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)
"859a01f9-3725-4fde-aeaa-1becf0d606d4"
> (uuid-generate)
"56c99057-5e5a-48d1-b841-cfa8646e5c41"

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)
"f98056eb-6148-4441-8ed4-6ec9839b1fb9"
> (uuid-generate/random)
"636be915-17fe-4535-9529-a34ff3328eee"

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)
"fcff6642-5972-11f1-aa98-4b7363f57f75"
> (uuid-generate/time)
"fcff73bc-5972-11f1-aa98-4b7363f57f75"