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)
"4d07295d-950f-4755-9834-bd11703b0b5d"
> (uuid-generate)
"b3de6732-f451-4df1-b008-3fa8b511e828"

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)
"7fbb43ae-ad00-48c6-a3ca-dc4302f1a38d"
> (uuid-generate/random)
"bc57fd08-6f07-4b06-9a98-e2584d90aef3"

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)
"6654ea7c-6aa3-11f1-a558-2d9e91778e9f"
> (uuid-generate/time)
"66553bee-6aa3-11f1-a558-2d9e91778e9f"