NamPNQ / greenclock

Python time-based task scheduler using gevent

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 2.7+
- 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 1.0 RC2

    $ pip install cython -e git://github.com/surfly/gevent.git@1.0rc2#egg=gevent

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 [e-mail]:pcdinh/greenclock.git
    $ python setup.py install

Usage

import greenclock
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 = greenclock.Scheduler(logger_name='task_scheduler')
    scheduler.schedule('task_1', greenclock.every_second(4), func_1)
    scheduler.schedule('task_2', greenclock.every_second(1), func_2)
    # Run hourly task at 41:00 every day
    scheduler.schedule('task_3', greenclock.every_hour(minute=41, second=0), func_3)
    # Run daily task at 12:35:00
    scheduler.schedule('task_2', greenclock.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')

Basically 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
        greenclock.every_second(4) 
        # run the task every day at 01:10:00
        greenclock.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')