function append_timestamp(tag, timestamp, record)
    new_record = record
    new_record["timestamp"] = timestamp
    return 1, timestamp, new_record
end

function format_timestamp(tag, timestamp, record)
        new_record = record
        print(new_record["timestamp"])
        new_record["timestamp"] = new_record["timestamp"]:gsub(",", ".")
        return 1, timestamp, new_record
end

function stringtonumber(tag, timestamp, record)
        new_record = record
        new_record["response_time"] = tonumber(new_record["response_time"])
        return 1, timestamp, new_record
end

function stringtonumber(tag, timestamp, record)
        new_record = record   
        new_record["time"] = new_record["time"]:gsub("Jan", "01"):gsub("Feb", "02"):gsub("Mar", "03"):gsub("Apr", "04"):gsub("May", "05"):gsub("Jun", "06"):gsub("Jul", "07"):gsub("Aug", "08"):gsub("Sep", "09"):gsub("Oct", "10"):gsub("Nov", "11"):gsub("Dev", "12")
        temp = {}
        for word in new_record["time"]:gmatch("%S+") do
                table.insert(temp, word)
        end
        new_record["time"] = string.format("%s-%s-%s %s.000", temp[4], temp[3], temp[2], temp[5])
end

os.time() - get current epoch value
os.time{ ... } - get epoch value for local date/time values
os.date("*t"),os.date("%format") - get your local date/time
os.date("!*t") or os.date("!%format") - get GMT date/time
os.date("*t", timestamp),os.date("%format", timestamp) - get your local date/time for given timestamp
os.date("!*t", timestamp) or os.date("!%format", timestamp) - get GMT date/time for given timestamp