Redis+Docker+Django - Error 111 Connection Refused - django

Question

I'm trying to use Redis as a broker for Celery for my Django project that uses Docker Compose. I can't figure out what exactly I've done wrong, but despite the fact that the console log messages are telling me that Redis is running and accepting connections (and indeed, when I do docker ps, I can see the container running), I still get an error about the connection being refused. I even did
docker exec -it <redis_container_name> redis-cli
ping
and saw that the response was PONG.
Here are the Celery settings in my settings.py:
BROKER_URL = 'redis://localhost:6379/0'
BROKER_TRANSPORT = 'redis'
CELERY_RESULT_BACKEND = 'redis://localhost:6379/0'
CELERY_ACCEPT_CONTENT = ['application/json']
CELERY_TASK_SERIALIZER = 'json'
CELERY_RESULT_SERIALIZER = 'json'
CELERY_ENABLE_UTC = True
CELERY_TIMEZONE = "UTC"
Here are the Redis container settings in my docker-compose.yml:
redis:
image: redis
ports:
- "6379:6379"
I remembered to link the redis container with my web container as well. I can start up the server just fine, but I get the connection refused error when I try to upload anything to the site. What exactly is going wrong?
EDIT: I remembered to use VBoxManage to port forward such that I can go to my browser and access my site at localhost:8000, so it doesn't seem like I need to use the VM's IP instead of localhost for my settings.py.
EDIT 2: If I replace localhost in the settings with either the IP address of the docker-machine VM or the IP address of the Redis container, then what happens is that I really quickly get a false success message on my website when I upload a file, but then nothing actually gets uploaded. The underlying upload function, insertIntoDatabase(), uses delay.

Answer 1

I just had similar problem due to updating Celery from v3.1 to v4 and according to this tutorial it was needed to change BROKER_URL to CELERY_BROKER_URL in the settings.py
settings.py part
CELERY_BROKER_URL = 'redis://cache:6379/0'
CELERY_RESULT_BACKEND = 'redis://cache:6379/0'
docker-compose.yml part
version: '2'
services:
web:
container_name: django-container
*******
other options
*******
depends_on:
- cache
- db
cache:
container_name: redis-container
restart: always
image: redis:latest

Answer 2

Is Django running in a seperate container that is linked to the Redis container? If so, you should have some environment variables with the Ip and port that Django should use to connect to the Redis container. Set BROKER_URL to use the redis Ip and port env vars and you should be in business. Ditto for RESULT_BACKEND.
Reference docs for the env vars are here: Docker Compose docs
Here's some example code for how we use the automatically added env vars in one of our projects at OfferUp:
BROKER_TRANSPORT = "redis"
_REDIS_LOCATION = 'redis://{}:{}'.format(os.environ.get("REDIS_PORT_6379_TCP_ADDR"), os.environ.get("REDIS_PORT_6379_TCP_PORT"))
BROKER_URL = _REDIS_LOCATION + "/0"
CELERY_RESULT_BACKEND = _REDIS_LOCATION + "/1"