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About python : Restart-python-script-automatically-even-when-it-crashes-in-Linux

Question Detail

I have a python program that has to be running all the time. If for some reason it was stopped I want to restart it automatically. I thought of having a cron that will run every n number of seconds and check the program is running. My shell script is looks like this:

#!/usr/bin/env bash
CM_COMMAND=`ps aux| grep abc| grep def| grep sudo`
LEN_COMMAND=${#CM_COMMAND}
if[["$LEN_COMMAND" -le "5"]] 
then
    echo "start the python program"
fi
exit

When I run this script I am getting the error: my_prog.sh: line 4: $'if[[118\r -le 5]]\r': command not found'

What is the alternative of doing this and what is the problem with my script?

Question Answer

Maybe this would be more robust?

1) save the PID of your process when you start it with:

{your_python_command} & echo $! >>/{some_folder}/your_app.pid

2) This script will check and restart if it can’t find the PID..

#!/usr/bin/env bash

PID=`cat /{some_folder}/your_app.pid`

if ! ps -p $PID > /dev/null
then
  rm /{some_folder}/your_app.pid
  {your_python_command} & echo $! >>/{some_folder}/your_app.pid
fi

3) To add it to a cronjob:

crontab -e

choose your text editor and add this row at the end of the file:

*/1 * * * * /{your_path}/{your_script_name}

exit and save

(this will run the script every minute, check crontab manual to set your exact interval)

How about making it a service? A very clean solution, in my opinion.

For more information on how to do it, you can read this article.

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