Flake UUID

Flake UUID is a Dart library that provides 64- and 128-bit, k-ordered identifiers, which preserve their order of creation (somewhat) if sorted lexically.

It generates conflict-free and unique identifiers without further coordination between the nodes on your cluster (assuming time goes forward and machine IDs are unique).

64-bit Flake ID

The 64-bit Flake ID is created with:

  • 42-bit timestamp (millis since epoch, good til the end of this century)
  • 10-bit machine ID
  • 11-bit sequence (incremented within the same millisecond)

A simple usage example, works only with Dart VM, because it uses the environment to generate a somewhat-random machine ID:

import 'package:flake_uuid/flake_uuid.dart';

main() {
  var x = flake64.nextInt();
  var y = flake64.nextHex(); // '2b06cca4f5542000'
}

A more detailed version if you use the class directly. You must supply a pre-coordinated machine ID:

import 'package:flake_uuid/flake_base.dart';

main() {
  var flake = new Flake64(machineId: 123);
  var x = flake.nextInt();
  var y = flake.nextHex();
}

128-bit Flake ID

The 128-bit Flake ID is created with:

  • 64-bit timestamps (macroseconds(!) since epoch, won't run out in your lifetime)
  • 48-bit machine ID
  • 16-bit sequence (incremented within the same macrosecond)

A simple usage example, works only with Dart VM, because it uses the environment to generate a somewhat-random machine ID:

import 'package:flake_uuid/flake_uuid.dart';

main() {
  var y = flake128.nextHex(); // '2b06cca4f5542000'
}

A more detailed version if you use the class directly. You must supply a pre-coordinated machine ID:

import 'package:flake_uuid/flake_base.dart';

main() {
  var flake = new Flake128(machineId: 123);
  var x = flake.nextInt(); // not recommended
  var y = flake.nextHex(); // '000540947b2305c4a25c0001c73a0000'
  var z = flake.nextUuid(); // '00054094-7b23-05c4-a25c-0001c73a0001'
}

Links

Libraries

flake_uuid

flake_uuid.base