[FIXED] Share a single connection between django requests

Issue

Looking for a reliable way of sharing connection objects in django project, similarly to django database connections.

from django.db import connections
with connections['default'].cursor() as cursor:
    cursor.execute(sql, params)

Not necessarily with the same API but I need a similar way of acquiring redis connection pools which initializes on django server startup, so I could reuse single connection pool from different parts of the project.

Do you have any suggestions or ideas how can I approach this issue ?

Solution

Solution which worked for me was found in django CacheHandler

In this case for building REDIS connection redis-sentinel-url is used.

settings.py - Redis connection string definitions in

REDIS = {
    "default": "redis:///",
    "secondary": "redis+sentinel:///"
}

RedisPoolHandler class implementation similar to django CacheHandler

from threading import local

import redis_sentinel_url
from django.conf import settings
from django.core.cache import InvalidCacheBackendError


class RedisClientHandler:
    """
    A Redis Client Handler to manage access to Redis instances.
    Ensure only one instance of each alias exists per thread.
    """
    def __init__(self):
        self._clients = local()

    def __getitem__(self, alias):
        try:
            return self._redis_clients.caches[alias]
        except AttributeError:
            self._redis_clients.caches = {}
        except KeyError:
            pass

        if alias not in settings.REDIS:
            raise InvalidCacheBackendError(
                "Could not find config for '%s' in settings.REDIS" % alias
            )

        value = settings.REDIS[alias]
        sentinel, redis_pool = redis_sentinel_url.connect(value, client_options={"decode_responses": True})

        self._redis_clients.caches[alias] = redis_pool
        return redis_pool

    def all(self):
        return getattr(self._redis_clients, '_redis_clients', {}).values()


redis_clients = RedisPoolHandler()

Usage example below:

from path.to.classfile import redis_clients

redis_client = redis_clients['default']

Answered By - demonno