lua-snowflake

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

Installation

$ luarocks install snowflake

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 default

• 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 1609459200000 or 2021-01-01T00:00:00.000Z

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

• datacenter_id is an integer n, where 0 ≤ n < (1 << datacenter_id_bits) and specifies the ddddd portion of the id
• node_id is an integer n, where 0 ≤ n < (1 << node_id_bits) and specifies the nnnnn portion of the id
• snowflake_epoc is an integer n, the starting timestamp is expressed in milliseconds
• node_id_bits is an integer n, representing the node within a given data center
• datacenter_id_bits is an integer n, representing a unique data center or group of servers
• sequence_bits is an integer n, called multiple times for the same millisecond