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)
"aade0c24-95e8-43fd-882a-c7f8e7bc099b"
> (uuid-generate)
"2d88078d-d920-4fec-961d-a75aa801de14"

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)
"5d8c50ac-3f5a-4454-a500-7125f284f2b2"
> (uuid-generate/random)
"e4b6d62a-4615-40f4-bbe9-212829506d1b"

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)
"1dd61ca0-9aa3-11f1-872d-39ff60c1e717"
> (uuid-generate/time)
"1dd622ea-9aa3-11f1-872d-39ff60c1e717"