libuuid
uuid-generate
uuid-generate/  random
uuid-generate/  time
7.0

libuuid

Jan Dvorak <[email protected]>

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)

"dc720b67-b447-4315-8e5e-342c3c888e7b"

> (uuid-generate)

"3c5b14e6-e27d-4fa3-be12-8bf53c14663d"

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)

"16717687-bf56-4f24-87ec-a45ea7c0fc39"

> (uuid-generate/random)

"0fbb9e13-c80b-4743-948c-1acae65c3509"

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)

"4a5a778c-9230-11e8-af90-a9d1cbe763af"

> (uuid-generate/time)

"4a5a8434-9230-11e8-af90-a9d1cbe763af"