Skip to main content

Redis Sharding API

Project description

Redis Shard
###########

.. image:: https://img.shields.io/travis/zhihu/redis-shard.svg?style=flat
:target: https://travis-ci.org/zhihu/redis-shard
:alt: Build Status

.. image:: https://pypip.in/version/redis-shard/badge.svg?style=flat
:target: https://pypi.python.org/pypi/redis-shard
:alt: Latest Version

.. image:: https://pypip.in/py_versions/redis-shard/badge.svg?style=flat
:target: https://pypi.python.org/pypi/redis-shard
:alt: Supported Python versions

.. image:: https://pypip.in/license/redis-shard/badge.svg?style=flat
:target: https://pypi.python.org/pypi/redis-shard
:alt: License

A Redis sharding implementation.

Redis is great. It's fast, lightweight and easy to use. But when we want to store
a mass of data into one single instance, we may encounter some problems such as performance
degradation and slow recovery and we need to scale it.

Usage
=====

First, Create an RedisShardAPI instance with multiple nodes, node ``name`` **must be unique**::

from redis_shard.shard import RedisShardAPI

servers = [
{'name': 'server1', 'host': '127.0.0.1', 'port': 10000, 'db': 0},
{'name': 'server2', 'host': '127.0.0.1', 'port': 11000, 'db': 0},
{'name': 'server3', 'host': '127.0.0.1', 'port': 12000, 'db': 0},
]

client = RedisShardAPI(servers, hash_method='md5')

Then, you can access the Redis cluster as you use `redis-py <https://github.com/andymccurdy/redis-py>`_::

client.set('test', 1)
client.get('test') # 1
client.zadd('testset', 'first', 1)
client.zadd('testset', 'second', 2)
client.zrange('testset', 0, -1) # [first, second]


Hash Tags
---------

If you want to store specific keys on one node for some reason (such as you prefer single instance pipeline, or
you want to use multi-keys command such as ``sinter``), you should use Hash Tags::

client.set('foo', 2)
client.set('a{foo}', 5)
client.set('b{foo}', 5)
client.set('{foo}d', 5)
client.set('d{foo}e', 5)

client.get_server_name('foo') == client.get_server_name('a{foo}') == client.get_server_name('{foo}d') \
== client.get_server_name('d{foo}e') # True

The string in a braces of a key is the Hash Tag of the key. The hash of a Hash Tag will be treated the hash of the key.
So, keys ``foo``, ``bar{foo}`` and ``b{foo}ar`` will be sotred in the same node.


Config Details
--------------
There are three parameters ``servers``, ``hash_method`` and ``sentinel`` in the :class:`redis_shard.shard.RedisShardAPI`.

``servers`` is a list. Each element in it should be a dict or a URL schema.

- dict::

[
{'name': 'server1', 'host': '127.0.0.1', 'port': 10000, 'db': 0},
{'name': 'server2', 'host': '127.0.0.1', 'port': 11000, 'db': 0},
{'name': 'server3', 'host': '127.0.0.1', 'port': 12000, 'db': 0},
]

- URL schema::

[
'redis://127.0.0.1:10000/0?name=node1',
'redis://127.0.0.1:11000/0?name=node2',
'redis://127.0.0.1:12000/0?name=node3'
]

If the following parameter ``sentinel`` is enabled, only **name** is needed for the ``servers`` config.

``hash_method`` is a string which indicate the method of generating the hash key of the consistent hash ring.
The default value is **crc32**. It also supports **md5** and **sha1**.


``sentinel`` is the config for `Redis Sentinel <http://redis.io/topics/sentinel>`_. With the sentinel support, redis-shard
will do read/write splitting. Config is like this::

{"hosts": [('localhost', 26379)], "socket_timeout": 0.1}



Limitations
===========

* Redis Shard dose not support all Redis commands.
* As mentioned above, Redis Shard does not support multi-keys command crossing different nodes,
you have to use Hash Tag to work with those commands.
* Redis Shard does not have any replication mechanism.


How it Works
============

Redis Shard is basically inspired by `this article <http://oldblog.antirez.com/post/redis-presharding.html>`_.


Change History
==============

0.3.0 (2014-11-20)
------------------
- shard key generate function now support **md5** and **sha1** .
- add Redis Sentinel support

0.2.4 (2014-06-26)
------------------
- remove gevent dependency

0.2.3 (2014-06-02)
------------------
- better pipeline support

0.2.1 (2013-08-07)
------------------
- add evel method

0.2.0 (2013-06-02)
------------------
- add python3 support

0.1.11 (2013-05-06)
-------------------
- add mset support

0.1.10 (2013-04-13)
-------------------
- add mget support ,thks to @Yuekui

0.1.9 (2013-03-04)
------------------
- add an reshard example
- tidy the pipeline code
- add more shard methods

0.1.8 (2013-01-21)
------------------
- add `append` and `getrange` method, thks @simon-liu

0.1.7 (2012-11-19)
------------------
- use new redis url config instead of dict

0.1.5 (2012-07-16)
------------------
- Add many new methods, support socket_timeout and password

0.1.4 (2011-07-20)
------------------
- modify hash key algor, support suffix match, thks to dkong
- support more redis methods, include `keys`.

0.1.3 (2011-06-20)
------------------
- support 2.4.X version of redis-py

0.1.2 (2011-06-01)
------------------
- add MANIFEST.in file

0.1.1 (2011-05-29)
------------------
- create hashring use server's name config.

0.1 (2011-05-28)
----------------
- first version

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

redis-shard-0.3.0.tar.gz (11.7 kB view hashes)

Uploaded Source

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page