Extended the setup methods in pre and post phase. Fixes #27.

configurations/base.py

@@ -59,5 +59,9 @@ class Settings(six.with_metaclass(SettingsBase)):
 
     """
     @classmethod
-    def setup(cls):
+    def pre_setup(cls):
+        pass
+
+    @classmethod
+    def post_setup(cls):
         pass

configurations/importer.py

@@ -160,6 +160,7 @@ class SettingsLoader(object):
         else:
             mod = imp.load_module(fullname, *self.location)
         cls_path = '%s.%s' % (mod.__name__, self.name)
+
         try:
             cls = getattr(mod, self.name)
         except AttributeError as err:  # pragma: no cover
@@ -167,9 +168,10 @@ class SettingsLoader(object):
                     "While trying to find the '%s' settings in module '%s'" %
                     (self.name, mod.__package__))
         try:
-            cls.setup()
+            cls.pre_setup()
         except Exception as err:
-            reraise(err, "While calling '%s.setup()'" % cls_path)
+            reraise(err, "While calling '%s.pre_setup()'" % cls_path)
+
         try:
             obj = cls()
         except Exception as err:
@@ -193,4 +195,10 @@ class SettingsLoader(object):
             setattr(mod, name, value)
 
         setattr(mod, 'CONFIGURATION', '%s.%s' % (fullname, self.name))
+
+        try:
+            cls.post_setup()
+        except Exception as err:
+            reraise(err, "While calling '%s.post_setup()'" % cls_path)
+
         return mod

configurations/tests/settings/main.py

@@ -54,5 +54,11 @@ class Test(Settings):
         return 5
 
     @classmethod
-    def setup(cls):
-        cls.SETUP_TEST_SETTING = 6
+    def pre_setup(cls):
+        cls.PRE_SETUP_TEST_SETTING = 6
+
+    @classmethod
+    def post_setup(cls):
+        cls.POST_SETUP_TEST_SETTING = 7
+        from django.conf import settings
+        settings.POST_SETUP_TEST_SETTING = 8

configurations/tests/test_main.py

@@ -25,7 +25,8 @@ class MainTests(TestCase):
                          global_settings.TEMPLATE_CONTEXT_PROCESSORS + (
                              'configurations.tests.settings.base.test_callback',
                          ))
-        self.assertEqual(main.SETUP_TEST_SETTING, 6)
+        self.assertEqual(main.PRE_SETUP_TEST_SETTING, 6)
+        self.assertRaises(AttributeError, lambda: main.POST_SETUP_TEST_SETTING)
 
     def test_global_arrival(self):
         from django.conf import settings
@@ -35,7 +36,8 @@ class MainTests(TestCase):
         self.assertTrue(lambda: callable(settings.PRISTINE_LAMBDA_SETTING))
         self.assertNotEqual(settings.PRISTINE_FUNCTION_SETTING, 5)
         self.assertTrue(lambda: callable(settings.PRISTINE_FUNCTION_SETTING))
-        self.assertEqual(settings.SETUP_TEST_SETTING, 6)
+        self.assertEqual(settings.PRE_SETUP_TEST_SETTING, 6)
+        self.assertEqual(settings.POST_SETUP_TEST_SETTING, 8)
 
     @patch.dict(os.environ, clear=True, DJANGO_CONFIGURATION='Test')
     def test_empty_module_var(self):

docs/index.rst

@@ -160,9 +160,10 @@ Setup methods
 
 .. versionadded:: 0.3
 
-If there is something required to be set up after all the settings have been
-loaded please override the ``setup`` class method like so (don't forget
-to apply the Python ``@classmethod`` decorator::
+If there is something required to be set up before or after the settings
+loading happens, please override the ``pre_setup`` or ``post_setup``
+class methods like so (don't forget to apply the Python ``@classmethod``
+decorator::
 
     from configurations import Settings
 
@@ -170,11 +171,22 @@ to apply the Python ``@classmethod`` decorator::
         # ...
 
         @classmethod
-        def setup(cls):
+        def pre_setup(cls):
             if something.completely.different():
                 cls.DEBUG = True
 
-Or do something unrelated to your settings, like connecting to a database::
+        @classmethod
+        def post_setup(cls):
+            print("done setting up! \o/")
+
+As you can see above the ``pre_setup`` method can also be used to
+programmatically change a class attribute of the settings class and it
+will be taken into account when doing the rest of the settings setup.
+Of course that won't work for ``post_setup`` since that's when the
+settings setup is already done.
+
+In fact you can easily do something unrelated to settings, like
+connecting to a database::
 
     from configurations import Settings
 
@@ -182,10 +194,22 @@ Or do something unrelated to your settings, like connecting to a database::
         # ...
 
         @classmethod
-        def setup(cls):
+        def post_setup(cls):
             import mango
             mango.connect('enterprise')
 
+
+.. warning::
+
+    You could do the same by overriding the ``__init__`` method of your
+    settings class but this may cause hard to debug errors because
+    at the time the ``__init__`` method is called (during Django startup)
+    the Django setting system isn't fully loaded yet.
+
+    So anything you do in ``__init__`` that may require
+    ``django.conf.settings`` or Django models there is a good chance it
+    won't work. Use the ``post_setup`` method for that instead.
+
 Alternatives
 ------------