Celery结合flask完成异步任务与定时任务

Celery 常用于 web 异步任务、定时任务等。
使用 redis 作为 Celery的「消息代理 / 消息中间件」。
这里通过Flask-Mail使用qq邮箱延时发送邮件作为示例

pip install celery
pip install redis
pip install Flask-Mail

1、使用flask发送邮件

使用 Flask-Mail 发送邮件需要进行一下配置，其中QQ邮箱授权码的获取方式如下所述：

app = Flask(__name__)
app.config['SECRET_KEY'] = 'top-secret!'# Flask-Mail configuration
app.config['MAIL_SERVER'] = 'smtp.qq.com'
app.config['MAIL_PORT'] = 465
# 启用/禁用传输安全层加密
app.config['MAIL_USE_TLS'] = False
# 启用/禁用安全套接字层加密
app.config['MAIL_USE_SSL'] = True
app.config['MAIL_USERNAME'] = '我的QQ邮箱@qq.com'
app.config['MAIL_PASSWORD'] = '我的QQ邮箱授权码'
app.config['MAIL_DEFAULT_SENDER'] = '我的QQ邮箱@qq.com'# Celery configuration
app.config['CELERY_BROKER_URL'] = 'redis://localhost:6379/0'
app.config['CELERY_RESULT_BACKEND'] = 'redis://localhost:6379/0'# Initialize extensions
mail = Mail(app)@app.route("/send_mail")
def index11():# sender：发件人    recipients：收件人msg = Message('Hello', sender = app.config['MAIL_DEFAULT_SENDER'], recipients = ['目标邮箱@qq.com'])msg.body = "来自python--flask框架发送的邮件内容~"mail.send(msg)#发送Message类对象的内容return "发送成功"

点进qq邮箱，在设置里面点击账号，向下滚动开启pop3服务获取授权码。

2、延时发送邮件

定义celery任务，与flask基本一样 只是前面多了修饰符@celery.task

@celery.task
def send_async_email(email_data):"""Background task to send an email with Flask-Mail."""msg = Message(email_data['subject'],sender=app.config['MAIL_DEFAULT_SENDER'],recipients=[email_data['to']])msg.body = email_data['body']with app.app_context():mail.send(msg)     

@app.route('/', methods=['GET', 'POST'])
def index():if request.method == 'GET':return render_template('index.html', email=session.get('email', ''))email = request.form['email']session['email'] = email# send the emailemail_data = {'subject': 'Hello from Flask','to': email,'body': '来自python--flask框架延时发送的邮件内容~'}if request.form['submit'] == 'Send':# send right awaysend_async_email.delay(email_data)print('here!--')flash('Sending email to {0}'.format(email))else:# send in one minutesend_async_email.apply_async(args=[email_data], countdown=60)flash('An email will be sent to {0} in one minute'.format(email))return redirect(url_for('index'))

3、生成带有状态信息进度条的异步任务

# bind为True，会传入self给被装饰的方法
@celery.task(bind=True)
def long_task(self):"""带有进度条以及状态报告的 异步任务"""verb = ['正在', '准备', '目前', '处于', '进行']adjective = ['全速', '努力', '默默地', '认真', '快速']noun = ['打开', '启动', '修复', '加载', '检查']message = ''total = random.randint(10, 50)  # 随机取10~50的一个随机数for i in range(total):selectnow = random.random()print(selectnow)# 拼接上面三个lsit  随机的生成一些状态描述if not message or selectnow < 0.25:message = '{0} {1} {2}...'.format(random.choice(verb),random.choice(adjective),random.choice(noun))# 更新Celery任务状态self.update_state(state='PROGRESS',meta={'current': i, 'total': total,'status': message})time.sleep(1)# 返回字典return {'current': 100, 'total': 100, 'status': '任务完成!','result': 42}@app.route('/longtask', methods=['POST'])
def longtask():task = long_task.apply_async()return jsonify({}), 202, {'Location': url_for('taskstatus', task_id=task.id)}@app.route('/status/<task_id>')
def taskstatus(task_id):task = long_task.AsyncResult(task_id)# print(task.state)if task.state == 'PENDING':# PENDING的时候  如果一直PENDING可能是celery没开启response = {'state': task.state,'current': 0,'total': 1,'status': 'Pending...'}elif task.state != 'FAILURE':# 加载的时候response = {'state': task.state,'current': task.info.get('current', 0),'total': task.info.get('total', 1),'status': task.info.get('status', '')}if 'result' in task.info:response['result'] = task.info['result']else:# 报错时候的输出response = {'state': task.state,'current': 1,'total': 1,'status': str(task.info),  # this is the exception raised}return jsonify(response)

4、完整代码

文件结构

--- current--- templates--- index.html--- asyn_001.py

这个是asyn_001.py

import os
import random
import time
from flask import Flask, request, render_template, session, flash, redirect, \url_for, jsonify
from flask_mail import Mail, Message
from celery import Celeryapp = Flask(__name__)
app.config['SECRET_KEY'] = 'top-secret!'# Flask-Mail configuration
app.config['MAIL_SERVER'] = 'smtp.qq.com'
app.config['MAIL_PORT'] = 465
# 启用/禁用传输安全层加密
app.config['MAIL_USE_TLS'] = False
# 启用/禁用安全套接字层加密
app.config['MAIL_USE_SSL'] = True
app.config['MAIL_USERNAME'] = '我的QQ邮箱@qq.com'
app.config['MAIL_PASSWORD'] = '我的QQ邮箱授权码'
app.config['MAIL_DEFAULT_SENDER'] = '我的QQ邮箱@qq.com'# Celery configuration
app.config['CELERY_BROKER_URL'] = 'redis://localhost:6379/0'
app.config['CELERY_RESULT_BACKEND'] = 'redis://localhost:6379/0'# Initialize extensions
mail = Mail(app)@app.route("/send_mail")
def index11():# sender：发件人    recipients：收件人msg = Message('Hello', sender = app.config['MAIL_DEFAULT_SENDER'], recipients = ['目标邮箱@qq.com'])msg.body = "来自python--flask框架发送的邮件内容~"mail.send(msg)#发送Message类对象的内容return "发送成功"# Initialize Celery
celery = Celery(app.name, broker=app.config['CELERY_BROKER_URL'])
celery.conf.update(app.config)@celery.task
def send_async_email(email_data):"""Background task to send an email with Flask-Mail."""msg = Message(email_data['subject'],sender=app.config['MAIL_DEFAULT_SENDER'],recipients=[email_data['to']])msg.body = email_data['body']with app.app_context():mail.send(msg)@app.route('/', methods=['GET', 'POST'])
def index():if request.method == 'GET':return render_template('index.html', email=session.get('email', ''))email = request.form['email']session['email'] = email# send the emailemail_data = {'subject': 'Hello from Flask','to': email,'body': '来自python--flask框架延时发送的邮件内容~'}if request.form['submit'] == 'Send':# send right awaysend_async_email.delay(email_data)print('here!--')flash('Sending email to {0}'.format(email))else:# send in one minutesend_async_email.apply_async(args=[email_data], countdown=60)flash('An email will be sent to {0} in one minute'.format(email))return redirect(url_for('index'))# bind为True，会传入self给被装饰的方法
@celery.task(bind=True)
def long_task(self):"""带有进度条以及状态报告的 异步任务"""verb = ['正在', '准备', '目前', '处于', '进行']adjective = ['全速', '努力', '默默地', '认真', '快速']noun = ['打开', '启动', '修复', '加载', '检查']message = ''total = random.randint(10, 50)  # 随机取10~50的一个随机数for i in range(total):selectnow = random.random()print(selectnow)# 拼接上面三个lsit  随机的生成一些状态描述if not message or selectnow < 0.25:message = '{0} {1} {2}...'.format(random.choice(verb),random.choice(adjective),random.choice(noun))# 更新Celery任务状态self.update_state(state='PROGRESS',meta={'current': i, 'total': total,'status': message})time.sleep(1)# 返回字典return {'current': 100, 'total': 100, 'status': '任务完成!','result': 42}@app.route('/longtask', methods=['POST'])
def longtask():task = long_task.apply_async()return jsonify({}), 202, {'Location': url_for('taskstatus', task_id=task.id)}@app.route('/status/<task_id>')
def taskstatus(task_id):task = long_task.AsyncResult(task_id)# print(task.state)if task.state == 'PENDING':# PENDING的时候  如果一直PENDING可能是celery没开启response = {'state': task.state,'current': 0,'total': 1,'status': 'Pending...'}elif task.state != 'FAILURE':# 加载的时候response = {'state': task.state,'current': task.info.get('current', 0),'total': task.info.get('total', 1),'status': task.info.get('status', '')}if 'result' in task.info:response['result'] = task.info['result']else:# 报错时候的输出response = {'state': task.state,'current': 1,'total': 1,'status': str(task.info),  # this is the exception raised}return jsonify(response)if __name__ == '__main__':app.run(debug=True)

这个是index.html

<html><head><title>Flask + Celery 示例</title><style>.progress {width: 100%;text-align: center;}</style></head><body><h1>Flask + Celery 示例</h1><h2>Example 1: 发送异步邮件</h2>{% for message in get_flashed_messages() %}<p style="color: red;">{{ message }}</p>{% endfor %}<form method="POST"><p>Send test email to: <input type="text" name="email" value="{{ email }}"></p><input type="submit" name="submit" value="Send"><input type="submit" name="submit" value="Send in 1 minute"></form><hr><h2>Example 2: 生成进度条以及状态报告</h2><!--<button οnclick="start_long_task();">Start Long Calculation</button><br><br>--><button id="start-bg-job">Start Long Calculation</button><br><br><div id="progress"></div><script src="//cdnjs.cloudflare.com/ajax/libs/nanobar/0.2.1/nanobar.min.js"></script><script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script><script>function start_long_task() {// add task status elementsdiv = $('<div class="progress"><div></div><div>0%</div><div>...</div><div>&nbsp;</div></div><hr>');$('#progress').append(div);// create a progress barvar nanobar = new Nanobar({bg: '#44f',target: div[0].childNodes[0]});// send ajax POST request to start background job$.ajax({type: 'POST',url: '/longtask',success: function(data, status, request) {status_url = request.getResponseHeader('Location');console.log("status_url", status_url,"nanobar", nanobar, "div[0]", div[0])console.log("data", data)update_progress(status_url, nanobar, div[0]);},error: function() {alert('Unexpected error');}});}function update_progress(status_url, nanobar, status_div) {// send GET request to status URL$.getJSON(status_url, function(data) {// update UIpercent = parseInt(data['current'] * 100 / data['total']);nanobar.go(percent);$(status_div.childNodes[1]).text(percent + '%');$(status_div.childNodes[2]).text(data['status']);if (data['state'] != 'PENDING' && data['state'] != 'PROGRESS') {if ('result' in data) {// show result$(status_div.childNodes[3]).text('Result: ' + data['result']);}else {// something unexpected happened$(status_div.childNodes[3]).text('Result: ' + data['state']);}}else {// rerun in 2 secondssetTimeout(function() {update_progress(status_url, nanobar, status_div);}, 2000);}});}$(function() {$('#start-bg-job').click(start_long_task);});</script></body>
</html>

5、启动任务

终端cd到current文件夹所在目录

启动asyn_001程序，即可观察到异步任务的执行。

参考1 Celery实现异步任务和定时任务的简单示例
参考2 Using Celery with Flask