使用APScheduler3.0.1 实现定时任务

需求是在某一指定的时刻执行操作

网上的建议多为通过调用Scheduler的add_date_job实现

不过APScheduler 3.0.1与之前差异较大， 无法通过上述方法实现

参考 https://apscheduler.readthedocs.org/en/latest/userguide.html APScheduler 3.0.1的userguide 解决问题

from datetime import datetime
import time
import os

from apscheduler.schedulers.background import BackgroundScheduler


def tick():
    print('Tick! The time is: %s' % datetime.now())


if __name__ == '__main__':
    scheduler = BackgroundScheduler()
    scheduler.add_job(tick, 'interval', seconds=3)
    scheduler.start()
    print('Press Ctrl+{0} to exit'.format('Break' if os.name == 'nt' else 'C'))

    try:
        # This is here to simulate application activity (which keeps the main thread alive).
        while True:
            time.sleep(2)
    except (KeyboardInterrupt, SystemExit):
        scheduler.shutdown()  # Not strictly necessary if daemonic mode is enabled but should be done if possible

实例的代码实现每3秒执行一次tick方法，虽然与需求不符，但发现add_interval_job在APScheduler 3.0.1中 已经被

scheduler.add_job(tick, 'interval', seconds=3)

取代。

help(scheduler.add_job)得到

add_job(func, trigger=None, args=None, kwargs=None, id=None, name=None, misfire_grace_time=undefined, coalesce=undefined, max_instances=undefined, next_run_time=undefined, jobstore='default', executor='default', replace_existing=False, **trigger_args)
Adds the given job to the job list and wakes up the scheduler if it’s already running.

Any option that defaults to undefined will be replaced with the corresponding default value when the job is scheduled (which happens when the scheduler is started, or immediately if the scheduler is already running).

The func argument can be given either as a callable object or a textual reference in the package.module:some.object format, where the first half (separated by :) is an importable module and the second half is a reference to the callable object, relative to the module.

The trigger argument can either be:
the alias name of the trigger (e.g. date, interval or cron), in which case any extra keyword arguments to this method are passed on to the trigger’s constructor
an instance of a trigger class

由此可知，第参数为trigger，可取值为 date、interval、cron， **trigger_args为该trigger的构造函数。

通过源码找到DateTrigger 的构造函数

def __init__(self, run_date=None, timezone=None)

所以，只需将指定的时间传入add_job

scheduler.add_job(tick, 'date', run_date='2014-11-11 14:48:00')