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)
"25bfacb8-f9f0-4dcc-bda9-d49e1e29a644"
> (uuid-generate)
"2a91b83f-69f0-4355-9058-e4001be431f1"

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)
"5cec071b-b7d2-48ad-88fb-72a9f09c7505"
> (uuid-generate/random)
"0adf3c5a-9c6d-4ed8-9b60-a0a2bf5cf65d"

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)
"9eb9ab2c-65ae-11f1-8d5c-d77cb9662570"
> (uuid-generate/time)
"9eba3114-65ae-11f1-8d5c-d77cb9662570"