How to run a Bash script that calls a Python script from any location?

Question

I have a Python script, say myscript.py, that uses relative module imports, ie from .. import module1, where my project layout is as follows:

project
 + outer_module
   - __init__.py
   - module1.py
   + inner_module
     - __init__.py
     - myscript.py
     - myscript.sh

And I have a Bash script, say myscript.sh, which is a wrapper for my python script, shown below:

#!/bin/bash
python -m outer_module.inner_module.myscript $@

This works to execute myscript.py and forwards the arguments to my script as desired, but it only works when I call ./outer_module/inner_module/myscript.sh from within the project directory shown above.

How can I make this script work from anywhere? For example, how can I make this work for a call like bash /root/to/my/project/outer_module/inner_module/myscript.sh?

Here are my attempts:

When executing myscript.sh from anywhere else, I get the error: No module named outer_module.inner_module. Then I tried another approach to execute the bash script from anywhere, by replacing myscript.sh with:

#!/bin/bash
scriptdir=`dirname "$BASH_SOURCE"`
python $scriptdir/myscript.py $@

When I execute myscript.sh as shown above, I get the following:

Traceback (most recent call last):
  File "./inner_module/myscript.py", line 10, in <module>
    from .. import module1
ValueError: Attempted relative import in non-package

Which is due to the relative import on the first line in myscript.py, as mentioned earlier, which is from .. import module1.

Your working directory has to be the directory that outer_module is in, not in outer_module itself; otherwise outer_module isn't a package (hence the exception). (It's hard to be too precise since you seem to have switched names for everything halfway through the question, but if you're inside inner_module, it's the same problem.) — abarnert
– abarnert, Commented Nov 4, 2014 at 23:59
Or, alternatively, you just need to not be in any of those directories, and set PYTHONPATH=<the directory that outer_module is in> before running the script. — abarnert
– abarnert, Commented Nov 5, 2014 at 0:00
Also, if you're normally running the script with -m, better to have your launcher also use -m; there's no reason to try to debug the differences between running it as a -m module vs. running it as a script if you don't actually want any of those differences. — abarnert
– abarnert, Commented Nov 5, 2014 at 0:00
Finally, is there a reason you're not just using setuptools to create a trivial installer? Then you could do an in-place build that would build a wrapper for you to use in your source tree, or a normal install that would put the project into site-packages and build a wrapper for you in your bin or scripts directory, and either way, it takes care of all the mess for you. — abarnert
– abarnert, Commented Nov 5, 2014 at 0:02

Brian Campbell · Accepted Answer · 2014-11-05 00:18:49Z

3

As the error message says:

ValueError: Attempted relative import in non-package

The solution to this is to create a package, and have your script execute with that package in its path.

You already have a package, as you have the __init__.py files in those directories; but you only have that package in your path when you are calling it from the project directory, as you mentioned; that's because . is in your Python path by default.

To fix this, just add the project directory to your Python path, and then invoke it with python -m outer_module.inner_module.myscript:

#!/bin/bash
export PYTHONPATH=$PYTHONPATH:$(dirname "$BASH_SOURCE")/../..
python -m outer_module.inner_module.myscript $@

answered Nov 5, 2014 at 0:18

Brian Campbell

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stonesam92 · Accepted Answer · 2014-11-05 00:16:12Z

2

You need to include the path to the outer module's parent directory in the PYTHONPATH environmental variable, then you can use the same command you used in the first script from anywhere.

The PYTHONPATH is where python searches for any modules you try to import:

#!/bin/bash
export PYTHONPATH=$PYTHONPATH:PATH/TO/MODULE/PARENTDIR
python -m outer_module.inner_module.myscript $@

answered Nov 5, 2014 at 0:16

stonesam92

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