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', port=1337)
    scheduler.stop()

I tried your code, it works, but why is the query_db() called twice in every 5 seconds?

Hi @chadselph, thanks for your code, it works like @CWang24 said, but really, it call the function twice.

edit:

The code is just fine, the code is flawless, what is called twice is the main function if you don't turn off the reloader. More

Thanks

call the function twice, it's because 'debug=True', you can use 'app.run(host='0.0.0.0', debug=False, port=1337)' or 'app.run(host='0.0.0.0', debug=True, port=1337, use_reloader=False)' to solve this problem.

Good,THKS

Good,THKS. But why import Thread，This doesn't seem to use.