libuuid
uuid-generate
uuid-generate/  random
uuid-generate/  time
7.1

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)

"9b4576e9-cbf9-4f00-98aa-6388ceadcb92"

> (uuid-generate)

"1b68f1f0-119d-461a-9d57-547937306ecb"

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)

"8a4ecfe1-00d4-44a1-96c7-978b8818f432"

> (uuid-generate/random)

"a8a0c335-726f-4e36-99f5-0fe8ea9c9a7e"

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)

"c4487d26-da0d-11e8-a03f-17e25107733e"

> (uuid-generate/time)

"c4488b0e-da0d-11e8-a03f-17e25107733e"