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)
"6529453b-e5a1-46b3-8d1b-07d92598b635"
> (uuid-generate)
"f7703e2d-6aa2-4900-95c1-c9113adc0184"

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)
"2ce2e440-cdbe-4a7b-bcf5-154ecf24466d"
> (uuid-generate/random)
"353153bd-db40-4b72-bf4c-636ca74e27bb"

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)
"b82d31ca-c178-11f1-8432-f7b70854c1e5"
> (uuid-generate/time)
"b82d5ccc-c178-11f1-8432-f7b70854c1e5"