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)
"f722fba0-e527-4159-848f-d0005009f426"
> (uuid-generate)
"546b5ffe-7ea4-49b0-bbe1-7811309fa660"

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)
"8ffb9047-a32b-4165-90e5-dbff4fbeb503"
> (uuid-generate/random)
"1e02c583-e224-4cfc-adac-f1e6f41f44f0"

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)
"9cbf9574-cd60-11f1-8b35-751a77143859"
> (uuid-generate/time)
"9cbfcbfc-cd60-11f1-8b35-751a77143859"