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)
"594564eb-2c00-42f7-91eb-d70be0ca161b"
> (uuid-generate)
"1461c0ff-5a36-463a-967f-ed0bf8c845ab"

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)
"ab4dd448-af21-4437-995a-e67cd1bf33a7"
> (uuid-generate/random)
"26caf9e6-7a9f-473c-ab13-235c8be8cae0"

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)
"71bd5f3a-5fc1-11f1-8ec2-0924798a42d6"
> (uuid-generate/time)
"71bd658e-5fc1-11f1-8ec2-0924798a42d6"