Duplicating Startup Jobs

When I add jobs after flask is started (through a req to the /scheduler), it behaves correctly, but somehow I cannot seem to get apscheduler to run only one instance of a job during startup. It creates two of each job regardless of whether I have max instances set to 1. At this point, I’m not sure this is a problem with my configuration or the code itself since this phenomena occurs whether I use gevent or not as either the flask engine or the scheduler.

# construct flask app object
from flask import Flask, request, session, jsonify, url_for, render_template
app = Flask(import_name=__name__)

# initialize logging and debugging
import sys
import logging
app.logger.addHandler(logging.StreamHandler(sys.stdout))
app.logger.setLevel(logging.DEBUG)
app.config['ASSETS_DEBUG'] = False

# construct the landing page
@app.route('/')
def landing_page():
    return jsonify({'status':'ok'}), 200

# construct the catchall for URLs which do not exist
@app.errorhandler(404)
def page_not_found(error):
    return render_template('404.html'), 404

# construct scheduler object (with gevent processor)
from flask_apscheduler import APScheduler
from apscheduler.schedulers.gevent import GeventScheduler
gevent_scheduler = GeventScheduler()
ap_scheduler = APScheduler(scheduler=gevent_scheduler)

# add job to app scheduler
from time import time
scheduler_configs = {
    'SCHEDULER_JOBS': [ {
        'id': 'app.logger.debug.%s' % str(time()),
        'func': 'launch:app.logger.debug',
        'kwargs': { 'msg': 'APScheduler has started.' },
        'misfire_grace_time': 5,
        'max_instances': 1,
        'replace_existing': False,
        'coalesce': True
    } ],
    'SCHEDULER_TIMEZONE': 'UTC',
    'SCHEDULER_VIEWS_ENABLED': True
}
app.config.update(**scheduler_configs)

# attach app to scheduler and start scheduler
ap_scheduler.init_app(app)
ap_scheduler.start()

# initialize test wsgi localhost server with default memory job store
if __name__ == '__main__':
    from gevent.pywsgi import WSGIServer
    http_server = WSGIServer(('0.0.0.0', 5001), app)
    http_server.serve_forever()
    # app.run(host='0.0.0.0', port=5001)

[eayin2]

I use app.run(use_reloader=False) to prevent flask to create two instances of flask_apscheduler.APScheduler. If I omit use_reload=False jobs are also fired twice for me. See: http://stackoverflow.com/a/15491587

[rj919]

Separating the init from the launch did the trick. And… you make a good point about putting all the configs into an init file being better practice (especially for all these self-referential callables). Thanks!