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)
"69a8bf60-7d72-43fc-91d2-0f4100aae6ad"
> (uuid-generate)
"ae8a0ee5-117a-4cdd-b1fb-d7f6be70d0c5"

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)
"74f76c47-d5d0-46f3-bca6-6adcacd32328"
> (uuid-generate/random)
"98f821d0-2579-4fe0-b7dc-44a79779fdb7"

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)
"5948fb48-5eb5-11f0-aa9d-919496ae9151"
> (uuid-generate/time)
"59491fba-5eb5-11f0-aa9d-919496ae9151"