Organising packages/modules - importing functions from a common.py in a separate directory?

[Victor Hooi]

Hi,

Ok, so I should be using absolute imports, not relative imports.

Hmm, I just tried to use absolute imports, and it can't seem to locate the modules:

In the file "foo_loading/em_load/sync_em.py", I have:

    from common.common_bex import setup_foo_logging

When I try to run that script:

    python sync_em.py

I get:

    ImportError: No module named common.common_foo

I've also tried adding "foo_loading" (the package name):

    from foo_loading.common.common_bex import setup_foo_logging

Same error:

    ImportError: No module named foo_loading.common.bex_common

Any thoughts?

Cheers,
Victor

On Tuesday, 29 October 2013 00:12:58 UTC+11, Jean-Michel Pichavant  wrote:
> ----- Original Message -----
> > Hi,
> > 
> > I have a collection of Python scripts I'm using to load various bits
> > of data into a database.
> > 
> > I'd like to move some of the common functions (e.g. to setup loggers,
> > reading in configuration etc.) into a common file, and import them
> > from there.
> > 
> > I've created empty __init__.py files, and my current directory
> > structure looks something like this:
> > 
> > foo_loading/
> >     __init__.py
> >     common/
> >         common_foo.py
> >     em_load/
> >         __init__.py
> >         config.yaml
> >         sync_em.py
> >     pg_load/
> >         __init__.py
> >         config.yaml
> >         sync_pg.py
> > 
> > So from within the sync_em.py script, I'm trying to import a function
> > from foo_loading/common/common_foo.py.
> > 
> >     from ..common.common_foo import setup_foo_logging
> > 
> > I get the error:
> > 
> >     ValueError: Attempted relative import in non-package
> > 
> > If I change directories to the parent of "foo_loading", then run
> > 
> >     python -m foo_loading.em_load.sync_em sync_em.py
> > 
> > it works. However, this seems a bit roundabout, and I suspect I'm not
> > doing things correctly.
> > 
> > Ideally, I want a user to be able to just run sync_em.py from it's
> > own directory, and have it correctly import the logging/config
> > modules from common_foo.py, and just work.
> > 
> > What is the correct way to achieve this?
> > 
> > Secondly, if I want to move all of the config.yaml files to a common
> > foo_loading/config.yaml, or even foo_loading/config/config.yaml,
> > what is the correct way to access this from within the scripts?
> > Should I just be using "../", or is there a better way?
> > 
> > Cheers,
> > Victor
> 
> Long story short : use absolute imports.
> 
> name properly your module with a distinct name and import that way, even inside your package:
> 
> import foo_loading.common.common_foo
> 
> Names like common, lib, setup are farely prone to collision with other badly referenced import from other modules. One way to solve this is to use a distinct namespace, in other words, prefix every import with the module name.
> 
> cheers,
> 
> JM
> 
> 
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