buid: universally unique lexicographically sortable identifiers

This package provides an implementation of flake ids that are lexicographically-sortable and highly unlikely to collide in a distributed system.

BUIDs can (and are meant to!) be safely stored inside a PostgreSQL UUID field.

1 Spec

A BUID is made up of a 40 bit time component and an 88 bit randomness component. The time component represents the current number of centiseconds since the UNIX timestamp 1586026830000.

BUIDs are represented as 22 character strings where the first 7 characters represent the 0-padded time component encoded in base 62 and the remaining 15 characters represent the 0-padded randomness component encoded in base 62.

The randomness component must have its most significant bit initially set to 0 and all ids generated within the same centisecond must increase monotonically.

In binary, BUIDs are represented as 16 bytes, encoded in network order.

2 Reference

The generator functions are thread-safe.

> (require buid)

> (for ([_ (in-range 10)]) (displayln (buid)))

00GUkN3BfsY4SsGG6WtXC4 00GUkN3BfsY4SsGG6WtXC5 00GUkN3BfsY4SsGG6WtXC6 00GUkN3BfsY4SsGG6WtXC7 00GUkN3BfsY4SsGG6WtXC8 00GUkN3BfsY4SsGG6WtXC9 00GUkN3BfsY4SsGG6WtXCA 00GUkN3BfsY4SsGG6WtXCB 00GUkN3BfsY4SsGG6WtXCC 00GUkN3BfsY4SsGG6WtXCD