django开发-使用celery搭建分布式(多节点)任务队列

摘要：今天介绍一下如何在项目中使用搭建一个有两个节点的任务队列一个主节点一个子节点主节点发布任务，子节点收到任务并执行。

今天介绍一下如何在django项目中使用celery搭建一个有两个节点的任务队列(一个主节点一个子节点；主节点发布任务，子节点收到任务并执行。搭建3个或者以上的节点就类似了)，使用到了celery,rabbitmq。这里不会多带带介绍celery和rabbitmq中的知识了。

1.项目基础环境：
两个ubuntu18.04虚拟机、python3.6.5、django2.0.4、celery3.1.26post2

2.主节点django项目结构：

3.settings.py中关于celery的配置：

import djcelery
# 此处的Queue和Exchange都涉及到RabbitMQ中的概念，这里不做介绍
from kombu import Queue, Exchange
djcelery.setup_loader()
BROKER_URL = "amqp://test:test@192.168.43.6:5672/testhost"
CELERY_RESULT_BACKEND = "amqp://test:test@192.168.43.6:5672/testhost"

CELERY_TASK_RESULT_EXPIRES=3600
CELERY_TASK_SERIALIZER="json"
CELERY_RESULT_SERIALIZER="json"
# CELERY_ACCEPT_CONTENT = ["json", "pickle", "msgpack", "yaml"]

CELERY_DEFAULT_EXCHANGE = "train"
CELERY_DEFAULT_EXCHANGE_TYPE = "direct"

CELERY_IMPORTS = ("proj.celery1.tasks", )

CELERY_QUEUES = (
  Queue("train", routing_key="train"),
  Queue("predict", routing_key="predict"),
)

4.celery.py中的配置：

# coding:utf8
from __future__ import absolute_import

import os

from celery import Celery
from django.conf import settings

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

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

app = Celery("proj")

# Using a string here means the worker will not have to
# pickle the object when using Windows.
app.config_from_object("django.conf:settings")
# app.autodiscover_tasks(lambda: settings.INSTALLED_APPS)
app.autodiscover_tasks(settings.INSTALLED_APPS)


@app.task(bind=True)
def debug_task(self):
    print("Request: {0!r}".format(self.request))

5.proj/init.py中的配置：

from __future__ import absolute_import
from .celery import app as celery_app

6.celery1/tasks.py：（主节点中的任务不会执行，只执行子节点中的任务）

from __future__ import absolute_import
from celery import task


@task
def do_train(x, y):
    return x + y

7.celery1/views.py：

from .tasks import do_train
class Test1View(APIView):
    def get(self, request):
        try:
            # 这里的queue和routing_key也涉及到RabiitMQ中的知识
            # 关键，在这里控制向哪个queue中发送任务，子节点通过这个执行对应queue中的任务
            ret = do_train.apply_async(args=[4, 2], queue="train", routing_key="train")
            # 获取结果
            data = ret.get()
        except Exception as e:
            return Response(dict(msg=str(e), code=10001))
        return Response(dict(msg="OK", code=10000, data=data))

8.子节点目录结构：

9.子节点中celery1/celery.py：

from __future__ import absolute_import
from celery import Celery
CELERY_IMPORTS = ("celery1.tasks", )
app = Celery("myapp",
             # 此处涉及到RabbitMQ的知识，RabbitMQ是对应主节点上的
             broker="amqp://test:test@192.168.43.6:5672/testhost",
             backend="amqp://test:test@192.168.43.6:5672/testhost",
             include=["celery1.tasks"])

app.config_from_object("celery1.config")

if __name__ == "__main__":
  app.start()

10.子节点中celery1/config.py：

from __future__ import absolute_import
from kombu import Queue,Exchange
from datetime import timedelta

CELERY_TASK_RESULT_EXPIRES=3600
CELERY_TASK_SERIALIZER="json"
CELERY_RESULT_SERIALIZER="json"
CELERY_ACCEPT_CONTENT = ["json","pickle","msgpack","yaml"]

CELERY_DEFAULT_EXCHANGE = "train"
# exchange type可以看RabbitMQ中的相关内容
CELERY_DEFAULT_EXCHANGE_TYPE = "direct"

CELERT_QUEUES =  (
  Queue("train",exchange="train",routing_key="train"),
)

11.子节点celery1/tasks.py：(这个是要真正执行的task，每个节点可以不同)

from __future__ import absolute_import
from celery1.celery import app


import time
from celery import task


@task
def do_train(x, y):
    """
    训练
    :param data:
    :return:
    """
    time.sleep(3)
    return dict(data=str(x+y),msg="train")

12.启动子节点中的celery:
celery1是项目，-Q train表示从train这个queue中接收任务

celery -A celery1 worker -l info -Q train

13.启动主节点中的django项目:

python manage.py runserver

14.使用Postman请求对应的view

请求url：http://127.0.0.1:8000/api/v1/celery1/test/
返回的结果是:
{
    "msg": "OK",
    "code": 10000,
    "data": {
        "data": "6",
        "msg": "train"
    }
}

15.遇到的问题：
1）celery队列报错: AttributeError: ‘str’ object has no attribute ‘items’
解决：将redis库从3.0回退到了2.10，pip install redis==2.10
解决方法参考链接：https://stackoverflow.com/que...

今天就说到这里，如有疑问，欢迎交流。