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NATS Unique Identifiers

https://github.com/nats-io/nuid

A Lua module for generating highly performant, unique identifiers (NUIDs) using LuaJIT's FFI (Foreign Function Interface) for enhanced numerical precision and efficiency.

Features

  • Generates unique identifiers combining random and sequential components.
  • Leverages LuaJIT's FFI for 64-bit arithmetic, ensuring precise handling of large numbers.
  • Customizable length for the random prefix and sequential part.
  • Efficient string handling and generation.

Requirements

  • LuaJIT

Installation

Simply include the nuid.lua file in your Lua project and require it in your script.

Usage

local nuid = require("nuid")

-- Create a new NUID generator with default settings
local generator = nuid()

-- Generate the next new unique identifier result
local id = generator:next()
print(id)

-- Calling the generator will also produce the next result
print(generator())
  -- nataW3t1nKzs3iOIofD1Om
-- working example
local mailbox_nuid = nuid()
local mailbox_nuid_tail = nuid({preLen=8,seqLen=0})
function nats.create_inbox() return concat({'_INBOX.', mailbox_nuid(),".",mailbox_nuid_tail()}) end

-- _INBOX.AKVlRx7reWcacdtRxHYjnc.nNWzXCMR
-- _INBOX.AKVlRx7reWcacdtRxHYjhu.WxP4Bh8S
-- _INBOX.AKVlRx7reWcacdtRxHYjcC.9bOjBFdf

Customization

You can customize the length of the prefix and sequential part as well as the minimum and maximum increment values.

local generator = nuid({
    preLen = 12,  -- Length of the random prefix
    seqLen = 10,  -- Length of the sequential part
    minInc = 33,  -- Minimum increment for the sequential part
    maxInc = 333  -- Maximum increment for the sequential part
})

API Reference

  • nuid(opts): Creates a new NUID generator. opts is an optional table for customization.
  • generator:next(): Generates and returns a new unique identifier.

How It Works

The module utilizes LuaJIT's FFI to interface with C standard library functions for random number generation and floor operation. It combines a random prefix (generated using a 64-bit random number) with a sequential number that increments with each call to :next(). This approach ensures a high degree of uniqueness for each generated identifier.

License

This module is available under the MIT License.