Introduction to two methods of using scheduled tasks in Django

This article brings you an introduction to two methods of using scheduled tasks in Django. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

Today we introduce two ways to use scheduled tasks in Django.

Method 1: APScheduler
1) Installation:

pip install apscheduler

2) Use:

from apscheduler.scheduler import Scheduler
from django.core.cache import cache
# 实例化
sched = Scheduler()    

# 每30秒执行一次
@sched.interval_schedule(seconds=30)
def sched_test():
    """
    测试-定时将随机数保存到redis中
    :return:
    """
    seed = "123456789"
    sa = []
    for i in range(4):
        sa.append(random.choice(seed))
    code = ''.join(sa)
    cache.set("test_"+code, code)

3) Start scheduled task

# 启动定时任务
sched.start()

Method 2: django-crontab
1) Installation:

pip install django-crontab

2) Add configuration to INSTALL_APPS
INSTALLED_APPS = (

'django_crontab',

)
3) Write timing function:

在django的app中新建一个test_crontab.py文件，把需要定时执行的代码放进去

    import random

    from django.core.cache import cache

    def test():
        """
        测试-定时将随机数保存到redis中
        :return:
        """
        seed = "123456789"
        sa = []
        for i in range(4):
            sa.append(random.choice(seed))
        code = ''.join(sa)
        cache.set("test_"+code, code)

4) Write scheduled commands
Django has registered a manage.py command for Python modules whose names do not start with an underscore in the management/commands directory under each application in the project. Customize a command as follows: Required Define a Command class that inherits from BaseCommand and implement the handle method.
Write appname/management/commands/test.py file

import random

from django.core.management.base import BaseCommand
from django.core.cache import cache

class Command(BaseCommand):
    """
    自定义命令
    """
    def handle(self, *args, **options):
        """
        自定义命令
        :return:
        """
        seed = "123456789"
        sa = []
        for i in range(4):
            sa.append(random.choice(seed))
        code = ''.join(sa)
        cache.set("test_"+code, code)

After the definition is completed, execute python manage.py test, the handle() function will be executed

5) In settings.py Add configuration in

# 运行定时函数
CRONJOBS = [
    ('*/1 * * * *', 'appname.test_crontab.test','>>/home/python/test_crontab.log')
]

# 运行定时命令
CRONJOBS = [
    ('*/1 * * * *', 'django.core.management.call_command', ['test'], {}, '>> /home/python/test.log'),
]

There are three main parameters above, which respectively represent: scheduled task execution time (interval), scheduled tasks to be executed, appending scheduled task information to the file
For those who are familiar with timing in Linux Students who use task crontab may be very familiar with the syntax of the first parameter above. The above indicates that the code will be executed every 1 minute.

The syntax of the scheduled task crontab in Linux is as follows:

*  *  *  *  * command
分钟(0-59) 小时(0-23) 每个月的哪一天(1-31) 月份(1-12) 周几(0-6) shell脚本或者命令

Example:

0 6 * * * commands >> /tmp/test.log # 每天早上6点执行, 并将信息追加到test.log中
0 */2 * * * commands # 每隔2小时执行一次

Interested friends can study the crontab scheduled task of Linux in depth.

6) Add and start a scheduled task

python manage.py crontab add

Other commands:

python manage.py crontab show: 显示当前的定时任务
python manage.py crontab remove: 删除所有定时任务

That’s it for today’s scheduled task. If there are any errors, please feel free to share and correct me!

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