relative imports with the __import__ function

[Peter Otten]

Chris Colbert wrote:

> I have package tree that looks like this:
> 
> main.py
> package
> ----__init__.py
> ----configuration.ini
> ----server
> --------__init__.py
> --------xmlrpc_server.py
> --------controller.py
> --------reco
> ------------<irrelevant.py's>
> ----segmentation
> --------__init__.py
> --------red_objects.py
> ----<other irrelevant folders>
> 
> 
> main.py launches an instance of xmlrpc_server.py which, in turn,
> imports controller.py.
> controller.py reads configuration.ini to determine which
> module/function to import from the segmentation directory and
> subsequently use.
> 
> that config file specifies the module as 'red_objects' and the
> function as 'segment_red'.
> 
> I am trying to dynamically import that module and func using the
> __import__ statement but keep getting empty module errors.


> I'm assuming i'm missing something fundamental on the import resolution...

After some experimentation it turns out you have to provide some context for 
__import__() to determine the absolute location of the requested module. The 
required bit of information is the current module's __name__ attribute which 
you can provide via the globals parameter:

def import_segmentation(name):
    return getattr(__import__("segmentation." + name, level=2, 
globals=globals()), name)

Peter