[Question] How to publish without subscriber with historical message?

After some testing with both pub/sub and xadd/xread I have came to a situation where I have realized that if my subscriber is not on, the message will not be recieved whenever I start up the subscriber. e.g. situation

1. You send a message via publish
2. You turn on your subscriber and listen for the channel 10 seconds after you have send the message via publish
3. The message will be lost.

There is two different codes that I have tried e.g.

Sub.py

from walrus import *
import time
from config import configuration

client = Walrus(
    host=configuration.helheim.redis_host,
    port=configuration.helheim.redis_port,
    db=configuration.helheim.redis_database
)

stream = client.Stream('sns')

while True:
    test = stream.read()
    print(test)
    # How to delete after read?
    time.sleep(3)

Pub.py

from walrus import *

from config import configuration

client = Walrus(
    host=configuration.helheim.redis_host,
    port=configuration.helheim.redis_port,
    db=configuration.helheim.redis_database
)

stream = client.Stream('sns')

test = stream.add({"status": "start", "link": "https://www.sneakersnstuff.com/sv/product/49769/salomon-xa-alpine-mid-advanced"})
print(test)

---

Sub.py

    EVENT_LISTENER.subscribe("sns")
    
    while True:
        message = EVENT_LISTENER.get_message()
    
        if message and not message['data'] == 1:
            message = json.loads(message['data'])

Pub.py

    import redis
    
    from config import configuration
    
    client: redis = redis.Redis(
        host=configuration.helheim.redis_host,
        port=configuration.helheim.redis_port,
        db=configuration.helheim.redis_database
    )
    
    channel = "sns"
    client.publish(channel,
                   '{"status": "kill", "store": "sns", "link": "https://www.sneakersnstuff.com/sv/product/49769/salomon-xa-alpine-mid-advanced"}')

and it seems like there is no persist historical messages saved in the redis.

My question is, how am I able to read the messages that I have publish and remove after a read when I have turned on my subcriber?

Hopefully you guys wont me mad at me for asking this question! 😦

[coleifer]

Streams are similar but for your usage I think using lists is the “correct” approach. You’re not using any of the stream-specific functionality, you’ve just implemented a more hacky version of the list push/pop (in my opinion).

[BarryThrill]

Streams are similar but for your usage I think using lists is the “correct” approach. You’re not using any of the stream-specific functionality, you’ve just implemented a more hacky version of the list push/pop (in my opinion).

Indeed and I agree! I appreciate your help and answer! It means alot for me and I wish you a nice day and evening!