A logging object for Lua

README.md

An example of usage is the following

local Logger = require("objects/logger")

logger = Logger:new(Logger.ERROR())

logger:debug("%s %d", "this is a debug", 1)

logger:error("%s %d", "this is an error", 2)

logger:setLogLevel(Logger.DEBUG())

logger:debug("%s %d", "Notice how you couldn't see the other debug?", 1)

logger.lua

local Object = require "objects/object"
local LogLevel = require "loglevel"

local DEBUG = LogLevel:new(1, "DEBUG")
local INFO  = LogLevel:new(2, "INFO")
local WARN  = LogLevel:new(3, "WARN")
local ERROR = LogLevel:new(4, "ERROR")

local Logger = Object:new{
    log_level = nil
}

function Logger.DEBUG()
    return DEBUG
end

function Logger.INFO()
    return INFO
end

function Logger.WARN()
    return WARN
end

function Logger.ERROR()
    return ERROR
end

local function __init(obj, logLevel)
    if not LogLevel.isInstanceOf(logLevel) then
        logLevel = INFO
    end
    obj.log_level = logLevel
    return true
end

function Logger:new(...)
    local obj = {}
    setmetatable(obj, self)
    self.__index = self
    self.__type = "Logger"
    __init(obj, ...)
    return obj
end

function Logger:setLogLevel(logLevel)
    self.log_level = logLevel
end

local function __log(self, logLevel, format, ...)
    if not LogLevel.isInstanceOf(logLevel) then
        return
    end
    if format == nil then
        return
    end

    if logLevel.value < self.log_level.value then
        return
    end

    local logStr = string.format("[%-5s] " .. format, logLevel:toString(), ...)
    print(logStr)
end

function Logger:debug(format, ...)
    __log(self, DEBUG, format, ...)
end

function Logger:info(format, ...)
    __log(self, INFO, format, ...)
end

function Logger:warn(format, ...)
    __log(self, WARN, format, ...)
end

function Logger:error(format, ...)
    __log(self, ERROR, format, ...)
end

return Logger

loglevel.lua

local Object = require "objects/object"

local LogLevel = {
    value = nil,
    string  = nil
}

local function __init(obj, value, str)
    obj.value = value
    obj.string = str or ""
    return true
end

function LogLevel:new(...)
    local obj = {}
    setmetatable(obj, self)
    self.__index = self
    self.__type = "LogLevel"
    __init(obj, ...)
    return obj
end

function LogLevel:toString()
    return self.string
end

function LogLevel.isInstanceOf(obj)
    return obj ~= nil and obj.__type == "LogLevel"
end

return LogLevel

object.lua

local Object = {
    __type = nil
}

function Object:new()
    local obj = {}
    setmetatable(obj, self)
    self.__index = self
    self.__type = type(self)
    return obj
end

function Object:equals(other)
    return self == other
end

function Object:toString()
    return tostring(self)
end

function Object:isInstanceOf(self, other)
    if other == nil then
        return false
    end
    return self.__type == other.__type
end

function Object.isInstanceOf(obj, type)
    if obj == nil then
        return false
    end
    return obj.__type == type
end

return Object