Access data in package subdirectory

Question

I am writing a python package with modules that need to open data files in a ./data/ subdirectory. Right now I have the paths to the files hardcoded into my classes and functions. I would like to write more robust code that can access the subdirectory regardless of where it is installed on the user's system.

I've tried a variety of methods, but so far I have had no luck. It seems that most of the "current directory" commands return the directory of the system's python interpreter, and not the directory of the module.

This seems like it ought to be a trivial, common problem. Yet I can't seem to figure it out. Part of the problem is that my data files are not .py files, so I can't use import functions and the like.

Any suggestions?

Right now my package directory looks like:

/
__init__.py
module1.py
module2.py
data/   
   data.txt

I am trying to access data.txt from module*.py!

Answer 1

The standard way to do this is with setuptools packages and pkg_resources.

You can lay out your package according to the following hierarchy, and configure the package setup file to point it your data resources, as per this link:

http://docs.python.org/distutils/setupscript.html#installing-package-data

You can then re-find and use those files using pkg_resources, as per this link:

http://peak.telecommunity.com/DevCenter/PkgResources#basic-resource-access

import pkg_resources

DATA_PATH = pkg_resources.resource_filename('<package name>', 'data/')
DB_FILE = pkg_resources.resource_filename('<package name>', 'data/sqlite.db')