Run python script from shell script using crontab-CodePudding

I have a shell script main.sh which runs a python script main.py. When i run the main.sh script manually then the execution is fine (Note: i am running it manually with root user) and the python script works as expected. However when i try the same from crontab which runs the main.sh script every 30 mins then python script is not getting executed.(i have already done chmod u x main.sh to make it executable)

The crontab given below is also of the root user

my crontab file: */30 * * * * /home/opc/python_scripts/main.sh >> /home/opc/cron.log.

my main.sh file:

#!/bin/bash
output=$(sh /home/opc/python_scripts/url.sh)
echo "$output"
searchstring="url is up, login service is up and oc console is up"
if [[ "$output" == *"$searchstring"* ]] ; then
    echo "URL is up"
    sudo python3 /home/opc/python_scripts/main.py >> /home/opc/pyfile.log
else
    echo "URL is Down"
    sudo python3 /home/opc/python_scripts/disable_crr.py
fi

I know that it is entering the first if condition and it is also printing the "URL is up" statement, i have another log file which records this. When i run it manually then i can see that even python script is running properly but with crontab it gets stuck at echo "URL is up" , after that no execution happens

Things i have done to solve this:

i have seen solutions of similar questions like-Calling a python script from shell script cron , Shell Script: Execute a python program from within a shell script, but in all of these questions the user was not able to run the python script from the shell script manually. I am able to run it manually but if i use a cronjob then i am having a problem.
when i ran ls -la in the directory where these scripts are located the ownership of these files was like:

main.sh root root  
main.py opc opc

Also i added #!/usr/bin/env python3 at the top of my python script as i had seen this as a solution in a similiar question but did not work, only manually works, not with crontab.

How do i run it with crontab?

CodePudding user response：

Did you try to remove sudo?

However, since you have to run each 30 minutes you can also considered to:

scheduling directly in python using schedule
using a python library to write your CronTab file
running on a more isolated enviroment using docker and schedule with crontab the docker run
finally, if you have access to it, you can consider also using cronjob on a k8s cluster et similia

CodePudding user response：

You're attempting to execute the script with sudo, but cron can't prompt you for the password. Since this is root's crontab, you shouldn't need to use sudo.

If you must use sudo in cron, you need to designate those commands to be passwordless through /etc/sudoers. Something along these lines should work.

opc ALL=(root) NOPASSWD: /home/opc/python_scripts/main.py