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)
"4f531c5c-0485-4f93-a666-985a6419145a"
> (uuid-generate)
"c6131c03-4c7a-4115-84c0-f0619d53b617"

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)
"2ebe74f1-7d08-4ef1-b578-cbe578d25b5c"
> (uuid-generate/random)
"d8f090a9-598b-4117-8556-13e33db9a595"

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)
"0b884870-9526-11f1-ac27-9930760bb7d0"
> (uuid-generate/time)
"0b88ac5c-9526-11f1-ac27-9930760bb7d0"