Python: modules and packaging - why isn't __init__.py file executed before __main__.py?

Question

I have a python program that is entirely contained in a directory with the following structure: ``` myprog/ ├── __init__.py ├── __main__.py ├── moduleone.py └── moduletwo.py ``` I would like to be able to package this and distribute it so that another developer can do `pip install -e /path/to/git/clone/of/myprog` and can then import myprog in his own programs and do cool stuff with it. I would also like to be able to run myprog at the command line as follows: ``` PROMPT> python myprog ``` When I do this, I expect python to execute the `__main__.py` module, which it does. However, this module makes references to some functions that are declared in `__init__.py` and which need to be available both when the program is run at the command line and when it is imported by another program. However, I'm getting the following error: ``` NameError: name 'function_you_referenced_from_init_file' is not defined ``` Do I have to import these functions into `__main__.py` somehow? I tried a simple exa…

Accepted Answer

Do I have to import these functions into `__main__` somehow?

Yes. Only items in `builtins` are available without an import. Something like:

```
from myprog import func1, func2
```

should do the trick.

If you don't have `myprog` installed in the normal python path then you can work around it with something like:

```
import sys
import os
path = os.path.dirname(sys.modules[__name__].__file__)
path = os.path.join(path, '..')
sys.path.insert(0, path)
from myprog import function_you_referenced_from_init_file
```

Which, quite frankly, is horrid.

I would suggest going with MartijnPieters suggestion and put the `-m` on the command line, in which case `__main__.py` can look like:

```
from myprog import function_you_referenced_from_init_file
```

Python: modules and packaging - why isn't init.py file executed before main.py?

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