How to check whether or not a python script is up?

Question

I want to make sure my python script is always running, 24/7. It's on a Linux server. If the script crashes I'll restart it via cron.

Is there any way to check whether or not it's running?

Answer 1

Taken from this answer:

A bash script which starts your python script and restarts it if it didn't exit normally :

#!/bin/bash
until script.py; do
    echo "'script.py' exited with code $?. Restarting..." >&2
    sleep 1
done

Then just start the monitor script in background:

nohup script_monitor.sh &

---

Edit for multiple scripts:

Monitor script:

cat script_monitor.sh
#!/bin/bash

until ./script1.py 
do
    echo "'script1.py' exited with code $?. Restarting..." >&2
    sleep 1
done &

until ./script2.py 
do
    echo "'script2.py' exited with code $?. Restarting..." >&2
    sleep 1
done & 

scripts example:

cat script1.py
#!/usr/bin/python
import time
while True:
    print 'script1 running'
    time.sleep(3)

cat script2.py
#!/usr/bin/python
import time
while True:
    print 'script2 running'
    time.sleep(3)

Then start the monitor script:

./script_monitor.sh

This starts one monitor script per python script in the background.

Answer 2

Try this and enter your script name.

ps aux | grep SCRIPT_NAME

Answer 3

• Create a script (say check_process.sh) which will
  • Find the process id for your python script by using ps command. Save it in a variable say pid
  • Create an infinite loop. Inside it, search for your process. If found then sleep for 30 or 60 seconds and check again.
  • If pid not found, then exit the loop and send mail to your mail_id saying that process is not running.

Now call check_process.sh by a nohup so it will run in background continuously.

I implemented it way back and remember it worked fine.

Answer 4

You can use

• runit
• supervisor
• monit
• systemd (i think)

Do not hack this with a script

Answer 5

upstart, on Ubuntu, will monitor your process and restart it if it crashes. I believe systemd will do that too. No need to reinvent this.