gevent streamer thingy

gistfile1.txt

#!/usr/bin/env python

import gevent.monkey
gevent.monkey.patch_all()

import gevent
import random
import time

from gevent.event import Event
from collections import deque

_evt_set = Event()
_evt_clr = Event()
_dq = deque()

WINDOW = 300  # seconds to keep old data, could use number of samples too

def getMeasurement():
    return random.random()

def measureForever():
    while True:
        # trim old values
        ts = time.time() - WINDOW
        while _dq and _dq[0][0] < ts:
            _dq.popleft()

        # append new value
        data = getMeasurement()
        _dq.append((time.time(), data))

        # wake watchers
        _evt_clr.clear()
        _evt_set.set()

        # take a break
        time.sleep(5)

        # reset
        _evt_set.clear()
        _evt_clr.set()
        
def measurement_sse(id):
    while True:
        _evt_set.wait()
        # just observe the last value in the deque...
        print 'Got:', id, _dq[-1]
        _evt_clr.wait()

gm = gevent.spawn(measureForever)
ga = gevent.spawn(measurement_sse, 'a')
gb = gevent.spawn(measurement_sse, 'b')
gc = gevent.spawn(measurement_sse, 'c')

gevent.joinall([gm, ga, gb, gc])