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lua-snowflake

An implementation of Snowflake for Lua. Snowflake is an algorithm which supports ordered, distributed id generation.

Installation

$ luarocks-5.4 make rockspec/snowflake-1.0-1.rockspec

Usage

local sf = require "snowflake"
sf.init(0x01, 0x01)
local uuid = sf.next_id()

uuid will be a 64-bit number represented as a string that is structured as follows:

6  6         5         4         3         2         1         
3210987654321098765432109876543210987654321098765432109876543210

tttttttttttttttttttttttttttttttttttttttttdddddnnnnnsssssssssssss

where

  • s is a 12-bit integer that increments when next_id() is called multiple times for the same millisecond
  • n is a 5-bit integer representing the node within a given data center
  • d is a 5-bit integer representing a unique data center or group of servers
  • t is a 42-bit integer representing the current timestamp in milliseconds
    • the number of milliseconds to have elapsed since 1413817200000 or 2014-10-20T15:00:00.000Z

sf.init(datacenter_id, node_id) is used to initialize snowflake and set values for ddddd and nnnnn as follows:

  • datacenter_id is an integer n, where 0 ≤ n ≤ 0x1f and specifies the ddddd portion of the id
  • node_id is an integer n, where 0 ≤ n ≤ 0x1f and specifies the nnnnn portion of the id