This is a simple library for running a function or callable every N seconds. It's meant for applications that need to schedule small, self-contined callable(s) on a relatively long, potentially changing period . alive-checks, state snapshots, that sort of thing.

• You want to call something periodically over the lifetime of your application.
• You want to be able to change the time between calls.
• You want or need to avoid the overhead of joining and starting a thread every time. (up to 1/5 of a second according to my sample-size of one machine under no other load)
• The stuff you're going to call isn't going to destroy machines if it's killed abruptly at the end of the application's life.

• You're already using or likely will be using a fleshed-out concurrency framework.
• You have many things you'd like to repeatedly schedule and run.
• Your callables absolutely must execute some cleanup code to avoid disaster on kill.

This is not a library intended for top-level program composition.

pip install recurring

import recurring

def stuff():
    # do stuff ...

seconds_between_stuff = 30

job = recurring.job(stuff, seconds_between_stuff)
job.start()

# ...

seconds_between_stuff = 300000000 # this will be *from when rate is set*, not *from the next scheduled call*
job.rate = seconds_between_stuff

# ...

# stop making calls until start() is called again
job.stop()

# some time later ....
job.start()

# stop making calls permanently
job.terminate()
job.start() # raises RuntimeError
job.rate = 3000 # raises RuntimeError