Periodic operations

README.md

Periodic Operations

A sched.scheduler wrapper to run continuously as a "service", to queue up one-time operations.

A PeriodicOperation based on native threading.Timer, runs as a "service".

Both can be stopped.

Timer could have been used in lieu of the scheduler, but the latter stands to have more precision.

periodic_operation.py

import sched
import time
import threading


class ThreadedScheduler(sched.sheduler, threading.Thread):
    def __init__(self):
        threading.Thread.__init__(self, daemon=True)
        sched.scheduler.__init__(self)
        self._running = False


    def cancel(self):
        self._running = False


    def run(self):
        # implement Thread.run() specifically
        # this means ThreadedScheduler is NOT a drop-in for sched.scheduler
        while self._running:
            time.sleep(0.1)
            sched.scheduler.run(self)



class PeriodicOperation(threading.Thread):
    def __init__(self, period_sec:int, operation:Callable):
        threading.Thread.__init__(self, daemon=True)
        self._op = operation
        self._period = period_sec
        self._running = False


    def cancel(self):
        self._running = False


    def run(self):
        self._running = True

        while self._running:
            # Every <self._period> seconds, kick off the op in the background
            #  and immediately wait another round again without waiting for the
            #  op to complete (it is on its merry way)
            opt = threading.Thread(target=self._op, daemon=True)
            t = threading.Timer(self._period, opt.start)
            t.start()
            t.join()