Unexpected functionality working on Subscribing Redis channel in python

Question

I'm new to manipulate connection with Redis server in python. I'm wondering that is there any way to figure out the situation below:

What I'm doing is

There are three mainly step for my program:
1. subscribe channel on Redis
2. Get the message from Redis and convert to custom model(or dict)
3. Sent the custom model to my server using socketio

What I write is

async def subscribeRedisChannel():
    for item in r.subscriber.listen():
        logger.info("[DEBUG]Checkin Result from Redis: {}".format(item))
        if item['type'] == 'message':
            checkInSubject.on_next(item)
            await sio.emit('punchByEquipment', data = keep.value)

Environment

python3
socketio
asyncio
rx
redis

The problem I faced

if I call the subscribeRedisChannel function in my main function, the program will be hang on it. Other program cannot work correctly.

score 0 · Answer 1 · answered Dec 23 '20 at 10:09

For those people who have the same or similar issues.

In this problem, I realize that the mainly issues is using blocking message. At he begin I follow the OLD-VERSION example code to implement the connection mechanism between redis and my program

 for message in p.listen():
     # do something with the message

However, you can directly call get_message() to listen the channel in non-blocking mechanism. For the usage example, you can find it in the test code

 while True:
     message = p.get_message()
     if message:
         # do something with the message
     time.sleep(0.001)  # be nice to the system :)

If you are looking for the specific explanation, check this answer in other thread.

Unexpected functionality working on Subscribing Redis channel in python

1 Answers1