libuuid
uuid-generate
uuid-generate/  random
uuid-generate/  time
7.6

libuuid

Jan Dvorak <mordae@anilinux.org>

Interface to the libuuid library usable to generate high-quality UUIDs.

 (require libuuid) 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)

"1a2b8e57-2e4e-4fc1-bb86-81b18613af5f"

> (uuid-generate)

"181b1db6-1112-4e2e-aa83-60d98d8b42d6"

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)

"7e28b9b9-dc4a-4597-9d4e-4047c7897e69"

> (uuid-generate/random)

"0c71a768-fd5a-44e8-b978-f9fbc3a9443e"

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)

"17929960-4f6c-11ea-8b6f-595d67ce1d56"

> (uuid-generate/time)

"1792a522-4f6c-11ea-8b6f-595d67ce1d56"