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)
"f0b3675e-42fc-464a-96f9-c88fe0988d02"
> (uuid-generate)
"23e4ba54-4ad5-428d-927e-7c4839e57cfb"

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)
"c081a9e7-fec8-4fee-b82e-42312f670cc4"
> (uuid-generate/random)
"cadc3c42-b9f3-42d8-9619-451e62be7e6b"

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)
"73e7cc08-2ac6-11f1-8319-0bfb93a989d0"
> (uuid-generate/time)
"73e7d248-2ac6-11f1-8319-0bfb93a989d0"