app.py

from flask import Flask
from flask_peewee.db import Database

app = Flask(__name__)
DATABASE = {
  'name': 'group_int.db',
  'engine': 'peewee.SqliteDatabase',
  'threadlocals': True,
}
app.config['DATABASE'] = DATABASE

db = Database(app)

main.py

from app import app, db
from models import JsapiTicket

@app.route('/')
def index():
    try:
        jsapi_ticket = JsapiTicket.get(JsapiTicket.id == 1)
        return 'The current ticket: %s; Last refreshed at: %s' % (jsapi_ticket.ticket, jsapi_ticket.modified)
    except JsapiTicket.DoesNotExist:
        return 'No ticket now'

application = app.wsgi_app

models.py

from datetime import datetime
from peewee import *
from app import db

class Base(db.Model):
    created = DateTimeField(default=datetime.now)
    modified = DateTimeField(default=datetime.now)

    def save(self, *args, **kwargs):
        self.modified = datetime.now()
        return super(Base, self).save(*args, **kwargs)


class JsapiTicket(Base):
    ticket = CharField(null=True)
    expire = IntegerField(null=True)

    def __unicode__(self):
        return 'ticket content:%s expires in %d seconds' % (self.ticket, self.expire)

scheduled_ticket.py

"""
An sheduler used with flask-peewee,APScheduler and uwsgi.
Run with uwsgi:
    uwsgi --http-socket :4000 --mule=scheduled_ticket.py --wsgi-file=main.py
"""

from datetime import datetime, timedelta
import os

from apscheduler.schedulers.blocking import BlockingScheduler

from models import JsapiTicket

def get_ticket():
    ticket_content = os.urandom(24).encode('hex')
    return ticket_content, 20

def refresh_ticket(jsapi_ticket):
    jsapi_ticket.ticket = os.urandom(24).encode('hex')
    return jsapi_ticket.save()

def populate_ticket(jsapi_ticket):
    ticket_content, expire = get_ticket()
    jsapi_ticket.ticket = ticket_content
    jsapi_ticket.expire = expire
    return True


def get_or_refresh_jsapi_ticket():
    jsapi_ticket, created = JsapiTicket.get_or_create(id=1)
    if created and populate_ticket(jsapi_ticket) and jsapi_ticket.save():
        print('Create ticket %s' % jsapi_ticket)
    elif datetime.now() - timedelta(seconds = jsapi_ticket.expire) > jsapi_ticket.modified:
        print('Ticket %s expired' % jsapi_ticket)
        populate_ticket(jsapi_ticket)
        jsapi_ticket.save()
    else:
        refresh_ticket(jsapi_ticket)
        print('Ticket %s refreshed' % jsapi_ticket)
    return jsapi_ticket


def tick():
    print('Tick! The time is: %s' % datetime.now())


if __name__ == '__main__':
    JsapiTicket.create_table(fail_silently=True)
    scheduler = BlockingScheduler()
    scheduler.add_job(get_or_refresh_jsapi_ticket, 'interval', seconds=5)
    import logging
    logger = logging.getLogger('apscheduler.executors.default')
    logger.setLevel(logging.DEBUG)
    logger.addHandler(logging.StreamHandler())
    print('Press Ctrl+{0} to exit'.format('Break' if os.name == 'nt' else 'C'))
    try:
        scheduler.start()
    except (KeyboardInterrupt, SystemExit):
        pass