Racket

libuuid🔗ℹ

Interface to the libuuid library usable to generate high-quality UUIDs.

package: libuuid

procedure
(uuid-generate) → string?

Generate new universally unique identifier using /dev/urandom, if available. If it is not available, use current time, local ethernet MAC address and random data from a pseudo-random generator.

Examples:

> (uuid-generate)
"b35d4c02-5047-4eeb-a138-6f17c7f7386c"
> (uuid-generate)
"344651d2-89be-4234-b384-756c2d320087"

procedure
(uuid-generate/random) → string?

When /dev/urandom is available, same as uuid-generate, but fails back to a pseudo-random generator only.

Can be used to prevent any chance of host’s MAC address leaking, at the cost of slightly higher chance of generating non-unique identifiers if the worst-case situation arises on multiple hosts.

Examples:

> (uuid-generate/random)
"8f9e16d1-41c6-4aa6-821a-949729fb7a2f"
> (uuid-generate/random)
"058d1a3e-8987-467b-a3b5-d88d0f41fb61"

procedure
(uuid-generate/time) → string?

Same as uuid-generate when the /dev/urandom is missing.

Could potentially produce non-uniqueue identifiers if used concurrently so if you do not absolutely need sequential identifiers, stick with the generic (and safe) uuid-generate function above.

Examples:

> (uuid-generate/time)
"94deb35e-39e4-11f1-a61b-872071e2d941"
> (uuid-generate/time)
"94dedaf0-39e4-11f1-a61b-872071e2d941"