pub subsystem using Redis

On page 349 of the introductory python 3, I write two codes like the one below, but I get an error
What kind of error is this?　　Similar errors appear in programs in parallel processing.
●redis_pub.py

import redis
import random

conn=redis.Redis()
cats=['siamese', 'personal', 'maine conn', 'norwegian forest']
hats=['stovepipe', 'boowler', 'tam-o-shanter', 'fedora']
for msgin range (10):
    cat=random.choice(cats)
    hat=random.choice(hats)
    print('Publish:%swear a%s'%(cat,hat))
    conn.public(cat,hat)

●redis_sub.py

import redis
conn=redis.Redis()

topics=['maine cone', 'personal']
sub=conn.pubsub()
sub.subscribe(topics)
for msg in sub.listen():
    if msg ['type'] == 'message':
        cat=msg ['channel']
        hat=msg ['data']
        print('Subscribe: %s wear a%s'%(cat,hat))

I get this error when I boot from the terminal

$python redis_sub.py
Traceback (most recent call last):
  File"/Users/tadashintaro/anaconda/lib/python 3.6/site-packages/redis/connection.py", line 439, in connect
    sock=self._connect()
  File"/Users/tadashintaro/anaconda/lib/python 3.6/site-packages/redis/connection.py", line 494, in_connect
    raise err
  File"/Users/tadashintaro/anaconda/lib/python 3.6/site-packages/redis/connection.py", line482, in_connect
    socket.connect(socket_address)
ConnectionRefusedError: [Errno61] Connection refused

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File"/Users/tadashintaro/anaconda/lib/python 3.6/site-packages/redis/client.py", line 2165, in_execute
    return command (*args)
  File"/Users/tadashintaro/anaconda/lib/python 3.6/site-packages/redis/connection.py", line 563, in send_command
    self.send_packed_command(self.pack_command(*args))
  File"/Users/tadashintaro/anaconda/lib/python 3.6/site-packages/redis/connection.py", line 538, in send_packaged_command
    self.connect()
  File"/Users/tadashintaro/anaconda/lib/python 3.6/site-packages/redis/connection.py", line 442, in connect
    raise ConnectionError(self._error_message(e))
redis.exception.ConnectionError: Error 61 connecting to localhost: 6379.Connection refused.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File"/Users/tadashintaro/anaconda/lib/python 3.6/site-packages/redis/connection.py", line 439, in connect
    sock=self._connect()
  File"/Users/tadashintaro/anaconda/lib/python 3.6/site-packages/redis/connection.py", line 494, in_connect
    raise err
  File"/Users/tadashintaro/anaconda/lib/python 3.6/site-packages/redis/connection.py", line482, in_connect
    socket.connect(socket_address)
ConnectionRefusedError: [Errno61] Connection refused

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "redis_sub.py", line 6, in <module>
    sub.subscribe(topics)
  File"/Users/tadashintaro/anaconda/lib/python 3.6/site-packages/redis/client.py", line2229, insubscribe
    ret_val = self.execute_command('SUBSCRIBE', *iterkeys(new_channels))
  File"/Users/tadashintaro/anaconda/lib/python 3.6/site-packages/redis/client.py", line 2161, in execute_command
    self._execute(connection, connection.send_command, *args)
  File"/Users/tadashintaro/anaconda/lib/python 3.6/site-packages/redis/client.py", line 2172, in_execute
    connection.connect()
  File"/Users/tadashintaro/anaconda/lib/python 3.6/site-packages/redis/connection.py", line 442, in connect
    raise ConnectionError(self._error_message(e))
redis.exception.ConnectionError: Error 61 connecting to localhost: 6379.Connection refused.

python

2022-09-30 21:26

1 Answers

redis.exception.ConnectionError: Error 61 connecting to localhost: 6379.Connection refused.

localhost:6379 does not appear to be connected.
Is the Redis server running?
The following command shows the state of the redis process:

 psaux | grep redis

If the process is now up, it should look like this:

redis133190.0 2884 1056?Ss10:540:00/usr/bin/redis-server/etc/redis/redis.conf

(It looks like a Mac, so the display may be different.)

2022-09-30 21:26

If you have any answers or tips

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