Module Scheduler

This module contains functions to execute functions(tasks) at a regular interval.

Scheduled tasks

Scheduled tasks are tasks that are executed at a predefined interval with the function scheduler.add_task(). This interval can be configured in the similar way as cronjobs are configured. A interval description is built up out of 5 fields separated by white spaces that represent a set of times at which to execute the task The function runs when the current date matches the interval description. A interval description looks like this:

# ┌───────────── second (0 - 59)
# │ ┌───────────── minute (0 - 59)
# │ │ ┌───────────── hour (0 - 23)
# │ │ │ ┌───────────── day of the month (1 - 31)
# │ │ │ │ ┌───────────── day of the week (1 - 7) (Monday to Sunday)
# │ │ │ │ │
# │ │ │ │ │
# │ │ │ │ │
# * * * * *

Special characters can be used to select a range or multiple values for a field. The following special characters are allowed.

* Asterisk - The asterisk is used to select all allowed values for that field.
, Comma - The comma defines a list of values. For example 0,14,29,44 in the first field would mean seconds 0, 14, 29, and 44.
- Dash - The dash defines a range of values. For example 5-10 indicates all minutes between 5 and 10, inclusive. (5, 6, 7, 8, 9, 10)

Example intervals
Expression	Meaning
`* * * * *`	Every second
`0 * * * *`	Every minute at hh:mm:00
`2 * * * *`	Every minute at hh:mm:02
`0 0 * * *`	Every hour at hh:00:00
`5 1 * * *`	Every hour at hh:01:05
`0 0 0 * *`	Every day at 00:00:00
`0,29 * * * *`	Every 30 seconds
`0 0,10,20,30,40,50 * * *`	Every 10 minutes
`0 30 9 * 7`	Every sunday at 9:30:00
`0 0 12 1 *`	Every first day of the month at 12:00:00
`0 0 9-17 * 1-6`	Hourly between 9:00:00 and 17:00:00 except for Sunday

Methods

scheduler.schedule_task(func: function, interval: string, name: string) → None

Add a task to the scheduler to execute at a interval.

func The function to execute. Pass the function without calling it (don’t use the round braces). The function should not have any parameters and the definition should be async.

interval The interval string as explained above.

name The name of the task, used for logging.

scheduler.triggered_task(func: function, name, event=None) → Event

Add a task that can be triggered by an event from for example another task. A pre-existing event object can be used to trigger multiple tasks by the same event.

func The function to execute. Pass the function without calling it (don’t use the round braces). The function should not have any parameters and the definition should be async.

name The name of the task, used for logging.

event The event to trigger the task with, a new event object is created if this parmeter is empty.

Return value: The event object used

sheduler.start() → None: Start the scheduler, executing all the added tasks at the specified interval.

scheduler.trigger_event(event: Event) → None

Trigger an event, starting all associated tasks.

event The event object to trigger

scheduler.sleep_between_tasks(pre_sleep: func, post_sleep: func) → None: Enable light sleep in between tasks running. The device will wake-up 200ms before the next scheduled task.

scheduler.sleep(sec: integer) → None: Let the task sleep for x seconds, giving control back to the scheduler.

scheduler.sleep_ms(ms: integer) → None: Let the task sleep for x milliseconds, giving control back to the scheduler.

Examples

The following code has 3 Tasks, 1 that runs every 5 seconds and 2 triggered tasks, that are started by the first task.

import omc048
import scheduler
import micropython
import utime

led = omc048.LED()
event = None

async def flash_red():
    print('led.colour(\'red\') start: {0}'.format(utime.ticks_ms()))
    led.colour('red')
    await scheduler.sleep_ms(700)
    led.off()
    print('led.colour(\'red\') stop: {0}'.format(utime.ticks_ms()))
    global event
    scheduler.trigger_event(event)

async def flash_blue():
    print('led.colour(\'blue\') start: {0}'.format(utime.ticks_ms()))
    led.colour('blue')
    await scheduler.sleep_ms(20)
    led.off()
    print('led.colour(\'blue\') stop: {0}'.format(utime.ticks_ms()))


async def print_something():
    print("fooo")
    await scheduler.sleep_ms(50)
    print("bar")
    micropython.mem_info()


scheduler.schedule_task(flash_red, '0,5,10,15,20,25,30,35,40,45,50,55 * * * *', 'red')
event = scheduler.triggered_task(flash_blue, 'blue')
scheduler.triggered_task(print_something, 'printing', event)

scheduler.start()