celery-定时更新缓存数据
目录
Celery
官方
Celery架构
Celery的架构由三部分组成,消息中间件(message broker)、任务执行单元(worker)和 任务执行结果存储(task result store)组成。
消息中间件
Celery本身不提供消息服务,但是可以方便的和第三方提供的消息中间件集成。包括,RabbitMQ, Redis等等
任务执行单元
Worker是Celery提供的任务执行的单元,worker并发的运行在分布式的系统节点中。
任务结果存储
Task result store用来存储Worker执行的任务的结果,Celery支持以不同方式存储任务的结果,包括AMQP, redis等
使用场景
异步任务:将耗时操作任务提交给Celery去异步执行,比如发送短信/邮件、消息推送、音视频处理等等
定时任务:定时执行某件事情,比如每天数据统计
Celery的安装配置
pip install celery
消息中间件:RabbitMQ/Redis
app=Celery('任务名', broker='xxx', backend='xxx')
Celery执行异步任务
包架构封装
project
├── celery_task # celery包
│ ├── __init__.py # 包文件
│ ├── celery.py # celery连接和配置相关文件,且名字必须交celery.py
│ └── tasks.py # 所有任务函数
├── add_task.py # 添加任务
└── get_result.py # 获取结果
基本使用
celery.py
# 1)创建app + 任务
# 2)启动celery(app)服务:
# 非windows
# 命令:celery worker -A celery_task -l info
# windows:
# pip3 install eventlet
# celery worker -A celery_task -l info -P eventlet
# 3)添加任务:手动添加,要自定义添加任务的脚本,右键执行脚本
# 4)获取结果:手动获取,要自定义获取任务的脚本,右键执行脚本
from celery import Celery
broker = 'redis://127.0.0.1:6379/1'
backend = 'redis://127.0.0.1:6379/2'
app = Celery(broker=broker, backend=backend, include=['celery_task.tasks'])
tasks.py
from .celery import app
import time
@app.task
def add(n, m):
print(n)
print(m)
time.sleep(10)
print('n+m的结果:%s' % (n + m))
return n + m
@app.task
def low(n, m):
print(n)
print(m)
print('n-m的结果:%s' % (n - m))
return n - m
add_task.py
from celery_task import tasks
# 添加立即执行任务
t1 = tasks.add.delay(10, 20)
t2 = tasks.low.delay(100, 50)
print(t1.id)
# 添加延迟任务
from datetime import datetime, timedelta
def eta_second(second):
ctime = datetime.now()
utc_ctime = datetime.utcfromtimestamp(ctime.timestamp())
time_delay = timedelta(seconds=second)
return utc_ctime + time_delay
tasks.low.apply_async(args=(200, 50), eta=eta_second(10))
get_result.py
from celery_task.celery import app
from celery.result import AsyncResult
id = '21325a40-9d32-44b5-a701-9a31cc3c74b5'
if __name__ == '__main__':
async = AsyncResult(id=id, app=app)
if async.successful():
result = async.get()
print(result)
elif async.failed():
print('任务失败')
elif async.status == 'PENDING':
print('任务等待中被执行')
elif async.status == 'RETRY':
print('任务异常后正在重试')
elif async.status == 'STARTED':
print('任务已经开始被执行')
高级使用
celery.py
# 1)创建app + 任务
# 2)启动celery(app)服务:
# 非windows
# 命令:celery worker -A celery_task -l info
# windows:
# pip3 install eventlet
# celery worker -A celery_task -l info -P eventlet
# 3)添加任务:自动添加任务,所以要启动一个添加任务的服务
# 命令:celery beat -A celery_task -l info
# 4)获取结果
from celery import Celery
broker = 'redis://127.0.0.1:6379/1'
backend = 'redis://127.0.0.1:6379/2'
app = Celery(broker=broker, backend=backend, include=['celery_task.tasks'])
# 时区
app.conf.timezone = 'Asia/Shanghai'
# 是否使用UTC
app.conf.enable_utc = False
# 任务的定时配置
from datetime import timedelta
from celery.schedules import crontab
app.conf.beat_schedule = {
'low-task': {
'task': 'celery_task.tasks.low',
'schedule': timedelta(seconds=3),
# 'schedule': crontab(hour=8, day_of_week=1), # 每周一早八点
'args': (300, 150),
}
}
tasks.py
from .celery import app
import time
@app.task
def add(n, m):
print(n)
print(m)
time.sleep(10)
print('n+m的结果:%s' % (n + m))
return n + m
@app.task
def low(n, m):
print(n)
print(m)
print('n-m的结果:%s' % (n - m))
return n - m
get_result.py
from celery_task.celery import app
from celery.result import AsyncResult
id = '21325a40-9d32-44b5-a701-9a31cc3c74b5'
if __name__ == '__main__':
async = AsyncResult(id=id, app=app)
if async.successful():
result = async.get()
print(result)
elif async.failed():
print('任务失败')
elif async.status == 'PENDING':
print('任务等待中被执行')
elif async.status == 'RETRY':
print('任务异常后正在重试')
elif async.status == 'STARTED':
print('任务已经开始被执行')
django中使用
celery.py
# 重点:要将 项目名.settings 所占的文件夹添加到环境变量
# import sys
# sys.path.append(r'项目绝对路径')
# 开启django支持
import os
os.environ.setdefault('DJANGO_SETTINGS_MODULE', '项目名.settings')
import django
django.setup()
# 1)创建app + 任务
# 2)启动celery(app)服务:
# 非windows
# 命令:celery worker -A celery_task -l info
# windows:
# pip3 install eventlet
# celery worker -A celery_task -l info -P eventlet
# 3)添加任务:自动添加任务,所以要启动一个添加任务的服务
# 命令:celery beat -A celery_task -l info
# 4)获取结果
from celery import Celery
broker = 'redis://127.0.0.1:6379/1'
backend = 'redis://127.0.0.1:6379/2'
app = Celery(broker=broker, backend=backend, include=['celery_task.tasks'])
# 时区
app.conf.timezone = 'Asia/Shanghai'
# 是否使用UTC
app.conf.enable_utc = False
# 任务的定时配置
from datetime import timedelta
from celery.schedules import crontab
app.conf.beat_schedule = {
'django-task': {
'task': 'celery_task.tasks.test_django_celery',
'schedule': timedelta(seconds=3),
'args': (),
}
}
tasks.py
from .celery import app
from home.models import Banner
from settings.const import BANNER_COUNT # 轮播图最大显示条数
from home.serializers import BannerModelSerializer
from django.core.cache import cache
@app.task
def update_banner_list():
# 获取最新内容
banner_query = Banner.objects.filter(is_delete=False, is_show=True).order_by('-orders')[:BANNER_COUNT]
# 序列化
banner_data = BannerModelSerializer(banner_query, many=True).data
for banner in banner_data:
banner['image'] = 'http://127.0.0.1:8000' + banner['image']
# 更新缓存
cache.set('banner_list', banner_data)
return True