Hallo Ricardo,
Am 02.11.2017 um 22:31 schrieb Ricardo Wurmus:
> This made me wonder if we could avoid shell wrappers in more cases.
This is an interesting challenge :-)
> If
> the target script is a Python script we could set the environment
> variables right after the Python shebang with Python code. If the
> target script is a shell script we can set environment variables right
> there after the shebang.
Basically thsi would be a good solution IMO. But I'm afraid it might be
complicated to insert the code "right after the […] shebang". For
example Python has "doc-strings" [1], this is: if the first statement of
the script is a string (expression statement), this string is put into
the variable __doc__. So for at least for Python we might need a
language-aware scanner to insert the code at the correct position. We
might need similar tor other languages.
But taking your challenge :-) I had another idea which should work for
all script languages:
The real script's she-bang delegates to the wrapper (instead of
/bin/sh), which execs "interpreter $0". Here is a proof on concept:
....8<------- real.py
#!/tmp/wrapper.sh
print("This is real")
import sys, os
print("sys.path[:2]", sys.path[:2])
print("argumentes:", sys.argv)
print("ppid", os.getppid())
....8<-------
....8<------- wrapper.sh
#!/bin/sh
echo "This is the wrapper"
echo "arguments in wrapper:" "$@"
echo "ppid:" $PPID
export PYTHONPATH=/foo/bar
exec python3 /tmp/real.py "${@:2}" # <- replace first argument by full path
....8<-------
I have to admit that this still adds another script and is less elegant,
but should be easier to implement.
[]1] https://www.python.org/dev/peps/pep-0257/#what-is-a-docstring
--
Regards
Hartmut Goebel
| Hartmut Goebel | h.goe...@crazy-compilers.com |
| www.crazy-compilers.com | compilers which you thought are impossible |
