redis-lua

About

redis-lua is a pure Lua client library for the Redis advanced key-value database.

Main features

• Support for Redis >= 1.2
• Command pipelining
• Redis transactions (MULTI/EXEC) with CAS
• User-definable commands
• UNIX domain sockets (when available in LuaSocket)

Examples of usage

Include redis-lua in your script

require 'redis'

Connect to a redis-server instance and send a PING command

local redis = Redis.connect('127.0.0.1', 6379)
local response = redis:ping()           -- true

It is also possible to connect to a local redis instance using UNIX domain sockets if LuaSocket has been compiled with them enabled (unfortunately it is not the default):

local redis = Redis.connect('unix:///tmp/redis.sock')

Set keys and get their values

redis:set('usr:nrk', 10)
redis:set('usr:nobody', 5)
local value = redis:get('usr:nrk')      -- 10

Sort list values by using various parameters supported by the server

for _,v in ipairs({ 10,3,2,6,1,4,23 }) do
    redis:rpush('usr:nrk:ids',v)
end

local sorted = redis:sort('usr:nrk:ids', {
     sort = 'asc', alpha = true, limit = { 1, 5 }
})      -- {1=10,2=2,3=23,4=3,5=4}

Pipeline commands

local replies = redis:pipeline(function(p)
    p:incrby('counter', 10)
    p:incrby('counter', 30)
    p:get('counter')
end)

Leverage Redis MULTI / EXEC transaction (Redis > 2.0)

local replies = redis:transaction(function(t)
    t:incrby('counter', 10)
    t:incrby('counter', 30)
    t:get('counter')
end)

Leverage WATCH / MULTI / EXEC for check-and-set (CAS) operations (Redis > 2.2)

local options = { watch = "key_to_watch", cas = true, retry = 2 }
local replies = redis:transaction(options, function(t)
    local val = t:get("key_to_watch")
    t:multi()
    t:set("akey", val)
    t:set("anotherkey", val)
end)

Get useful information from the server

for k,v in pairs(redis:info()) do 
    print(k .. ' => ' .. tostring(v))
end
--[[
redis_git_dirty => 0
redis_git_sha1 => aaed0894
process_id => 23115
vm_enabled => 0
hash_max_zipmap_entries => 64
expired_keys => 9
changes_since_last_save => 2
role => master
last_save_time => 1283621624
used_memory => 537204
bgsave_in_progress => 0
redis_version => 2.0.0
multiplexing_api => epoll
total_connections_received => 314
db0 => {keys=3,expires=0}
pubsub_patterns => 0
used_memory_human => 524.61K
pubsub_channels => 0
uptime_in_seconds => 1033
connected_slaves => 0
connected_clients => 1
bgrewriteaof_in_progress => 0
blocked_clients => 0
arch_bits => 32
total_commands_processed => 3982
hash_max_zipmap_value => 512
db15 => {keys=1,expires=0}
uptime_in_days => 0
]]

Dependencies

• Lua 5.1 or LuaJIT 2.0
• LuaSocket 2.0
• Telescope (required to run the test suite)

Links

Project

• Source code
• Issue tracker

Related

• Redis
• Git

Authors

Daniele Alessandri

Contributors

Leo Ponomarev

License

The code for redis-lua is distributed under the terms of the MIT/X11 license (see LICENSE).