modules/mirror_health/files/mirror-health

   1 #! /usr/bin/python3
   2
   3 import os
   4 import requests
   5 import time
   6 import calendar
   7 import logging
   8 import subprocess
   9 from email.utils import parsedate
  10 logging.basicConfig(level=logging.INFO)
  11
  12 if 'MIRROR_CHECK_HOSTS' in os.environ:
  13     HOSTS = os.environ['MIRROR_CHECK_HOSTS'].split()
  14 else:
  15     HOSTS = open(os.environ['MIRROR_CHECK_HOSTS_FILE']).read().split()
  16
  17 OUTPUT_DIR = "/run/dsa-mirror-health-{}".format(os.environ['MIRROR_CHECK_SERVICE'])
  18 HEALTH_FILE = os.path.join(OUTPUT_DIR, "health")
  19 URL = os.environ['MIRROR_CHECK_URL']
  20 HEALTH_CHECK_URL = os.environ['MIRROR_CHECK_HEALTH_URL']
  21 INTERVAL = int(os.environ.get('MIRROR_CHECK_INTERVAL', '60'))
  22
  23 def retrieve_from_host(host, url):
  24     proxies = {
  25         'http': 'http://{}:80'.format(host),
  26         'https': 'http://{}:443'.format(host),
  27     }
  28     headers = {'User-Agent': 'mirror-health'}
  29     return requests.get(url, headers=headers, timeout=5, proxies=proxies, allow_redirects=False)
  30
  31 def last_modified(response):
  32     lm = 0
  33     if response.status_code == 200 and response.headers.get('last-modified'):
  34         lm = calendar.timegm(parsedate(response.headers['last-modified']))
  35     return lm
  36
  37 def healthy(response):
  38     if response.status_code == 200:
  39         return True
  40     return False
  41
  42 def check_shutdown():
  43     if subprocess.call(['dsa-is-shutdown-scheduled']) == 0:
  44         logging.info("considering myself unhealthy, shutdown scheduled")
  45         return False
  46     return True
  47
  48 def check_uptodate():
  49     latest_ts = 0
  50     for host in HOSTS:
  51         try:
  52             lm = last_modified(retrieve_from_host(host, URL))
  53             logging.debug("lm for host %s: %s", host, lm)
  54             if healthy(retrieve_from_host(host, HEALTH_CHECK_URL)):
  55                 latest_ts = max(latest_ts, lm)
  56         except (requests.exceptions.ProxyError, requests.exceptions.ReadTimeout, requests.exceptions.ConnectTimeout, requests.exceptions.ConnectionError):
  57             pass
  58     try:
  59         local_lm = last_modified(retrieve_from_host('localhost', URL))
  60     except (requests.exceptions.ProxyError, requests.exceptions.ReadTimeout, requests.exceptions.ConnectTimeout, requests.exceptions.ConnectionError):
  61         return False
  62     logging.debug("lm for localhost: %s", local_lm)
  63     if local_lm < latest_ts:
  64         logging.info("considering myself unhealthy my ts=%s latest_ts=%s", local_lm, latest_ts)
  65         return False
  66     return True
  67
  68 while True:
  69     start = time.time()
  70     if check_shutdown() and check_uptodate():
  71         logging.info("considering myself healthy")
  72         open(HEALTH_FILE, 'w').write("OK")
  73     else:
  74         try:
  75             os.remove(HEALTH_FILE)
  76         except OSError:
  77             pass
  78     sleep_time = start + INTERVAL - time.time()
  79     logging.debug("sleeping for %d seconds", sleep_time)
  80     time.sleep(sleep_time)