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)
"a6385eaa-e1ef-4c83-a67f-3b96af3a0e0f"
> (uuid-generate)
"36d05c29-14d9-4687-b5d3-65c48091ff70"

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)
"bd62dca0-0dae-4844-9a00-828da353a954"
> (uuid-generate/random)
"6d984517-84e3-4669-8186-fe7b673dc08a"

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)
"39c24bc8-eeaa-11f0-bcc2-af0a3646192b"
> (uuid-generate/time)
"39c303ce-eeaa-11f0-bcc2-af0a3646192b"