Monitors a list of websites, providing notifications when something goes wrong.

requirements.txt

ledcontrol>=0.2
twitter

sitemonitor.py

#!/usr/bin/env python

from argparse import ArgumentParser
from logging import basicConfig, getLogger
from time import sleep
from urllib2 import urlopen

from ledcontrol.enumerator import Enumerator
from twitter import OAuth, Twitter


class SiteMonitor(object):
    """
    Monitors a list of websites.
    """

    def __init__(self, args):
        """
        Initializes the monitor.
        """
        self._args = args
        if self._args.led:
            self._led = iter(Enumerator()).next()
            self._led.color = 'black'
        if self._args.twitter:
            self._twitter = Twitter(auth=OAuth(
                consumer_key=self._args.consumer_key,
                consumer_secret=self._args.consumer_secret,
                token=self._args.token,
                token_secret=self._args.token_secret,
            ))
        self._logger = getLogger('sitemon')
        self._fault = False

    def _down(self, website):
        """
        Take action when a website goes down.
        """
        try:
            if self._args.twitter:
                self._twitter.statuses.update(status='%s is down!' % website)
            if self._args.led:
                self._led.pulse('red', count=4, interval=0.5)
                self._led.color = 'red'
        except Exception as e:
            self._logger.critical(e)

    def _up(self):
        """
        Take action when a website comes back up.
        """
        try:
            if self._args.twitter:
                self._twitter.statuses.update(status='All sites are back up.')
            if self._args.led:
                self._led.interpolate('green', 'black', duration=10)
        except Exception as e:
            self._logger.critical(e)

    def run(self):
        """
        Enters a loop that monitors all websites.
        """
        while True:
            self._logger.info('Performing scheduled update...')
            try:
                for website in self._args.websites:
                    urlopen('http://%s' % website).read()
                if self._fault:
                    self._logger.info('All sites are back up')
                    self._up()
                    self._fault = False
            except Exception as e:
                if not self._fault:
                    self._logger.error('%s: %s' % (website, e))
                    self._down(website)
                    self._fault = True
            sleep(self._args.interval)


if __name__ == '__main__':
    basicConfig(format='[%(levelname)s] %(asctime)s - %(message)s')
    parser = ArgumentParser(description='Monitors a list of websites')
    parser.add_argument(
        '--interval',
        metavar='SECONDS',
        type=int,
        default=300,
        help='number of seconds between updates',
    )
    parser.add_argument(
        '--led',
        action='store_true',
        help='cause an LED device to light for errors',
    )
    parser.add_argument(
        '--twitter',
        action='store_true',
        help='post a tweet for errors',
    )
    parser.add_argument('--consumer-key')
    parser.add_argument('--consumer-secret')
    parser.add_argument('--token')
    parser.add_argument('--token-secret')
    parser.add_argument(
        'websites',
        metavar='WEBSITES',
        nargs='+',
        type=str,
        help='list of websites to check',
    )
    SiteMonitor(parser.parse_args()).run()