Draft site pinger

pingaling.py

import grequests
import redis
import time

BATCH_SIZE = 10
THRESHOLD = 3
SLEEP_TIME = 60

# MANIFEST -[(URL, Check type, check value), ...]
sites = [
    ('http://www.codebynumbers.net', 'status', 200),
    ('http://platform.50onred.com/health', 'content', 'OK')
]

conn = redis.Redis()

def chunks(l, n):
    """ Yield successive n-sized chunks from l. """
    for i in xrange(0, len(l), n):
        yield l[i:i+n]

def check():
    # Check sites in batches
    for batch in chunks(sites, BATCH_SIZE):
    
        # Get urls in parallel
        rs = (grequests.get(url) for (url, check_type, expected) in batch)
    
        # Process responses
        for i, response in enumerate(grequests.map(rs)):
            (url, check_type, expected) = batch[i] 
            check = response.status_code if check_type == 'status' else response.text
            status = conn.get("status:%s" % url)
            if expected != check:
                print "Check failed for %s, got %s:%s expected %s" % (url, check_type, check, expected)
    
                # record failure in storage
                failures = conn.incr("fails:%s" % url)
    
                # if over consecutive fail threshold, notify 
                if status == "up" and failures == THRESHOLD:
                   print "Notify user, consecutive failures reached"
                   # mark site as down, no more notifcations  
                   conn.set("status:%s" % url, "down")
            else:
                print "Check OK for %s, got %s:%s expected %s" % (url, check_type, check, expected)
                # clear failures
                if status == "down":
                   print "Notify user, site back up"
                conn.set("fails:%s" % url, 0)
                conn.set("status:%s" % url, "up")
    

if __name__ == "__main__":
    while True:
        check()
        time.sleep(SLEEP_TIME)