How do I get a Cron like scheduler in Python?

python

cron

scheduling

python-library

byNikita Barsukov·Sep 7, 2024

Working with Cron in Python? No sweat, use the schedule library:

import schedule

# Declaring the function task
def task():
    print("I finished my task!")

# Setting up the task to run every hour
schedule.every().hour.do(task)

# How to never miss your favorite TV show again! 
while True:
    schedule.run_pending()

Get it up by running pip install schedule, call your task function (named task()) with schedule.every().hour.do(task) for an hourly schedule. Give life to the scheduler using while True: schedule.run_pending().

Python in a Cron world

Python loves traditional cron expressions

Get your hands on Crontab, a wizard for Cron expressions in Python. It even manages daylight savings time!

from crontab import CronTab

# Make your Python feel at home on a crontab!
my_cron = CronTab(user='username')
job = my_cron.new(command='python3 /path/to/script.py')
job.minute.every(1)

for result in my_cron.run_scheduler():
    print("Ssssh! The cron is busy", result)

Concurrent jobs, in-thread execution: Python's got it all!

Need concurrency? Think no further than a Gevent-based crontab. Or for tasks cooked right within the thread, pycron has got your back.

from pycron import is_now

def job():
    # Time for some digital breakfast at 04:05 every day!
    if is_now('5 4 * * *'):  
        print("Job served!")

while True:
    job()
    time.sleep(60)  # Beauty sleep for the CPU. Don't want it to burn out, do we?

No stepping on toes: Scheduling tasks without overlaps

To prevent your tasks from wearing the same tie to the party, you have to handle overlapping tasks. If you're a fan of pycron, introduce it to time.sleep(). They'll make a cute time-keeping couple, trust me!

Picking the right cron-scheduler in Python

Flexibility over complexity

When it comes to simplicity and reliability, the schedule library is your best companion. Write your tasks, not your worries!

A Cron tool for every need

Timezones giving you a nightmare? Involve Crontab for solving timezone mysteries. Got multiple tasks? Say hello to Gevent or the super cool Celery, the distributed task handler.

The crowd speaks

Votes and acceptance of a library speak a lot about its reliability. So, do your homework before choosing. However, the community's darling, schedule, is quite a star!

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