muddle/core/apps/plugins.py

   1 import inspect
   2
   3 from django.conf import settings
   4
   5 from muddle.util import path_to_class
   6
   7
   8 def load_app_plugin(module_name, Klass=None, method=None):
   9     """
  10     Helper method for loading an app plugin.  An app plugin is defined as some
  11     form of plugin that uses a form of registration logic that other apps must
  12     use to register their usage of the plugin.
  13
  14     Some examples built into django:
  15         * models found within models.py
  16         * admin classes within admin.py
  17
  18     @param module_name: module name to load.  This is a string,
  19     @param klass: class type(s) to load.  This may be a single class or a list
  20     of classes.
  21     @param method: method to run passing in each class that is found, or the
  22     module if no classes are specified
  23     """
  24
  25     for app in settings.INSTALLED_APPS:
  26         try:
  27             module = path_to_class('.'.join([app, module_name]))
  28
  29             if Klass is not None:
  30                 assert(callable(method))
  31
  32                 for name in dir(module):
  33                     # run the method for each member
  34                     obj = getattr(module, name)
  35                     if inspect.isclass(obj) and issubclass(obj, (Klass,)):
  36                         method(obj)
  37
  38             elif callable(method):
  39                 # no classes specified, but there was a method. execute the method
  40                 # with the module
  41                 method(module)
  42
  43             else:
  44                 # no class or method, importing the module is enough
  45                 pass
  46         except ImportError:
  47             # not all apps will have the module we are looking for
  48             pass