在django中使用celery

摘要：前言针对高延时任务直接在一次网络请求中处理完毕会导致很不好的体验则可以不阻塞请求后台处理这些任务并且可以使用的进行数据库操作环境其他创建工程此时项目结构如下修改添加修改创建新创

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前言: 针对高延时任务, 直接在一次网络请求中处理完毕会导致很不好的体验, celery则可以不阻塞请求后台处理这些任务, 并且可以使用django的models进行数据库操作.

python models:

celery-4.1.1

redis-2.10.6

django-1.11.7

其他:

redis-3.2.9

macos

python3.6

django-admin startproject dc
cd dc
django-admin startapp main

此时项目结构如下

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dc
|-- __init__.py
|-- main
|   |-- __init__.py
|   |-- admin.py
|   |-- apps.py
|   |-- migrations
|   |   `-- __init__.py
|   |-- models.py
|   |-- tests.py
|   `-- views.py
|-- settings.py
|-- urls.py
`-- wsgi.py

修改settings.py, 添加app

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INSTALLED_APPS = [
    "django.contrib.admin",
    "django.contrib.auth",
    "django.contrib.contenttypes",
    "django.contrib.sessions",
    "django.contrib.messages",
    "django.contrib.staticfiles",
    "dc.main" //new added
]

修改dc/main/models.py, 创建新models

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from django.db import models
# Create your models here.
class Person(models.Model):
    first_name = models.CharField(max_length=30)
    last_name = models.CharField(max_length=30)

创建根访问节点

dc/main/views.py

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from django.shortcuts import render
from django.http import HttpResponse
# Create your views here.
def hello(request):
    return HttpResponse("hello world")

dc/urls.py

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urlpatterns = [
    url(r"^admin/", admin.site.urls),
    url(r"^$", hello) //new added
]

依次执行以下语句, 初始化django各功能模块

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python manage.py migrate
python manage.py makemigrations main
python manage.py sqlmigrate main 0001
python manage.py migrate

接下来python manage.py runserver, 访问http://127.0.0.1:8000 即可看到hello world.

redis是作为celery中间件使用的, 用来存储消息队列.

redis解压后, 直接运行src/redis-server即可启动, 默认端口6379

参考文档

创建dc/celery.py

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#-*- coding:utf-8 -*-
import os
from celery import Celery
# set the default Django settings module for the "celery" program.
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "dc.settings")
app = Celery("dc")
# Using a string here means the worker doesn"t have to serialize
# the configuration object to child processes.
# - namespace="CELERY" means all celery-related configuration keys
#   should have a `CELERY_` prefix.
app.config_from_object("django.conf:settings", namespace="CELERY")
# Load task modules from all registered Django app configs.
app.autodiscover_tasks()

修改 dc/__init__.py

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from .celery import app as celery_app
__all__ = ["celery_app"]

修改 dc/settings.py, 设定 redis URL

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CELERY_BROKER_URL = "redis://127.0.0.1:6379/3"

创建dc/main/tasks.py

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#-*- coding:utf-8 -*-
from celery import shared_task
@shared_task
def test():
    import time
    time.sleep(5)
    from dc.main.models import Person
    person = Person(first_name="smith", last_name="jhon")
    person.save()
    c = Person.objects.count()
    print(f"person count is {c}")

修改dc/main/views.py

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def hello(request):
    from dc.main.tasks import test
    test.delay()
    return HttpResponse("hello world")

启动celery进程

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celery -A dc worker -l info

接下来访问http://127.0.0.1:8000, 即可发现页面立刻返回, 并没有被time阻塞, 查看启动celery的窗口, 即可发现log以及打印的信息, 确定models可以正常使用.

おわり.