Dynamic class loading in Python 2.6: RuntimeWarning: Parent module 'plugins' not found while handling absolute import

Question

I am working on a plugin system where plugin modules are loaded like this:

def load_plugins():
   plugins=glob.glob(\"plugins/*.py\")
   instances=[]
   for         


        

Answer 1

The Python imp documentation has been updated since this was answered. It now addresses this issue specifically in the find_module() method.

This function does not handle hierarchical module names (names containing dots). In order to find P.M, that is, submodule M of package P, use find_module() and load_module() to find and load package P, and then use find_module() with the path argument set to P.__path__. When P itself has a dotted name, apply this recipe recursively.

Note that P.__path__ is already a list when supplying it to find_module(). Also note what the find_module() documentation says about finding packages.

If the module is a package, file is None, pathname is the package path and the last item in the description tuple is PKG_DIRECTORY.

So from the OP's question, to import the plugin without the RuntimeError warnings, follow the directions in the updated Python documentation:

# first find and load the package assuming it is in
# the current working directory, '.'

f, file, desc = imp.find_module('plugins', ['.'])
pkg = imp.load_module('plugins', f, file, desc)

# then find the named plugin module using pkg.__path__
# and load the module using the dotted name

f, file, desc = imp.find_module(name, pkg.__path__)
plugin = imp.load_module('plugins.' + name, f, file, desc)