How to execute get command in redis cluster mode using python?

Question

I want to perform the following scenario on redis using python.

Using command line: 1) redis-cli -c 2) redis_prompt >> get some_string

I tried using redis and rediscluster modules, but with no luck. Below are the codes that i tried:

1)

r = redis.Redis(host='123.123.123.123', port=6379, db=0)
r.get('some srting')

Got the following error:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Python27\lib\site-packages\redis\client.py", line 880, in get
    return self.execute_command('GET', name)
  File "C:\Python27\lib\site-packages\redis\client.py", line 573, in execute_command
    return self.parse_response(connection, command_name, **options)
  File "C:\Python27\lib\site-packages\redis\client.py", line 585, in parse_response
    response = connection.read_response()
  File "C:\Python27\lib\site-packages\redis\connection.py", line 582, in read_response
    raise response
redis.exceptions.ResponseError: MOVED 9442 172.16.176.36:6380

2)

from rediscluster import StrictRedisCluster
startup_nodes = [{"host": "123.123.123.123", "port": "7000"}]
rc_readonly = StrictRedisCluster(startup_nodes=startup_nodes, decode_responses=True, readonly_mode=True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Python27\lib\site-packages\rediscluster\client.py", line 181, in __init__
    **kwargs
  File "C:\Python27\lib\site-packages\rediscluster\connection.py", line 353, in __init__
    **connection_kwargs)
  File "C:\Python27\lib\site-packages\rediscluster\connection.py", line 141, in __init__
    self.nodes.initialize()
  File "C:\Python27\lib\site-packages\rediscluster\nodemanager.py", line 240, in initialize
    raise RedisClusterException("Redis Cluster cannot be connected. Please provide at least one reachable node.")
rediscluster.exceptions.RedisClusterException: Redis Cluster cannot be connected. Please provide at least one reachable node.

Any help would be great.

@Jacky i tried with both ports 6379 and 7000 for both section 1 and 2. — Umang Agrawal
– Umang Agrawal, Commented Jun 12, 2017 at 10:17
you need to contact to the redis administrator to make sure which port to use. And I want to know what exception raised if setting port to 6379 in section 2. Note that setting port to a number instead of string. — Jacky Wang
– Jacky Wang, Commented Jun 12, 2017 at 10:24

e7lT2P · Accepted Answer · 2017-06-13 07:27:08Z

Ok, so this error means one of the following:

In these lines of code (1):
```
r = redis.Redis(host='123.123.123.123', port=6379, db=0)

r.get('some srting')
```
you try to fetch the key "some sting" from host 123.123.123.123 and port 6379. The error redis.exceptions.ResponseError: MOVED 9442 172.16.176.36:6380 means that this key lies in 172.16.176.36:6380. So try to connect with ./redis-cli -c -p 6380 in this node and then execute CLUSTER GETKEYSINSLOT 6380 3 to see if this key is actually here.
From (2) this error: rediscluster.exceptions.RedisClusterException: Redis Cluster cannot be connected. Please provide at least one reachable node means that something is wrong with the cluster. Maybe, you have not made correct the initialization.

First in /home/{{user}}/redis-yourversion/utils/create-cluster you will find create-cluster.sh. Set up port and host and nodes and then execute ./create-cluster start ./create-cluster-create. But first you have to start redis server in cluster mode. Go to redis.conf and in the configuration parameters you will see cluster-enabled no. Set up to yes. After this you must run ./redis-server ../redis.conf (give the path for redis.conf). If cluster enabled is correct you will see Running in cluster mode

Important thing to remember:

The parameter -c in terminal means that redis nodes can execute the redirections and find the correct node that the key belongs without MOVED errors. If you have a driver suppose in python to manipulate the nodes and fetch keys or whatever you must manage these redirections by yourself.

Collectives™ on Stack Overflow

How to execute get command in redis cluster mode using python?

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related