import logging
import requests

from requests.adapters import HTTPAdapter
from requests.packages.urllib3.util.retry import Retry

logging.basicConfig(level=logging.DEBUG)

s = requests.Session()
retries = Retry(total=5, backoff_factor=0.1, status_forcelist=[ 500, 502, 503, 504 ])
s.mount('http://', HTTPAdapter(max_retries=retries))
s.get("http://httpstat.us/503")