[Python] Why does redis report no subscribers to a channel after I subscribe to that channel...

I am trying to send realtime feedback over websockets, and I'm doing that by sending data over redis from a rest-api server to a websocker server (both written in python/django). In the websocket server, I subscribe to a channel named "events" like this:

redis_connection = redis.Redis(
host=settings.REDIS_HOST,
port=settings.REDIS_PORT,
db=settings.REDIS_CACHE_DB,
)
pubsub = redis_connection.pubsub()
pubsub.subscribe(events=process_event)


In the rest-api server, I publish data to the same redis channel like this:

connection.publish("events", json.dumps({"user_email": user.email, "message": message}))


While trying to figure out why no events ever made it to the "process_event" handler, I found that the publish method returns the number of subscribers to a channel, so I updated that line to this:

count = connection.publish("events", json.dumps({"user_email": user.email, "message": message}))
print(f"Published to events channel with {count} subscribers")


The result is always 0, even after the subscription above. I went inside the redis-stack Docker container saw the following when I directly tried to query the subscriber count:

redis-cli


127.0.0.1:6379> PUBSUB NUMSUB events

1. "events"
2. (integer) 0

127.0.0.1:6379>
​

The logs of the redis-stack itself doesn't seem to recognize any subscription or publication. However, if I use the command "redis-cli monitor" I see both show up:

1727460056.950779 [0 172.17.0.1:58210] "CLIENT" "SETINFO" "LIB-NAME" "redis-py" 1727460056.952892 [0 172.17.0.1:58210] "CLIENT" "SETINFO" "LIB-VER" "5.0.8" 1727460056.954072 [1 172.17.0.1:58210] "SELECT" "1"


1727460056.956442 [1 172.17.0.1:58210] "SUBSCRIBE" "events"


1727460122.677189 [0 172.17.0.1:45874] "CLIENT" "SETINFO" "LIB-NAME" "redis-py" 1727460122.678973 [0 172.17.0.1:45874] "CLIENT" "SETINFO" "LIB-VER" "5.0.8" 1727460122.681286 [1 172.17.0.1:45874] "SELECT" "1"


1727460122.683120 [1 172.17.0.1:45874] "PUBLISH" "events" "{"user_email": "admin@domain.com", "message": "Message content"}"
​

After all that, PUBSUB NUMSUB events still gives the same result.

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