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)
"405dde04-1453-491c-9f5f-a2bfc86e25de"
> (uuid-generate)
"a0b29f87-55a9-4f9f-87a5-b96c2fbeb7d4"

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)
"8c819cbd-86bb-4be3-bd8f-f5a8c74f70e1"
> (uuid-generate/random)
"a014e741-43fe-4357-a571-097f36fc3e29"

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)
"af859c9a-0f37-11f1-8e02-0da1f51e8a51"
> (uuid-generate/time)
"af85a32a-0f37-11f1-8e02-0da1f51e8a51"