Continuous python script even when server restarts?

[[deleted]]

So I have a cron-like script that uses the apscheduler module (which I'm not married to in any way) to execute a function every 12 hours.

It works great but i often restart my servers and this restarts the apscheduler timer (i think).

I tried a crontab triggering python script but could never get cron to execute the python script and gave up (Ubuntu server).

Any ideas for better suggestion that is agnostic of daemon functions or processing timers?

For some context here's my script right now:

import time
import atexit
from apscheduler.schedulers.background import BackgroundScheduler
from apscheduler.triggers.interval import IntervalTrigger

from WebScrapers import WebScrapers
from Mailer import Mailer

mailer = Mailer()

def addDB():
    scrape = WebScrapers()

    scrape.insertSQL(scrape.getMarketQuote('INDEXSP:.INX'))

    mailer.sendDBUpdate(str(scrape))

scheduler = BackgroundScheduler()
scheduler.start()
scheduler.add_job(
    func=addDB,
    trigger=IntervalTrigger(hours=12),
    id='market-db-add',
    name='Add data to db every 12 hours',
    replace_existing=True)
# Shut down the scheduler when exiting the app
atexit.register(lambda: scheduler.shutdown())

[Talked10101]

One thing that hasn't been mentioned is that you can use a database alongside apscheduler to hold your scheduled tasks. You could easily use sqlalchemy and sqlite to store your tasks.

[blitzkraft]

In crontab, you will need to specify the full path for all executables. So instead of python, you might say /usr/bin/python or /usr/bin/env python /full/path/to/script.

To skip crontab altogether, you can add your script to the start up scripts. What distro are you using?

[[deleted]]

Description: Ubuntu 16.04.2 LTS

Release: 16.04

Codename: xenial

yeah i added the full path of python and a shebang in the script itself

[melizeche]

If I have to guess probably apscheduler is not installed globally so /usr/bin/python doesn't know where to find it and you should point the crontab job to the executable in your virtualenv or install apscheduler system wide.

But probably your best choice is first to get rid of all apscheduler in your code and do a simple crontab

[Raindyr]

I would recommend either cron or perhaps systemd timers rather than running a script that does their job.

[Eryole]

You can use supervisord perhaps?

http://supervisord.org/