flask_debug.py

#!/usr/bin/env python
from __future__ import print_function
from flask import Flask, render_template, Response
import socket
from contextlib import closing
from threading import Thread
from time import sleep
import logging

logger = None

PORT = 4444

app = Flask(__name__)
shared = [None]

def udp_fire():
    """ sender """
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    with closing(sock):
        while True:
            sock.sendto("this is udp", ("127.0.0.1", PORT))
            sleep(0.5)

def recv_mock():
    """ receiver """
    while True:
        yield "this is mock"
        sleep(0.5)

def recv_udp():
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    with closing(sock):
        sock.bind(("0.0.0.0", PORT))
        while True:
            yield sock.recv(14000)

    # while True:
    #     try:
    #         sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    #         with closing(sock):
    #             sock.bind(("0.0.0.0", PORT))
    #             while True:
    #                 yield sock.recv(14000)
    #     except socket.error, e:
    #         if e.errno != 48:
    #             raise
    #         # Address already in use
    #         logger.error(e)
    #         sleep(1)

def prod():
    # switch these two data
    gen = (
        #recv_mock()
        recv_udp()
    )
    while True:
        data = gen.next()
        shared[0] = data
        logger.info("prod(): [{d}]".format(d=shared[0]))

def cons():
    while True:
        data = shared[0]
        logger.info("cons(): [{d}]".format(d=data))
        yield data

consumer = cons()
@app.route('/')
def index():
    return consumer.next()

def start_threads():
    udp_sender = Thread(target=udp_fire)
    udp_sender.daemon = True
    udp_sender.start()

    producer = Thread(target=prod)
    producer.daemon = True
    producer.start()

if __name__ == '__main__':
    logging.basicConfig(
        level=logging.INFO,
        format="%(asctime)s (pid=%(process)d,%(threadName)s) %(levelname)s %(message)s")
    logger = logging.getLogger(__name__)

    use_reloader = True

    import os
    if use_reloader and os.environ.get('WERKZEUG_RUN_MAIN') != 'true':
        # This is a reloader process itself.
        pass
    else:
        start_threads()

    app.run(host='0.0.0.0', debug=True, use_reloader=use_reloader)
    # app.run(host='0.0.0.0') # <- it works well with UDP