/db/models/base.py", line 635, in serializable_value
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     field = self._meta.get_field(field_name)
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/django/db/models/options.py", line 566, in get_field
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     raise FieldDoesNotExist("%s has no field named '%s'" % (self.object_name, field_name))
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]: django.core.exceptions.FieldDoesNotExist: FileContent has no field named 'artifact'
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]: During handling of the above exception, another exception occurred:
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]: Traceback (most recent call last):
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/django/core/handlers/exception.py", line 34, in inner
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     response = get_response(request)
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/django/core/handlers/base.py", line 126, in _get_response
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     response = self.process_exception_by_middleware(e, request)
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/django/core/handlers/base.py", line 124, in _get_response
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     response = wrapped_callback(request, *callback_args, **callback_kwargs)
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     return view_func(*args, **kwargs)
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/rest_framework/viewsets.py", line 116, in view
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     return self.dispatch(request, *args, **kwargs)
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/rest_framework/views.py", line 495, in dispatch
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     response = self.handle_exception(exc)
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/rest_framework/views.py", line 455, in handle_exception
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     self.raise_uncaught_exception(exc)
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/rest_framework/views.py", line 492, in dispatch
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     response = handler(request, *args, **kwargs)
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/rest_framework/mixins.py", line 45, in list
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     return self.get_paginated_response(serializer.data)
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/rest_framework/serializers.py", line 765, in data
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     ret = super(ListSerializer, self).data
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/rest_framework/serializers.py", line 262, in data
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     self._data = self.to_representation(self.instance)
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/rest_framework/serializers.py", line 683, in to_representation
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     self.child.to_representation(item) for item in iterable
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/rest_framework/serializers.py", line 683, in <listcomp>
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     self.child.to_representation(item) for item in iterable
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/rest_framework/serializers.py", line 514, in to_representation
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     attribute = field.get_attribute(instance)
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/rest_framework/relations.py", line 182, in get_attribute
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     value = attribute_instance.serializable_value(self.source_attrs[-1])
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/django/db/models/base.py", line 637, in serializable_value
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     return getattr(self, field_name)
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/pulp_file/app/models.py", line 33, in artifact
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     return self._artifacts.get().pk
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/django/db/models/manager.py", line 82, in manager_method
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     return getattr(self.get_queryset(), name)(*args, **kwargs)
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:   File "/usr/local/lib/pulp/lib64/python3.7/site-packages/django/db/models/query.py", line 399, in get
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]:     self.model._meta.object_name
Dec 20 18:18:08 p3.pulp.vm gunicorn[10767]: pulpcore.app.models.content.Artifact.DoesNotExist: Artifact matching query does not exist

The problem is that if you use lazy sync, there's no artifact, so this code will fail.

    @property
    def artifact(self):
        """
        Return the artifact id (there is only one for this content type).
        """
        return self._artifacts.get().pk

This problem is not specific to the file plugin, it's one which probably affects every plugin that copied this setter... which is all of them?

A simple fix to this would be to do something like this:

        x = self._artifacts.first()
        if x is None:
            return None
        return x.pk

Then, when the "artifact" has not yet been created, it would be listed as "null".