Fix cyclic import issues in db2de5b.

Author: aaugustin

debug_toolbar/middleware.py

@@ -8,6 +8,7 @@
 
 from django.conf import settings
 from django.utils.encoding import force_text
+from django.utils.importlib import import_module
 
 from debug_toolbar.toolbar import DebugToolbar
 from debug_toolbar import settings as dt_settings
@@ -38,7 +39,11 @@ class DebugToolbarMiddleware(object):
     debug_toolbars = {}
 
     def process_request(self, request):
-        if not dt_settings.CONFIG['SHOW_TOOLBAR_CALLBACK'](request):
+        func_path = dt_settings.CONFIG['SHOW_TOOLBAR_CALLBACK']
+        # Replace this with import_by_path in Django >= 1.6.
+        mod_path, func_name = func_path.rsplit('.', 1)
+        show_toolbar = getattr(import_module(mod_path), func_name)
+        if not show_toolbar(request):
             return
         response = None
         toolbar = DebugToolbar(request)

debug_toolbar/settings.py

@@ -62,12 +62,7 @@
 
 CONFIG = CONFIG_DEFAULTS.copy()
 CONFIG.update(USER_CONFIG)
-if isinstance(CONFIG['SHOW_TOOLBAR_CALLBACK'], six.string_types):
-    # Replace this with import_by_path in Django >= 1.6.
-    mod_path, func_name = CONFIG['SHOW_TOOLBAR_CALLBACK'].rsplit('.', 1)
-    mod = import_module(mod_path)
-    CONFIG['SHOW_TOOLBAR_CALLBACK'] = getattr(mod, func_name)
-else:
+if not isinstance(CONFIG['SHOW_TOOLBAR_CALLBACK'], six.string_types):
     warnings.warn(
         "SHOW_TOOLBAR_CALLBACK is now a dotted path. Update your "
         "DEBUG_TOOLBAR_CONFIG setting.", DeprecationWarning)