Lua logger module (inspired by log4j)

log.lua

--[[
    Lua log module
    @author Eliran Bivas
    
    Usage:

    local log = require "log"

    log.debug("some debug")
    log.info("some info")
    log.warn("some warn")
    log.error("some error")
       
]]

local enum = require "enum"
local utils = require "utils"

local levels = {'DEBUG', 'INFO', 'WARN', 'ERROR'}
local keys = utils.invertTable(levels) -- based on http://stackoverflow.com/q/9754285/422651

local log = {
    level = enum(levels), -- based on http://lua-users.org/lists/lua-l/2007-06/msg00433.html
    rootLevel = 'DEBUG',
}

local function enabled(level)
  if keys[log.rootLevel] <= keys[level] then return true end 
  return false
end

local function internalPrint(level, s)
  if enabled(level) then
    print(s)
  end
end

log.debug = function(s)
  internalPrint('DEBUG', '[DEBUG] ' .. s)
end

log.info = function(s) 
  internalPrint('INFO', '[INFO]  ' .. s)
end

log.warn = function(s) 
  internalPrint('WARN', '[WARN]  ' .. s)
end

log.error = function(s) 
  internalPrint('ERROR', '[ERROR] ' .. s)
end

return log