Redis Handling using three connections max for Django Websocket Applications using Pub/Sub

DjangoRedisPubSubSingleton.py

"""
Import RedisSingleton and create the object by doing:
redis_singleton = await RedisSingleton()

That way, you've not only created a new object in memory but also
executed the await in the magic method. This is helpful when you have
wayyy too many Django's and connections become overloaded.

There should now only be three connection for:
PUBSCRIBE x2 and PUBLISH
id=8 addr=[::1]:61841 fd=9 name= age=26 idle=4 flags=P db=0 sub=0 psub=1 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=psubscribe
id=9 addr=[::1]:61842 fd=10 name= age=26 idle=4 flags=P db=0 sub=0 psub=1 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=psubscribe
id=10 addr=[::1]:61843 fd=11 name= age=24 idle=4 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=publish

(Note: if you do CLIENT LIST in the redis cli, then the first conn is most
likely your cli conn to Redis, not Django instance's. Notice the ids).
Tested on 3 different users.
"""
import aioredis


class RedisSingleton(object):
    # docker-compose -f local.yml run --rm redis redis-cli -u redis://redis:6379/
    _instance = None
    _initial = False
    redis = 0
    ch = 0

    async def initialize_redis(self):
        redis = await aioredis.create_redis_pool('redis://localhost:6379')
        assert type(redis) is not None, "Couldn't connect to Redis from RedisSingleton"
        ch, = await redis.psubscribe('chat_*')
        return redis, ch

    def __await__(self):
        if not self._initial:
            self.redis, self.ch = yield from self.initialize_redis().__await__()
            self._initial = True
        return self._instance

    def __new__(cls):
        if not cls._instance:
            print('Creating RedisSingleton')
            cls._instance = super(RedisSingleton, cls).__new__(cls)
        return cls._instance