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)
"8473b702-df1f-43d0-a465-bc041080cc71"
> (uuid-generate)
"cbe3a579-78e1-43cc-a50d-95c6ee7f4ae5"

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)
"8bc7695d-2b3f-4fd7-aa3d-53ebfece76e6"
> (uuid-generate/random)
"dca3715c-5f0c-4ed0-8f60-0dc8456ce48e"

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)
"2f822508-9651-11f1-b0ca-c7db92f4031b"
> (uuid-generate/time)
"2f82418c-9651-11f1-b0ca-c7db92f4031b"