CODEWITHSUNDEEP
pythonredissentinelredis-py
Neel
Neel

Reputation: 21315

How to create redis python client from sentinel url?

I have url as 

BROKER_URL = 'sentinel://192.168.10.1:26379/0;sentinel://192.168.10.2:26379/0;sentinel://192.168.10.3:26379/0'

In this, redis is running on 192.168.10.1, 192.168.10.2 and 192.168.10.3. One node is master and others are slaves. If master went down, other node take place for master.

I check the redis client but it has no method, where we can provide url like I gave.

We have to provide hostname and port. In my case, master will be anyone form these 3.

Upvotes: 5

Views: 22303

Answers (2)

SARA E
SARA E

Reputation: 189

To connect with python redis client, you can proceed as follows if you have an authentication required setup with password do as follows:

from redis.sentinel import Sentinel
sentinel = Sentinel([('192.168.10.1', 26379),
                     ('192.168.10.2',26379),
                     ('192.168.10.3',26379)],
                   sentinel_kwargs={'password': YOUR_REDIS_PASSWORD})
# you will need to handle yourself the connection to pass again the password
# and avoid AuthenticationError at redis queries
host, port = sentinel.discover_master(YOUR_REDIS_DB_MASTER)
redis_client = redis.StrictRedis(
            host=host,
            port=port,
            password= YOUR_REDIS_PASSWORD
        )

You can test it directly with a simple query like

redis_client.exists("mykey")

Of course if you didnt set up a password, you can remove the sentinel_kwargs={'password': YOUR_REDIS_PASSWORD} and the password attribute in your redis_client instance.

If the setup failed you might encounter a MasterNotFoundError (if sentinal discovery failed) or a AuthenticationError if you didn't pass the correct password or the password argument at the right place

Upvotes: 10

GuangshengZuo
GuangshengZuo

Reputation: 4687

Check the redis-py codebase readme.md at https://github.com/andymccurdy/redis-py/blob/master/README.rst#sentinel-support

Like this:

from redis.sentinel import Sentinel
sentinel = Sentinel([('192.168.10.1', 26379), ('192.168.10.2',26379), ('192.168.10.3',26379)], socket_timeout=0.1)

master = sentinel.master_for('master-name', socket_timeout=0.1)

The master and slave objects are normal StrictRedis instances with their connection pool bound to the Sentinel instance. When a Sentinel backed client attempts to establish a connection, it first queries the Sentinel servers to determine an appropriate host to connect to. If no server is found, a MasterNotFoundError or SlaveNotFoundError is raised.

The Actual thing is that if you build Sentinel for redis cluster, you do not need to connect the redis server directly. Do as above, first connect to Sentinel, and use master_for to query the an appropriate host to connect to. Only in this way, if master is down, your client could be directed to the new master.

And The master-name in the code above, you should specify in the sentinel.conf in

sentinel monitor <master-group-name> <ip> <port> <quorum>

like this:

sentinel monitor mymaster 127.0.0.1 6379 2

Upvotes: 12

Related Questions