python - How do I schedule an interval job with APScheduler?

Question

I'm trying to schedule an interval job with APScheduler (v3.0.0).

I've tried:

from apscheduler.schedulers.blocking import BlockingScheduler
sched = BlockingScheduler()

def my_interval_job():
    print 'Hello World!'
sched.add_job(my_interval_job, 'interval', seconds=5)
sched.start()

and

from apscheduler.schedulers.blocking import BlockingScheduler
sched = BlockingScheduler()

@sched.scheduled_job('interval', id='my_job_id', seconds=5)
def my_interval_job():
    print 'Hello World!'
sched.start()

Either should work according to the docs, but the job never fires...

UPDATE:
It turns out there was something else, environment-related, preventing the task from running. This morning, the task is working fine without any modifications to the code from yesterday.

UPDATE 2:
After further testing, I've found that 'interval' jobs seem to be generally flaky... The above code now works in my dev environment, but not when I deploy to a staging env (I'm using a heroku app for staging). I have other apscheduler 'cron' jobs that work just fine in the staging/production envs.

When I turn on DEBUG logging for the "apscheduler.schedulers" logger, the log indicates that the interval job is added:

Added job "my_cron_job1" to job store "default"
Added job "my_cron_job2" to job store "default"
Added job "my_interval_job" to job store "default"
Scheduler started
Adding job tentatively -- it will be properly scheduled when the scheduler starts
Adding job tentatively -- it will be properly scheduled when the scheduler starts
Looking for jobs to run
Next wakeup is due at 2015-03-24 15:05:00-07:00 (in 254.210542 seconds)

How can the next wakeup be due 254 seconds from now when the interval job is set to 5 seconds??

Answer 1

You need to keep the thread alive. Here is a example of how I used it.

from subprocess import call

import time
import os

from apscheduler.schedulers.background import BackgroundScheduler


def job():
    print("In job")
    call(['python', 'scheduler/main.py'])


if __name__ == '__main__':
    scheduler = BackgroundScheduler()
    scheduler.configure(timezone=utc)
    scheduler.add_job(job, 'interval', seconds=10)
    scheduler.add
    scheduler.start()
    print('Press Ctrl+{0} to exit'.format('Break' if os.name == 'nt' else 'C'))

    try:
        # This is here to simulate application activity (which keeps the main thread alive).
        while True:
            time.sleep(5)
    except (KeyboardInterrupt, SystemExit):
        # Not strictly necessary if daemonic mode is enabled but should be done if possible
        scheduler.shutdown()