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riak: Lua riak protocol buffer client driver for nginx-module-lua based on the cosocket API


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CentOS/RHEL 7 or Amazon Linux 2

yum -y install
yum -y install lua-resty-riak

CentOS/RHEL 8+, Fedora Linux, Amazon Linux 2023

yum -y install
yum -y install lua5.1-resty-riak

To use this Lua library with NGINX, ensure that nginx-module-lua is installed.

This document describes lua-resty-riak v2.0.0 released on Dec 05 2013.

lua-resty-riak - Lua riak protocol buffer client driver for the ngx_lua based on the cosocket API.

Originally based on the lua-resty-memcached library.

Influence by riak-client-ruby


This library is currently alpha quality. It passes all its unit tests. A few billion requests per day are handled by it however.


This Lua library is a riak protocol buffer client driver for the ngx_lua nginx module

This Lua library takes advantage of ngx_lua's cosocket API, which ensures 100% nonblocking behavior.

Note that at least ngx_lua 0.5.0rc29 or ngx_openresty is required.

Depends on the following Lua modules:


location /t {
    content_by_lua '
        require "luarocks.loader"
        local riak = require "resty.riak"
        local client =
        local ok, err = client:connect("", 8087)
        if not ok then
            ngx.log(ngx.ERR, "connect failed: " .. err)
        local bucket = client:bucket("test")
        local object = bucket:new("1")
        object.value = "test"
        object.content_type = "text/plain"
        local rc, err = object:store()
        local object, err = bucket:get("1")
        if not object then


See the generated docs for usage and examples.

Note The high level API should be considered stable - ie will not break between minor versions. The low-level or raw API should not be considered stable.

Potentially Breaking Change in 2.0

2.0.0 now uses vector clocks for gets,sets, and deletes of objects. If you are using a bucket that allows multiple values (siblings) then this may break your application.


  • This library cannot be used in code contexts like set_by_lua, log_by_lua, and header_filter_by_lua where the ngx_lua cosocket API is not available.
  • The resty.riak object instances cannot be stored in a Lua variable at the Lua module level, because it will then be shared by all the concurrent requests handled by the same nginx worker process (see Data Sharing within an Nginx Worker ) and result in bad race conditions when concurrent requests are trying to use the same instances. You should always initiate these objects in function local variables or in the ngx.ctx table. These places all have their own data copies for each request.



You may find additional configuration tips and documentation for this module in the GitHub repository for nginx-module-riak.