[SOLVED] [Linux] Write file and change owner?

[Winfried]

Hello,

In a script in Linux, I need to write a text file, and then change its owner. The script will run as a cron job.

The following script doesn't work, without triggering an error.

What's the right way to proceed?

Thank you.

#!/usr/bin/python3
"""
apt install python3-os
E: Unable to locate package python3-os
"""
import os

OUTPUTFILE = "/usr/share/nginx/html/blah.html"

f = open(OUTPUTFILE, 'w', encoding='utf-8')
#stuff here
f.write("blah")
f.close()

#-rw-r--r-- 1 root     root
os.system(f"chown www:www {OUTPUTFILE}")

[menator01]

From w3schools
https://www.w3schools.com/python/ref_os_chown.asp

[Winfried]

Thanks. The file is still owned by root:root :-/

"""
apt install python3-pwd
E: Unable to locate package python3-pwd
apt install python3-grp
E: Unable to locate package python3-grp
"""
import os
import pwd
import grp

uid = pwd.getpwnam("www").pw_uid
gid = grp.getgrnam("www").gr_gid
#print(f"uid:{uid}, gid:{gid}") #OK
os.chown(OUTPUTFILE, uid, gid)

[menator01]

This seems to work. Got it from https://stackoverflow.com/questions/3949...-in-python

import os
import sys

if os.geteuid() != 0:
	os.execvp('sudo', ['sudo', 'python3'] + sys.argv)
	
os.chown('test.txt', 1000,1000)

[Winfried]

Thanks, it does work: -rw-r--r--

Alternatively, is there a simple way to run a Python script as non-root (manually in the console or through cron) so that files it creates are owned by that non-root user?

--
Edit:
root@debian:~# sudo -u www ./script.py
sudo: unable to execute ./script.py: Permission denied

[menator01]

Are you wanting the script executed by the www user?
Could you not login as that user or root then set the permissions for www to execute the script?
Set the crontab for that user to execute the script?

[Winfried]

Ultimately, the script should run through cron, which can indeed run a script as a non-root user. Here, I was experimenting to see how to change a file's owner in Python.

Turns out you only need this to change file ownership:

from pathlib import Path
import shutil

OUTPUTFILE = "/tmp/test"
Path(OUTPUTFILE).touch()
shutil.chown(OUTPUTFILE, "www-data", "www-data")

Thank you.