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 Celery
app = Flask(__name__)
app.config['SECRET_KEY'] = 'top-secret!'
# Flask-Mail configuration
app.config['MAIL_SERVER'] = 'smtp.googlemail.com'
app.config['MAIL_PORT'] = 587
app.config['MAIL_USE_TLS'] = True
app.config['MAIL_USERNAME'] = os.environ.get('MAIL_USERNAME')
app.config['MAIL_PASSWORD'] = os.environ.get('MAIL_PASSWORD')
app.config['MAIL_DEFAULT_SENDER'] = 'flask@example.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)
# 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)
@celery.task(bind=True)
def long_task(self):
"""Background task that runs a long function with progress reports."""
verb = ['Starting up', 'Booting', 'Repairing', 'Loading', 'Checking']
adjective = ['master', 'radiant', 'silent', 'harmonic', 'fast']
noun = ['solar array', 'particle reshaper', 'cosmic ray', 'orbiter', 'bit']
message = ''
total = random.randint(10, 50)
for i in range(total):
if not message or random.random() < 0.25:
message = '{0} {1} {2}...'.format(random.choice(verb),
random.choice(adjective),
random.choice(noun))
self.update_state(state='PROGRESS',
meta={'current': i, 'total': total,
'status': message})
time.sleep(1)
return {'current': 100, 'total': 100, 'status': 'Task completed!',
'result': 42}
@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 email
email_data = {
'subject': 'Hello from Flask',
'to': email,
'body': 'This is a test email sent from a background Celery task.'
}
if request.form['submit'] == 'Send':
# send right away
send_async_email.delay(email_data)
flash('Sending email to {0}'.format(email))
else:
# send in one minute
send_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'))
@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)
if task.state == 'PENDING':
response = {
'state': task.state,
'current': 0,
'total': 1,
'status': 'Pending...'
}
elif task.state != 'FAILURE':
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:
# something went wrong in the background job
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)
