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)
"3e782170-2b19-49de-8f9a-261e32ca7533"
> (uuid-generate)
"b020ce5a-da5d-4c73-942d-dbd35bd821d2"

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)
"71194aa7-1e4a-482c-b3db-14630e033cfc"
> (uuid-generate/random)
"716d3f25-bd4f-4d27-8eb7-19fc0b8b25f6"

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)
"db0f578a-ef3d-11f0-a9ad-69a41a33acb6"
> (uuid-generate/time)
"db0f8188-ef3d-11f0-a9ad-69a41a33acb6"