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Znowflake

Znowflake is a network service for generating unique 64-bit ID numbers. It's similar to Twitter's Snowflake. Znowflake is implemented in C with ZeroMQ via CZMQ.

Details

Please read the documents for Snowflake. Our motivation and requirements are similar.

There are some differences:

  • Wider machine ID field
  • Epoch at 1337000000 (May 14, 2012)
  • Quits generating unique IDs sooner (good for around 17 years)
  • Relaxed performance and resolution requirements

Usage

Server

Znowflake is a Linux daemon. It might compile on other systems - give it a shot.

It accepts options for port number, machine number, and an option to daemonize. If the port isn't given, it defaults to 23138.

znowflaked -p 5555 -m 7384

This gets a ZMQ_REP socket listening on port 5555.

Configuration File

znowflaked also reads a simple libconfig-based configuration file:

znowflaked -f /etc/znowflaked/znowflaked.conf

Sample configuration file contents:

machine: 2849;
port: 4242;

To daemonize, pass in the -d flag:

znowflaked -d -m 100

Startup Script

An init script for CentOS is found in the znowflaked.sh file. Get the whole thing running:

gcc znowflaked.c -lconfig -lczmq -lzmq -o /usr/local/bin/znowflaked
cp znowflaked.sh /etc/init.d/znowflaked
vi /etc/znowflake/znowflake.conf
service znowflaked start

Start on boot:

chkconfig --add znowflaked
chkconfig znowflaked on

Example Clients

client.c and client.rb show you how to get IDs from the server.

cclient.c is a continuously running client, useful for testing.

cclient -p 1234 -r 1000

grabs IDs from port 1234 at a rate of 1000 per second. Try running multiple instances of cclient.