django-celery动态添加定时任务

├── apps

│   ├── app1

│   │   ├── __init__.py

│   │   └── tasks.py

│   ├── app2

│   │   ├── __init__.py

│   │   └── tasks.py

│   ├── __init__.py

│   ├── tasks.py

├── djtest

│   ├── celery.py

│   ├── __init__.py

│   ├── settings.py

│   ├── urls.py

│   ├── wsgi.py

└── manage.py

import djcelery  ###
djcelery.setup_loader()  ###
CELERY_TIMEZONE=‘Asia/Shanghai‘  #并没有北京时区，与下面TIME_ZONE应该一致
BROKER_URL=‘redis://10.121.84.90:16379/8‘  #任何可用的redis都可以，不一定要在django server运行的主机上
CELERYBEAT_SCHEDULER = ‘djcelery.schedulers.DatabaseScheduler‘  ###
# Application definition
 
INSTALLED_APPS = (
    ‘django.contrib.admin‘,
    ‘django.contrib.auth‘,
    ‘django.contrib.contenttypes‘,
    ‘django.contrib.sessions‘,
    ‘django.contrib.messages‘,
    ‘django.contrib.staticfiles‘,
    ‘djcelery‘,    ###
    ‘apps‘,     ###
)

TIME_ZONE=‘Asia/Shanghai‘  ###

上面代码首先导出djcelery模块，并调用setup_loader方法加载有关配置；注意配置时区，不然默认使用UTC时间会比东八区慢8个小时。其中INSTALLED_APPS末尾添加两项，分别表示添加celery服务和自己定义的apps服务。接下来编写celery.py文件，

#!/bin/python
from __future__ import absolute_import
 
import os
 
from celery import Celery
 
os.environ.setdefault(‘DJANGO_SETTINGS_MODULE‘, ‘djtest.settings‘)
#Specifying the settings here means the celery command line program will know where your Django project is. 
#This statement must always appear before the app instance is created, which is what we do next: 
from django.conf import settings
 
app = Celery(‘djtest‘)
 
app.config_from_object(‘django.conf:settings‘)
#This means that you don’t have to use multiple configuration files, and instead configure Celery directly from the Django settings.
#You can pass the object directly here, but using a string is better since then the worker doesn’t have to serialize the object.

app.autodiscover_tasks(lambda: settings.INSTALLED_APPS)
#With the line above Celery will automatically discover tasks in reusable apps if you define all tasks in a separate tasks.py module.
#The tasks.py should be in dir which is added to INSTALLED_APP in settings.py. 
#So you do not have to manually add the individual modules to the CELERY_IMPORT in settings.py.
 
@app.task(bind=True)
def debug_task(self):
    print(‘Request: {0!r}‘.format(self.request))  #dumps its own request information

然后修改djtest/__init__.py，

#!/bin/python
from __future__ import absolute_import
 
# This will make sure the app is always imported when
# Django starts so that shared_task will use this app.
from .celery import app as celery_app

    接下来编写你希望django去完成的app，本文中要编写的就是在INSTALLED_APPS中注册的apps。在celery.py中设定了对settings.py中INSTALLED_APPS做autodiscover_tasks，本文希望apps中能够接受这样的目录组织：所有的app都可以放到apps下面，而且每个app都有独立的目录，就和上面的app1、app2一样，每个app各自有各自的__init__.py和tasks.py（注意，每个app都需要__init__.py文件，可以是空白的）。但是这样的结构组织在启动时会报错说module apps找不到。然后在apps下增加了一个__init__.py文件，这时报错没了，但是apps下每个app的tasks.py中的任务函数还是无法被django和celery worker找到。

from __future__ import absolute_import
 
from celery import task
 
from celery import shared_task
 
#from celery.task import tasks 
#from celery.task import Task 
 
@task()
#@shared_task
def add(x, y):
    print "%d + %d = %d"%(x,y,x+y)
    return x+y
#class AddClass(Task):
#    def run(x,y):
#        print "%d + %d = %d"%(x,y,x+y)
#        return x+y
#tasks.register(AddClass)
 
@shared_task
def mul(x, y):
    print "%d * %d = %d"%(x,y,x*y)
    return x*y
 
 
@shared_task
def sub(x, y):
    print "%d - %d = %d"%(x,y,x-y)
    return x-y

上面代码中，decorator可以用@task()也可以用@shared_task。然后，同步django数据库，

（二）

    django正式上线后，需要将settings.py中的"DEBUG = True"注释掉免得内存泄漏，同时在下面加上"ALLOWED_HOSTS = [‘10.121.84.90‘]"，使得admin网页可用（10.121.84.90是django server运行的主机ip）。这时候admin网页会比较丑陋而且有些功能不正常，因为非debug模式下django server不会帮忙处理静态文件，解决方案是在启动django server的时候添加--insecure选项（http://stackoverflow.com/questions/5836674/why-does-debug-false-setting-make-my-django-static-files-access-fail ），使用该选项要确定settings.py的INSTALLED_APPS中有‘django.contrib.staticfiles‘。

Configuring the webserver and worker：http://www.syncano.com/configuring-running-django-celery-docker-containers-pt-1/