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Comments on Automatically install all packages needed
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Automatically install all packages needed
When running various Python scripts, I often need to do this annoying dance:
$ python script.py
...
ModuleNotFoundError: No module named 'foo'
$ pip install foo
$ python script.py
...
ModuleNotFoundError: No module named 'bar'
$ pip install bar
$ python script.py
...
ModuleNotFoundError: No module named 'baz'
$ pip install baz
$ python script.py
(correct output from script)
Yes, I know this can be solved by creating a requirements.txt file, packaging the script, etc. But I'm asking about cases where that ship has sailed. All I have is a script that optimistically imports stuff.
Python already knows what package it's supposed to be, since it's named in the ModuleNotFoundError. Is there a way to tell Python to react by attempting a pip install on that, rather than raising an exception?
I am aware that:
-
ModuleNotFoundErrormay raise not just for missing packages, but also modules (eg.foo.py) in the same directory. I'm happy with a solution that blindly assumes it's always PyPi packages. -
Some packages use a different name for
pip installandimport. I'm happy with a solution that fails or installs the wrong package in this case. - It is dangerous to blindly install packages from PyPi. I'm okay with the risks.
Post
The best approach is probably to just check the script beforehand, something like the following
grep import script.py
should list all imports and you can then evaluate and install them.
If you really want to automate things you can write a short shell script to loop & install modules for example this one in bash:
#!/usr/bin/env bash
while :;
do
{ STDERR="$( { ${@}; } 2>&1 1>&3 3>&- )"; } 3>&1;
if [[ $? -eq 0 ]]; then
break
else
module=$(printf '%s' "$STDERR" | grep ModuleNotFoundError | cut -d\' -f 2)
pip install $module
fi
done
when saved as install.sh in the current directory can be used as bash install.sh python script.py
If you create a virtual environment with something like python -m venv env; source env/bin/activate (which you should do to not pollute your global packages anyways) before you can generate a requirements.txt with pip freeze > requirements.txt afterwards and save yourself the hassle in future.
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