Persisting Configuration in Lua Scripts¶

Lua comes with several options for reading and writing configuration files in a variety of formats.

Configuration File Formats¶

Lua Tables¶

The most straightforward approach to persisting configuration in Lua is to use Lua itself. Tables in Lua can be persisted to files and loaded back in by Lua scripts. Tables look very similar to JSON in structure.

Example Lua table as a configuration file:

return {
  setting1 = true,
  setting2 = 5,
  ['multiple word setting'] = 'some value',
  nestedSettings = {
    settingA = 1,
    settingB = false
  }
}

mq.pickle¶

This is a built-in function provided by MQ for serializing a Lua table to a file.

local mq = require('mq')

-- initialize your config table
local myconfig = {}
-- name of config file in config folder
local path = 'pickletestcfg.lua'
-- attempt to read the config file
local configData, err = loadfile(mq.configDir..'/'..path)
if err then
    -- failed to read the config file, create it using pickle
    mq.pickle(path, myconfig)
elseif configData then
    -- file loaded, put content into your config table
    myconfig = configData()
end
-- print the contents
for k,v in pairs(myconfig) do print(k,v) end

myconfig.testkey = 'testvalue'

-- save the config
mq.pickle(path, myconfig)

Many table serialization options on lua-users¶

The lua-users wiki provides many example Lua table serialization implementations.

YAML¶

YAML provides an easy to read format if you don't mind being dependent on proper indentation.

settings:
- setting1: somevalue
- setting2:
  - nestedSetting: anothervalue

lyaml LuaRock¶

The MQ LuaRocks server has a version of lyaml available which can be installed using the Lua PackageMan script provided by MQ.

local lyaml = PackageMan.Require('lyaml')

More info on lyaml here.

JSON¶

{
  "setting1": "somevalue",
  "setting2": {
    "nestedSetting": "anothervalue"
  }
}

cjson LuaRock¶

The MQ LuaRocks server has a version of cjson available which can be installed using the Lua PackageMan script provided by MQ.

local cjson = PackageMan.Require('lua-cjson', 'cjson')

More info on cjson here

SQLite3¶

If you would prefer to use a database over a text based configuration file, SQLite3 is supported as well.

libsqlite3¶

The MQ LuaRocks server has a version of lsqlite3 available which can be installed using the Lua PackageMan script provided by MQ.

local sql = PackageMan.Require('lsqlite3')

More info on lsqlite3 here

INI¶

mq.TLO.Ini and /ini command¶

MQ has the Ini TLO and /ini commands which are used heavily by macros and work well for reading and writing INI files. Refer to the reference pages for more info on them.

LIP.lua Lua INI Parser¶

Lua INI Parser is a tiny Lua library allowing to handle .ini files. https://github.com/Dynodzzo/Lua_INI_Parser