I’ve tried reading through questions about sibling imports and even the package documentation, but I’ve yet to find an answer.
With the following structure:
├── LICENSE.md ├── README.md ├── api │ ├── __init__.py │ ├── api.py │ └── api_key.py ├── examples │ ├── __init__.py │ ├── example_one.py │ └── example_two.py └── tests │ ├── __init__.py │ └── test_one.py
How can the scripts in the examples
and tests
directories import from the
api
module and be run from the commandline?
Also, I’d like to avoid the ugly sys.path.insert
hack for every file. Surely
this can be done in Python, right?
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Answer
Seven years after
Since I wrote the answer below, modifying sys.path
is still a quick-and-dirty trick that works well for private scripts, but there has been several improvements
- Installing the package (in a virtualenv or not) will give you what you want, though I would suggest using pip to do it rather than using setuptools directly (and using
setup.cfg
to store the metadata) - Using the
-m
flag and running as a package works too (but will turn out a bit awkward if you want to convert your working directory into an installable package). - For the tests, specifically, pytest is able to find the api package in this situation and takes care of the
sys.path
hacks for you
So it really depends on what you want to do. In your case, though, since it seems that your goal is to make a proper package at some point, installing through pip -e
is probably your best bet, even if it is not perfect yet.
Old answer
As already stated elsewhere, the awful truth is that you have to do ugly hacks to allow imports from siblings modules or parents package from a __main__
module. The issue is detailed in PEP 366. PEP 3122 attempted to handle imports in a more rational way but Guido has rejected it one the account of
The only use case seems to be running scripts that happen to be living inside a module’s directory, which I’ve always seen as an antipattern.
(here)
Though, I use this pattern on a regular basis with
# Ugly hack to allow absolute import from the root folder # whatever its name is. Please forgive the heresy. if __name__ == "__main__" and __package__ is None: from sys import path from os.path import dirname as dir path.append(dir(path[0])) __package__ = "examples" import api
Here path[0]
is your running script’s parent folder and dir(path[0])
your top level folder.
I have still not been able to use relative imports with this, though, but it does allow absolute imports from the top level (in your example api
‘s parent folder).