How to perform periodic task with Flask in Python

For my Flask application, I contemplated using the cron approach described by Pashka in his answer, the schedule library, and APScheduler.

I found APScheduler to be simple and serving the periodic task run purpose, so went ahead with APScheduler.

Example code:

from flask import Flaskfrom apscheduler.schedulers.background import BackgroundSchedulerapp = Flask(__name__)def test_job():    print('I am working...')scheduler = BackgroundScheduler()job = scheduler.add_job(test_job, 'interval', minutes=1)scheduler.start()

You could use cron for simple tasks.

Create a flask view for your task.

# a separate view for periodic task@app.route('/task')def task():    board.read()    board.digital_outputs = board.digital_inputs

Then using cron, download from that url periodically

# cron task to run each minute0-59 * * * * run_task.sh

Where run_task.sh contents are

wget http://localhost/task

Cron is unable to run more frequently than once a minute. If you need higher frequency, (say, each 5 seconds = 12 times per minute), you must do it in tun_task.sh in the following way

# loop 12 times with a delayfor i in 1 2 3 4 5 6 7 8 9 10 11 12do    # download url in background for not to affect delay interval much    wget -b http://localhost/task    sleep 5sdone

No there is not tasks support in Flask, but you can use flask-celery or simply run your function in separate thread(greenlet).