Make use of 'current' apps so RBAC ImplicitRoleField can work during migrations

While a migration is taking place, we can't juse use normal model
references like Role and RolePermission, nor can we use generic foreign
keys without manually referring to the content type and object id
fields.

awx/main/fields.py

@@ -17,10 +17,11 @@ from django.db.models.fields.related import (
     ReverseManyRelatedObjectsDescriptor,
 )
 from django.utils.encoding import smart_text
+from django.utils.timezone import now
 
 # AWX
-from awx.main.models.rbac import RolePermission, Role, batch_role_ancestor_rebuilding
-
+from awx.main.models.rbac import Role, batch_role_ancestor_rebuilding
+from awx.main.utils import get_current_apps
 
 __all__ = ['AutoOneToOneField', 'ImplicitRoleField']
 
@@ -65,8 +66,12 @@ def resolve_role_field(obj, field):
     else:
         return []
 
+    if obj is None:
+        return []
+
     if len(field_components) == 1:
-        if type(obj) is not ImplicitRoleDescriptor and type(obj) is not Role:
+        Role_ = get_current_apps().get_model('main', 'Role')
+        if type(obj) is not ImplicitRoleDescriptor and type(obj) is not Role_:
             raise Exception(smart_text('{} refers to a {}, not an ImplicitRoleField or Role'.format(field, type(obj))))
         ret.append(obj)
     else:
@@ -174,7 +179,10 @@ class ImplicitRoleField(models.ForeignKey):
         role = getattr(instance, self.name, None)
         if role:
             return role
-        role = Role.objects.create(
+        Role_ = get_current_apps().get_model('main', 'Role')
+        role = Role_.objects.create(
+            created=now(),
+            modified=now(),
             name=self.role_name,
             description=self.role_description
         )
@@ -186,9 +194,16 @@ class ImplicitRoleField(models.ForeignKey):
         role.save()
 
         if self.permissions is not None:
-            permissions = RolePermission(
+            RolePermission_ = get_current_apps().get_model('main', 'RolePermission')
+            ContentType = get_current_apps().get_model('contenttypes', "ContentType")
+            instance_content_type = ContentType.objects.get_for_model(instance)
+
+            permissions = RolePermission_(
+                created=now(),
+                modified=now(),
                 role=role,
-                resource=instance,
+                content_type=instance_content_type,
+                object_id=instance.id,
                 auto_generated=True
             )
 
@@ -253,7 +268,20 @@ class ImplicitRoleField(models.ForeignKey):
         parent_roles = set()
         for path in paths:
             if path.startswith("singleton:"):
-                parents = [Role.singleton(path[10:])]
+                singleton_name = path[10:]
+                Role_ = get_current_apps().get_model('main', 'Role')
+                qs = Role_.objects.filter(singleton_name=singleton_name)
+                if qs.count() >= 1:
+                    role = qs[0]
+                else:
+                    role = Role_.objects.create(
+                               created=now(),
+                               modified=now(),
+                               singleton_name=singleton_name,
+                               name=singleton_name,
+                               description=singleton_name
+                           )
+                parents = [role]
             else:
                 parents = resolve_role_field(instance, path)
             for parent in parents:

awx/main/migrations/0009_v300_rbac_migrations.py

@@ -12,6 +12,7 @@ class Migration(migrations.Migration):
     ]
 
     operations = [
+        migrations.RunPython(rbac.init_rbac_migration),
         migrations.RunPython(rbac.migrate_users),
         migrations.RunPython(rbac.migrate_organization),
         migrations.RunPython(rbac.migrate_team),

awx/main/migrations/_rbac.py

@@ -5,7 +5,7 @@ from django.db.models import Q
 from django.utils.timezone import now
 
 from collections import defaultdict
-from awx.main.utils import getattrd
+from awx.main.utils import getattrd, set_current_apps
 
 import _old_access as old_access
 logger = logging.getLogger(__name__)
@@ -26,6 +26,10 @@ def log_migration(wrapped):
         return wrapped(*args, **kwargs)
     return wrapper
 
+@log_migration
+def init_rbac_migration(apps, schema_editor):
+    set_current_apps(apps)
+
 @log_migration
 def migrate_users(apps, schema_editor):
     User = apps.get_model('auth', "User")

awx/main/utils.py

@@ -20,6 +20,7 @@ import tempfile
 from rest_framework.exceptions import ParseError, PermissionDenied
 from django.utils.encoding import smart_str
 from django.core.urlresolvers import reverse
+from django.apps import apps
 
 # PyCrypto
 from Crypto.Cipher import AES
@@ -30,7 +31,8 @@ __all__ = ['get_object_or_400', 'get_object_or_403', 'camelcase_to_underscore',
            'get_ansible_version', 'get_ssh_version', 'get_awx_version', 'update_scm_url',
            'get_type_for_model', 'get_model_for_type', 'to_python_boolean',
            'ignore_inventory_computed_fields', 'ignore_inventory_group_removal',
-           '_inventory_updates', 'get_pk_from_dict', 'getattrd', 'NoDefaultProvided']
+           '_inventory_updates', 'get_pk_from_dict', 'getattrd', 'NoDefaultProvided',
+           'get_current_apps', 'set_current_apps']
 
 
 def get_object_or_400(klass, *args, **kwargs):
@@ -556,3 +558,11 @@ def getattrd(obj, name, default=NoDefaultProvided):
             return default
         raise
 
+current_apps = apps
+def set_current_apps(apps):
+    global current_apps
+    current_apps = apps
+
+def get_current_apps():
+    global current_apps
+    return current_apps