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詳解配置Django的Celery異步之路踩坑

更新時(shí)間：2018年11月25日 08:39:37 作者：奶牛博客

這篇文章主要介紹了詳解配置Django的Celery異步之路踩坑，分享一下自己遇見(jiàn)的坑，小編覺(jué)得挺不錯(cuò)的，現(xiàn)在分享給大家，也給大家做個(gè)參考。一起跟隨小編過(guò)來(lái)看看吧

人生苦短，我用python。

看到這句話的時(shí)候，感覺(jué)可能確實(shí)是很深得人心，不過(guò)每每想學(xué)學(xué)，就又止步，年紀(jì)大了，感覺(jué)學(xué)什么東西都很慢，很難，精神啊注意力啊思維啊都跟不上。今天奶牛來(lái)分享自己今天踩的一個(gè)坑。

先說(shuō)說(shuō)配置過(guò)程吧，初學(xué)Django，啥都不懂，當(dāng)然，python也很水，啥東西都得現(xiàn)查現(xiàn)用。Django安裝還是很簡(jiǎn)單的。

apt-get install python3
pip3 install django

嗯，就是兩條命令的事兒。

再說(shuō)celery的安裝：

pip3 install celery
pip3 install redis==2.10.6

目前奶牛所在的時(shí)間redis for python的版本是redis-3.0.1，為什么要用2.10.6呢？因?yàn)?.0.1壓根配置就無(wú)法運(yùn)行?。。?/p>

繼續(xù)安裝redis server

apt-get install redis
service redis start

然后就可以按照celery的官方教程走了，放個(gè)URL：http://docs.celeryproject.org/en/latest/django/index.html

python3 manage.py startproject nenew
cd nenew
python3 manage.py startapp nenewapp
touch ./nenew/celery.py
touch ./nenewapp/tasks.py

然后增加nenew/nenew/celery.py內(nèi)容為

from __future__ import absolute_import, unicode_literals
import os
from celery import Celery

# set the default Django settings module for the 'celery' program.
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'nenew.settings')

app = Celery('nenew')

# 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('Request: {0!r}'.format(self.request))

增加nenew/nenew/__init__.py的內(nèi)容

from __future__ import absolute_import, unicode_literals

# 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',)

增加nenew/nenewtest/tasks.py的內(nèi)容

# Create your tasks here
from __future__ import absolute_import, unicode_literals
from celery import shared_task


@shared_task
def add(x, y):
  return x + y


@shared_task
def mul(x, y):
  return x * y


@shared_task
def xsum(numbers):
  return sum(numbers)

在nenew/nenew/settings.py中增加和修改

...

ALLOWED_HOSTS = ['*']
....

INSTALLED_APPS = [
...
  'nenewtest',
]

...

CELERY_BROKER_URL = 'redis://localhost:6379/1'
CELERY_RESULT_BACKEND = ‘redis://localhost:6379/0'

在nenew/nenewtest/views.py中增加或修改為

from django.shortcuts import render
from django.http import HttpResponse
from .tasks import add
# Create your views here.
def nenewtest(request):
  result = add.delay('2','2')
  result.ready()
  return HttpResponse('nenew Django Celery worker run !')

最后把views添加到nenew/nenew/urls.py中

from django.contrib import admin
from django.urls import path
from nenewtest import views

urlpatterns = [
  path('admin/', admin.site.urls),
  path('test/', views.nenewtest),
]

然后在項(xiàng)目目錄nenew執(zhí)行

celery -A nenew worker -l info

這時(shí)候worker啟動(dòng)正常會(huì)顯示：

-------------- <a href="/cdn-cgi/l/email-protection" rel="external nofollow" data-cfemail="2c4f4940495e556c424942495b">[email protected]</a> v4.2.1 (windowlicker)
---- **** -----
--- * *** * -- Linux-4.15.0-39-generic-x86_64-with-Ubuntu-18.04-bionic 2018-11-23 17:31:25
-- * - **** ---
- ** ---------- [config]
- ** ---------- .> app:         nenew:0x7fdc5a155cc0
- ** ---------- .> transport:   redis://localhost:6379/1
- ** ---------- .> results:     redis://localhost:6379/0
- *** --- * --- .> concurrency: 1 (prefork)
-- ******* ---- .> task events: OFF (enable -E to monitor tasks in this worker)
--- ***** -----
-------------- [queues]
                .> celery           exchange=celery(direct) key=celery

這樣類似的信息，然后我們啟動(dòng)項(xiàng)目，這里需要新開(kāi)一個(gè)shell：

python3 manage.py runserver 0:80

這樣我們就可以通過(guò)80端口直接訪問(wèn)我們的web了。地址是http://locahost/test

當(dāng)我們這里訪問(wèn)正常后，在worker界面會(huì)有

[2018-11-23 18:09:19,469: INFO/MainProcess] Received task: nenewtest.tasks.add[35faa0fe-dd48-4f8d-9559-516556a93a40]
[2018-11-23 18:09:19,470: INFO/ForkPoolWorker-1] Task nenewtest.tasks.add[35faa0fe-dd48-4f8d-9559-516556a93a40] succeeded in 0.00031037399821798317s: '22'

如下語(yǔ)句表示執(zhí)行成功，這樣子就表示通過(guò)Django的網(wǎng)頁(yè)我們對(duì)celery任務(wù)的異步執(zhí)行成功。

當(dāng)然，按照我的方法是可以一步成功的，因?yàn)槟膛Ｒ呀?jīng)踩了一整天的坑了，被一個(gè)錯(cuò)誤郁悶得不要不要的。

AttributeError: 'float' object has no attribute 'items'

就是這個(gè)錯(cuò)誤，查遍國(guó)內(nèi)的所有網(wǎng)站都沒(méi)有結(jié)果，然后就去bing的國(guó)際版查，然后發(fā)現(xiàn)果然是有bug在啊，奶牛這一天浪費(fèi)得可真是夠了。

這是celery的一個(gè)issue，在地址https://github.com/celery/celery/issues/5175 ，issue里面提及在2018/11/22日 it's fixed in kombu and celery master。問(wèn)題的根源是celery對(duì)redis3的支持不好，補(bǔ)救方法是