Received 'can't find '__main__' module in '<packageName>' with python package

Question

I'm trying to release my first Python package in the wild and I was successful in setting it up on PyPi and able to do a pip install. When I try to run the package via the command line ($ python etlTest), I receive the following error:

/usr/bin/python: can't find '__main__' module in 'etlTest'

When I run the code directly from my IDE, it works without issue. I am using Python 2.7 and have __init__.py scripts where required. What do I need to do to get this working?

Answer 1

I can easily replicate your problem, actually even without using your package:

$ python empty
.env/bin/python: can't open file 'empty': [Errno 2] No such file or directory
$ mkdir empty
$ python empty
.env/bin/python: can't find '__main__' module in 'empty'
$ python Empty
.env/bin/python: can't find '__main__' module in 'Empty'

So you are not calling your library at all, you are just giving the Python interpreter a nonexistent script name, which in case there is a like-named directory (case-insensitive even) in the working directory it tries to execute it.

I was able to install your package from PyPi just fine and can import it alright, but there doesn't seem to be any entry point to it, nothing useful is exported at the top level and no executable scripts are added to Python bin:

>>> import etltest
>>> dir(etltest)
['__author__', '__builtins__', '__doc__', '__file__', '__name__', '__package__',
'__path__', '__version__']

Running the etlTest.py directly as suggested in Quickstart from your docs doesn't work either:

$ python .env/lib/python2.7/site-packages/etltest/etlTest.py
2014-07-13 17:19:56,831 - settings - DEBUG - Attempting to load .env/lib/python2.7/site-packages/.etltest-settings.yml
2014-07-13 17:19:56,832 - settings - WARNING - No such file or directory .env/lib/python2.7/site-packages/.etltest-settings.yml
2014-07-13 17:19:56,832 - settings - DEBUG - Attempting to load .env/lib/python2.7/site-packages/.etltest-settings.yml
2014-07-13 17:19:56,832 - settings - WARNING - No such file or directory .env/lib/python2.7/site-packages/.etltest-settings.yml
2014-07-13 17:19:56,832 - settings - WARNING - Could not find settings file in .env/lib/python2.7/site-packages/.etltest-settings.yml,.env/lib/python2.7/site-packages/.etltest-settings.yml. Using defaults where present.
Traceback (most recent call last):
  File ".env/lib/python2.7/site-packages/etltest/etlTest.py", line 73, in <module>
    main(sys.argv[1:])
  File ".env/lib/python2.7/site-packages/etltest/etlTest.py", line 22, in main
    SettingsManager().first_run_test()
  File ".env/lib/python2.7/site-packages/etltest/utilities/settings_manager.py", line 29, in __init__
    self.app_name = etltest_config['app_name']
KeyError: 'app_name'

I'd say your package is not apt for ditribution yet. You might want to clean up some dependencies on your development environment and read upon setuptools entry points to provide proper command line executables along with your package. Also it shouldn't run in debug mode by default if it's not some kind of a testing release.