django core task

定时调度的问题

1.前言

最近在项目中做一个定时统计数据的功能，如何做到定时调用统计方法呢？

在网上看了一下，大致有三种方式


1. [编写Django Command ，用cron进行定时调度](http://www.cnblogs.com/linjiqin/p/3965046.html)

2. 第一种方式的升级版实现[django-crontab实现Django定时任务](http://www.zhidaow.com/post/django-crontab)

3. 编写Django Command 然后rq_scheduler定时把任务提交给队列，由worker进行处理

这里我选用的是第三种方式

2.编写Django Command 然后rq_scheduler定时把任务提交给队列，由worker进行处理

工作原理

*Putting a job in the scheduler

*Running a scheduler that will move scheduled jobs into queues when the time comes

*RQ Scheduler comes with a script rqscheduler that runs a scheduler process that polls Redis once every minute and move scheduled jobs to the relevant queues when they need to be executed:

scheduler.schedule(
    scheduled_time=datetime.now(), # Time for first execution, in UTC timezone
    func=func,                     # Function to be queued
    args=[arg1, arg2],             # Arguments passed into function when executed
    kwargs={'foo': 'bar'},         # Keyword arguments passed into function when executed
    interval=60,                   # Time before the function is called again, in seconds
    repeat=10                      # Repeat this number of times (None means repeat forever)
)

##使用方法

###初始化：

In [1]: from analytics.etl import analytics_etl
In [2]: analytics_etl.init()

1. 安装rq_scheduler
   pip install rq_scheduler
2. 编写测试command scheduler_command.py

class Command(BaseCommand):

    help = "process  analytics data"

    def handle(self, *args, **options):
        first_process_datetime=datetime.now()+timedelta(days=1)
        first_process_datetime.replace(hour=1,minute=0,second=0,microsecond=0)
        first_process_datetime=dateformat.local_to_utc(first_process_datetime)
        scheduler.schedule(first_process_datetime,process,interval=interval)

###调用job

python manage.py scheduler_command --settings=local_settings

###启动rqscheduler

rqscheduler执行一次就ＯＫ
python manage.py rqscheduler --settings=local_settings

启动一个rqworker default

启动一个工作者，
python manage.py rqworker default --settings=local_settings

###查看当前有多少job:

import django_rq

scheduler=django_rq.get_scheduler('default')

jobs=scheduler.get_jobs()

###取消job

scheduler.cancel(job)