py-schedule

Learning task scheduling in Python and Django using APScheduler

Trigger examples

Interval Examples

Interval trigger is used when you want to run a job at fixed intervals. eg every x minutes evey y hours etc Sample use cases include: Run a job every 4 hours

scheduler_job.add_job(function, 'interval', hours=4)

Give the job a bound usng start and end times such that the task is executed every X hours within this time frame

scheduler_job.add_job(function, 'interval', hours=4, start_date='2020-11-11 09:00:00', end_date='2021-01-25 11:00:00'

Run job every 2 weeks. To run the job monthly, set weeks=4

scheduler_job.add_job(function, 'interval', weeks=2)

Cron Examples

Used when you want to run a job periodically. eg run job every 5th minute of every hour run job every tuesday on 5 am run a job every 3rd tuesday of the month Some use cases include:

Schedule a task to run during summer(june to august) and winter(December to february) on every 3rd friday at 2 AM, 3 AM, 4 AM and 5 AM

scheduler_job.add_job(job_function, 'cron', month='6-8,12,1-2', day='3rd fri', hour='2-5')

Schedule task to run every last friday of the month. This can be to pay salaries

scheduler_job.add_job(job_function, 'cron', day='last fri')

Schedule task to run hourly. Can be a data scrapping and analysis function

scheduler_job.add_job(job_function, 'cron', hour='*')

Schedule a system maintenance script that runs hourly on the weekends from 1 AM to 5 AM

scheduler_job.add_job(maintenance_func, 'cron', day_of_week=['sat','sun'],hour=1-5')

Use combined triggers to generate new parameters eg, Run a maintenance function every 2 hours on select days when you know traffic is less on your site.

from apscheduler.triggers.combining import AndTrigger
from apscheduler.triggers.interval import IntervalTrigger
from apscheduler.triggers.cron import CronTrigger


trigger = AndTrigger([IntervalTrigger(hours=3),
                      CronTrigger(day_of_week='sat,sun')])
scheduler.add_job(job_function, trigger)

Schedule a routine task to run every Sunday at 8 AM and every Friday at 1 PM to 3 PM Could be a reminder task for Christians and Muslims to have their devotion

from apscheduler.triggers.combining import OrTrigger
from apscheduler.triggers.cron import CronTrigger
trigger = OrTrigger([CronTrigger(day_of_week='sun', hour=8),
                     CronTrigger(day_of_week='fri', hour='13-15')])
scheduler.add_job(devotion_reminder, trigger)

Run_Date Examples

Used when you want to run a task at a particular date and time

from datetime import datetime
scheduler.add_job(function,'date',run_date=datetime(2020, 12, 3, 10, 31, 0))

SaaS Scenario Example

Take the example of a SaaS. It wishes to be sending newsletters every last friday of the month to its audience The newsletter can be containing round ups for the month. You can also use an OrTrigger to combine and have weekly triggers, eg every friday and monthly triggers eg every last sunday of the month

from apscheduler.triggers.combining import OrTrigger
from apscheduler.triggers.cron import CronTrigger
# single monthly newsletter job
scheduler_job.add_job(news_letter_send, 'cron', month='*')
# every month on specified day
scheduler_job.add_job(news_letter_send, 'cron', day='first mon')
# combine weekly and monthly
trigger = OrTrigger([CronTrigger(day_of_week='fri', hour=8),
                     CronTrigger(day='last fri', hour='7')])
scheduler.add_job(news_letter_send, trigger)

A function to check if your users are due for payment of your SaaS. You would like this to run daily at a time when the traffic is not too much, lets say 1 AM If payment is due the function sends email

scheduler_job.add_job(check_payment_due, 'cron', day='*', hour=1)

A function that sends reminders and an invoice that payment is due. The trigger will be the same, only that this function will be sending the notification when its 2 days to due date and 1 day to due date it sends the invoice.

Monthly routine function that makes payments to vendors n your system. Lets say payments are made weekly on friday at 3 AM

scheduler_job.add_job(disburse_payments_vendors, 'cron',week='*', hour=3)

Make monthly payments to suppliers at 3 AM

scheduler_job.add_job(disburse_payments_suppliers, 'cron',monthly='*', hour=3)

To refine the above tasks, Monthly payments

scheduler_job.add_job(disburse_payments_vendors, 'cron',day='last fri', hour=3)

Weekly payments

scheduler_job.add_job(disburse_payments_vendors, 'cron',day_of_week=['fri'], hour=3)