Django中使用Celery的方法步骤_Python

(一)、概述

Celery是一个简单、灵活和可靠的基于多任务的分布式系统，为运营提供用于维护此系统的工具。专注于实时处理的任务队列，同时也支持任务的调度。执行单元为任务(task)，利用多线程这些任务可以被并发的在单个或多个职程(worker)上运行。

Celery通过消息机制通信，通常通过中间人(broker)来分配和调节客户端与职程服务器(worker)之间的通信。客户端发送一条消息，中间人把消息分配给一个职程，最后由职程来负责执行此任务。

Celery可以有多个职程和中间人，这样提高了高可用性和横向的扩展能力

Celery由python语言开发，但是该协议可以用任何语言拉力实现，例如：Django中的Celery、node中的node-celery和php中的celery-php

（二）、Django中使用Celery的流程与配置

导入Celery：pip3 install Celery

在与项目同名的目录下创建celery.py文件，特别注意：项目同名的目录下

复制内容到该文件

修改两处内容

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'proj.settings')中的proj改为项目名
app = Celery('pro')中的pro改为项目名

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									import os

									from celery import Celery

									# set the default Django settings module for the 'celery' program.

									os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'proj.settings')

									app = Celery('pro')

									# 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()

									@app.task(bind=True)

									def debug_task(self):

									  print(f'Request: {self.request!r}')

在与项目同名的目录下的__init__.py文件中添加内容

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									# 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

									__all__ = ('celery_app',)

在settings.py文件中添加配置

CELERY_BROKER_URL：中间人url，可以配置redis或者RabbitMQ
CELERY_RESULT_BACKEND：返回结果的存储地址
CELERY_ACCEPT_CONTENT：接收内容的格式，分为两种：json和msgpack。msgpack比json格式的数据体积更小，传输速度更快。
CELERY_TASK_SERIALIZER：任务载荷的序列化方式-->json
CELERY_TIMEZONE
CELERY_TASK_TRACK_STARTED：是否开启任务跟踪
CELERY_TASK_TIME_LIMIT：任务超时限制

				?

									# Celery配置

									CELERY_BROKER_URL = env("CELERY_BROKER_URL")

									CELERY_RESULT_BACKEND = env("CELERY_RESULT_BACKEND")

									CELERY_ACCEPT_CONTENT = ["json", "msgpack"]

									CELERY_TASK_SERIALIZER = "json"

									CELERY_TIMEZONE = "Asia/Shanghai"

									CELERY_TASK_TRACK_STARTED = True

									CELERY_TASK_TIME_LIMIT = 30 * 60

在app下创建tasks.py文件，创建发送消息功能，任务方法必须添加装饰器：@shared_task

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									from rest_framework.response import Response

									from rest_framework.generics import GenericAPIView

									from time import sleep

									from celery import shared_task

									class TestView3(GenericAPIView):

									  @classmethod

									  @shared_task

									  def sleep(self, duration):

									    sleep(duration)

									    return Response("成功", status=200)

创建视图和路由

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									### views.py

									from .tasks import TestView3

									class TestView1(GenericAPIView):

									  def get(self, request):

									    TestView3.sleep(10)

									    return Response("celery实验成功")

									test_view_1 = TestView1.as_view()

									### urls.py

									from django.urls import path

									from .views import (

									  test_view_1

									)

									urlpatterns = [

									  path('celery/', test_view_1, name="test1")

									]

安装redis并启动

启动django项目

使用Celery命令启动Celery服务，命令：celery -A 项目名 worker -l info，如果如下所示则为启动成功.

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									celery@AppledeMacBook-Air.local v5.0.3 (singularity)

									Darwin-20.1.0-x86_64-i386-64bit 2020-12-05 20:52:17

									[config]

									.> app:     drf_email_project:0x7f84a0c4ad68

									.> transport:  redis://127.0.0.1:6379/1%20

									.> results:   redis://127.0.0.1:6379/2

									.> concurrency: 4 (prefork)

									.> task events: OFF (enable -E to monitor tasks in this worker)

									[queues]

									.> celery      exchange=celery(direct) key=celery

									[tasks]

									 . drf_email_project.celery.debug_task

									 . users.tasks.sleep

									[2020-12-05 20:52:18,166: INFO/MainProcess] Connected to redis://127.0.0.1:6379/1%20

									[2020-12-05 20:52:18,179: INFO/MainProcess] mingle: searching for neighbors

									[2020-12-05 20:52:19,212: INFO/MainProcess] mingle: all alone

									[2020-12-05 20:52:19,248: WARNING/MainProcess] /Users/apple/drf-email/lib/python3.7/site-packages/celery/fixups/django.py:204: UserWarning: Using settings.DEBUG leads to a memory

									      leak, never use this setting in production environments!

									 leak, never use this setting in production environments!''')

									[2020-12-05 20:52:19,249: INFO/MainProces