README.rst

GreenClock

GreenClock is a time-based task scheduler using gevent

With GreenClock, you can: Schedule a task to run every X seconds, daily, weekly, monthly, or at certain times (such as application startup).

GreenClock launches a green thread per task. Therefore every task will be executed in a concurrent manner, without blocking each other.

Status

This module is currently under development.

Features

- A simple to use API for scheduling jobs.
- Lightweight (depending on gevent only)
- Works with Python 3.7+
- Support the following scheduling scenarios:
    + run every X seconds
    + run every hour at specified minute and second
    + run at specified time (hour:minute:second) every day
    + more to come

Installation

This library depends on gevent 1.4+

To install GreenClock from pip:

$ pip install greenclock

You can also install it into your Python application directory

$ pip install --install-option="--prefix=/path/to/python/app" greenclock

To install GreenClock from source:

$ git clone git@github.com:pcdinh/greenclock.git
$ python setup.py install

Usage

from greenclock.utils import Scheduler, every_second, every_hour
from datetime import datetime
import time

def func_1():
    print('Calling func_1() at ' + str(datetime.now()))
    time.sleep(2)
    print('Ended call to func_1() at ' + str(datetime.now()))

def func_2():
    print('Calling func_2() at ' + str(datetime.now()))
    time.sleep(2)
    print('Ended call to func_2() at ' + str(datetime.now()))

if __name__ == "__main__":
    scheduler = Scheduler(logger_name='task_scheduler')
    scheduler.schedule('task_1', every_second(4), func_1)
    scheduler.schedule('task_2', every_second(1), func_2)
    # Run hourly task at 41:00 every day
    scheduler.schedule('task_3', every_hour(minute=41, second=0), func_3)
    # Run daily task at 12:35:00
    scheduler.schedule('task_2', every_hour(hour=12, minute=35, second=0), func_2)
    # To start the scheduled tasks immediately, specify 'once' for `start_at`
    # Other values:
    # * `next_minute`: Wait until the first seconds of the next minute to run
    # * `next_hour`: Wait until the first seconds of the next hour to run
    # * `tomorrow`: Wait until the first seconds of tomorrow to run
    scheduler.run_forever(start_at='once')

To schedule a periodic task or job, you need to specify the following parameters:

• Task name: task_1
• A timer that let the scheduler know how to run a periodic task

# run the task for every 4 seconds
from greenclock.utils import every_second, every_hour
every_second(4)
# run the task every day at 01:10:00
every_hour(hour=1, minute=10, second=0)

• A function or callable object
• Optional parameters to the above function or callable object

scheduler.schedule('task_1', greenclock.every_second(1), func_1, param1, param2, named_param=2)

Scheduler object can run a separate process which never exits if you want it to

scheduler.run_forever(start_at='once')