Make sure tenant models are cached when required.

tenancy/auth/backends.py

@@ -29,7 +29,7 @@ def __init__(self):
                 "`tenancy.middleware.GlobalTenantMiddleware` does "
                 "just that." % attr_name
             )
-        self.tenant_user_model = user_model.for_tenant(tenant)
+        self.tenant_user_model = tenant.models[user_model]
 
     def authenticate(self, username=None, password=None, **kwargs):
         if username is None:

tenancy/forms.py

@@ -10,7 +10,7 @@ def _get_tenant_model(tenant, model):
         raise ImproperlyConfigured(
             "%s must be an instance of TenantModelBase" % model.__name__
         )
-    return model.for_tenant(tenant)
+    return tenant.models[model]
 
 
 def tenant_modelform_factory(tenant, form):

tenancy/management/commands/createsuperuser.py

@@ -31,7 +31,7 @@ def __init__(self):
     def handle(self, *args, **kwargs):
         tenant = kwargs.get('tenant')
         if tenant:
-            self.UserModel = self.UserModel.for_tenant(tenant)
+            self.UserModel = tenant.models[self.UserModel]
         elif self.tenant_auth_user_model:
             raise CommandError(
                 "Since your swapped `AUTH_USER_MODEL` is tenant specific "

tenancy/models.py

@@ -18,7 +18,7 @@
 from django.db.models.fields.related import add_lazy_relation
 from django.db.models.loading import get_model
 from django.dispatch.dispatcher import receiver
-from django.utils.six import with_metaclass, string_types
+from django.utils.six import itervalues, string_types, with_metaclass
 from django.utils.six.moves import copyreg
 
 from . import get_tenant_model
@@ -29,7 +29,23 @@
     receivers_for_model, remove_from_app_cache)
 
 
-class TenantModelsCache(object):
+class TenantModels(object):
+    __slots__ = ['references']
+
+    def __init__(self, tenant):
+        self.references = OrderedDict((
+            (reference, reference.for_tenant(tenant))
+            for reference in TenantModelBase.references
+        ))
+
+    def __getitem__(self, key):
+        return self.references[key]
+
+    def __iter__(self, **kwargs):
+        return itervalues(self.references, **kwargs)
+
+
+class TenantModelsDescriptor(object):
     def contribute_to_class(self, cls, name):
         self.name = name
         setattr(cls, name, self)
@@ -43,10 +59,7 @@ def __get__(self, instance, owner):
         try:
             models = instance.__dict__[self.name]
         except KeyError:
-            models = tuple(
-                reference.for_tenant(instance)
-                for reference in TenantModelBase.references
-            )
+            models = TenantModels(instance)
             self.__set__(instance, models)
         return models
 
@@ -86,7 +99,7 @@ def delete(self, *args, **kwargs):
     def natural_key(self):
         raise NotImplementedError
 
-    models = TenantModelsCache()
+    models = TenantModelsDescriptor()
 
     @contextmanager
     def as_global(self):
@@ -142,7 +155,7 @@ def db_schema_table(tenant, db_table):
 
 
 class Reference(object):
-    __slots__ = ('model', 'bases', 'Meta', 'related_names')
+    __slots__ = ['model', 'bases', 'Meta', 'related_names']
 
     def __init__(self, model, Meta, related_names=None):
         self.model = model
@@ -551,15 +564,15 @@ def __pickle_tenant_model_base(model):
 
 
 class TenantModelDescriptor(object):
-    __slots__ = ('model',)
+    __slots__ = ['model']
 
     def __init__(self, model):
         self.model = model
 
     def __get__(self, tenant, owner):
         if not tenant:
             return self
-        return self.model.for_tenant(tenant)._default_manager
+        return tenant.models[self.model]._default_manager
 
 
 class TenantModel(with_metaclass(TenantModelBase, models.Model)):

tenancy/tests/test_commands.py

@@ -55,13 +55,15 @@ def test_verbosity(self):
         tenant = Tenant.objects.get(name='tenant')
         stdout.seek(0)
         connection = connections[tenant._state.db]
-        if connection.vendor == 'postgresql':
-            self.assertIn(tenant.db_schema, stdout.readline())
-        for model in TenantModelBase.references:
-            self.assertIn(model._meta.object_name, stdout.readline())
-            self.assertIn(model._meta.db_table, stdout.readline())
-        self.assertIn('Installing indexes ...', stdout.readline())
-        tenant.delete()
+        try:
+            if connection.vendor == 'postgresql':
+                self.assertIn(tenant.db_schema, stdout.readline())
+            for model in TenantModelBase.references:
+                self.assertIn(model._meta.object_name, stdout.readline())
+                self.assertIn(model._meta.db_table, stdout.readline())
+            self.assertIn('Installing indexes ...', stdout.readline())
+        finally:
+            tenant.delete()
 
     @setup_custom_tenant_user
     @mock_inputs((

tenancy/tests/test_models.py

@@ -108,12 +108,21 @@ def test_model_garbage_collection(self):
             self.assertIsNone(model_wref())
 
 
-class TenantModelsCacheTest(TenancyTestCase):
-    def test_initialized_models(self):
-        """
-        Make sure models are loaded upon model initialization.
-        """
-        self.assertIn('models', self.tenant.__dict__)
+class TenantModelsDescriptorTest(TenancyTestCase):
+    def setUp(self):
+        super(TenantModelsDescriptorTest, self).setUp()
+        Tenant.objects.clear_cache()
+
+    def test_uncached_upon_tenant_initialization(self):
+        """Make sure models are not created upon model initialization."""
+        tenant = Tenant.objects.get(pk=self.tenant.pk)
+        self.assertNotIn('models', tenant.__dict__)
+
+    def test_created_models_upon_cache_access(self):
+        """Make sure all tenant models are created upon cache access."""
+        tenant = Tenant.objects.get(pk=self.tenant.pk)
+        for reference in TenantModelBase.references:
+            tenant.models[reference]
 
 
 class TenantModelBaseTest(TenancyTestCase):

tenancy/views.py

@@ -52,7 +52,8 @@ def get_model(self):
         )
 
     def get_tenant_model(self):
-        return self.get_model().for_tenant(self.get_tenant())
+        tenant = self.get_tenant()
+        return tenant.models[self.get_model()]
 
     def get_queryset(self):
         return self.get_tenant_model()._default_manager.all()