flask with "cron"-like loop

flaskwithcron.py

from flask import Flask, render_template, jsonify, request
from threading import Timer, Thread
from time import sleep


app = Flask(__name__)

@app.route("/api/<method>")
def api(method):
    data = {
      'foo': 'bar',
      'method': method
    }
    response = jsonify(data)
    response.status_code = 200
    return response


class Scheduler(object):
    def __init__(self, sleep_time, function):
        self.sleep_time = sleep_time
        self.function = function
        self._t = None

    def start(self):
        if self._t is None:
            self._t = Timer(self.sleep_time, self._run)
            self._t.start()
        else:
            raise Exception("this timer is already running")

    def _run(self):
        self.function()
        self._t = Timer(self.sleep_time, self._run)
        self._t.start()

    def stop(self):
        if self._t is not None:
            self._t.cancel()
            self._t = None


def query_db():
    print "IM QUERYING A DB"

if __name__ == "__main__":
    scheduler = Scheduler(5, query_db)
    scheduler.start()
    app.run(host='0.0.0.0', debug=True, port=1337)
    scheduler.stop()

what is called twice is the main function if you don't turn off the reloader.

http://stackoverflow.com/questions/25504149/why-does-running-the-flask-dev-server-run-itself-twice