app.py

from flask import Flask
from redis import Redis, RedisError

import os
import socket

# Connect to Redis
redis = Redis(host='redis', db=0, socket_connect_timeout=2, socket_timeout=2)

app = Flask(__name__)

@app.route("/")
def hello():
  try:
    visits = redis.incr('counter')
  except RedisError:
    visits = '<i>cannot connect to Redis, counter disabled</i>'

  html = '<h3>Hello {name}!</h3>' \
         '<b>Hostname:</b> {hostname}<br />' \
         '<b>Visits:</b> {visits}'
  return html.format(name=os.getenv('NAME', 'world'),
                     hostname=socket.gethostname(),
                     visits=visits)

if __name__ == '__main__':
  app.run(host='0.0.0.0', port=80)