Redis: Starting a redis server automatically on connection failure

redis_autostart.py

"""
Setup

    >>> connection_pool = redis.ConnectionPool(connection_class=AutoStartConnection)
    >>> client = redis.StrictRedis(connection_pool=connection_pool)

Does it work? It auto starts on first access:

    >>> client.set("answer", "42")
    Redis offline, starting it.
    Redis start successful.
    True
    >>> client.get("answer")
    '42'

Calling shutdown stops it:

    >>> client.shutdown()
    >>> redis.StrictRedis().ping()      # using default connection pool to avoid autostart
    Traceback (most recent call last):
      ...
    ConnectionError: Error 111 connecting to localhost:6379. Connection refused.

It is automatically started on the next request:

    >>> client.get("answer")
    Redis offline, starting it.
    Redis start successful.
    '42'
    >>> client.ping()
    True

Stop it to make this rerunnable:

    >>> client.shutdown()
"""

import os
import time
import redis
import doctest
import subprocess

class AutoStartConnection(redis.Connection):
    # overrides redis.Connection.connect
    def connect(self):
        """connect but start Redis if it is not there"""
        connect = super(AutoStartConnection, self).connect
        try:
            connect()
        except redis.exceptions.ConnectionError:
            print "Redis offline, starting it."
            subprocess.Popen(["redis-server"], stdout=open(os.devnull, "w"), stderr=subprocess.STDOUT)
            time.sleep(1)
            connect()
            print "Redis start successful."


if __name__ == "__main__":
    doctest.testmod()