Generate Timebased UUID in elixir

I just ported the Cassandra::Uuid::Generator code from the official Cassandra Ruby gem:
https://github.com/datastax/ruby-driver/blob/master/lib/cassandra/uuid/generator.rb#L157

defmodule TimeUuid do
  use Bitwise, only_operators: true

  @gregorian_offset 122192928000000000

  def new(date_time, jitter \\ nil) do
    jitter = jitter || :rand.uniform(65536)
    clock_id = :rand.uniform(65536)
    node_id = generate_node_id()
    usecs = DateTime.to_unix(date_time, :microsecond) + jitter

    t = @gregorian_offset + usecs * 10
    time_hi  = t &&& 0x0fff000000000000
    time_mid = t &&& 0x0000ffff00000000
    time_low = t &&& 0x00000000ffffffff
    version = 1
    clock_id = clock_id &&& 0x3fff
    node_id = node_id &&& 0xffffffffffff
    variant = 0x8000

    n = (time_low <<< 96) ||| (time_mid <<< 48) ||| (time_hi <<< 16)
    n = n ||| (version <<< 76)
    n = n ||| ((clock_id ||| variant) <<< 48)
    n = n ||| node_id

    <<n::integer-size(128)>>
    |> UUID.binary_to_string!()
  end

  def generate_node_id do
    :math.pow(2, 47)
    |> trunc()
    |> :rand.uniform()
    |> Bitwise.bor(0x010000000000)
  end

end

Can you explain how to do this? I just get…

** (ArgumentError) Invalid argument; Expected: <<clock_seq::14>>, <<node::48>>
    (uuid 1.1.8) lib/uuid.ex:250: UUID.uuid1/3

Thanks.

Snowflake IDs, GitHub - pggalaviz/exnowflake: A decentralized, unique, time based ID generator. · GitHub .

Docs:

By format I do not mean hexadecimal representation, but binary representation. Just to make it clear. String 46529a99-5727-4655-b1e9-58ebb8d90c6f is NOT UUID.

Exactly. That was the most annoying part for me: having to convert from one format to another. I didn’t really need ULID anyway, but it was nice to get some experience with it.

My problem with ULID is that it is only length-compatible with UUID, not format-compatible, so it cannot be added to the UUID specs as a new version to the IETF RFC. That is why I prefer UUIDv6 proposal, which could be handled in PostgreSQL and any other implementation with almost no changes to the code.

I’ll throw ecto_ulid out there too. ULID is a pretty nice ID type (and while I realize this post is about IDs in Cassandra) but its lack of support in Postgres turned into a PITA. I was storing it as a :binary_id since it’s a 128bit integer but querying by the human-readable format was impossible; I had to convert it manually and that got old.

Anyway, here’s a good write-up of the differences between ULID & KSUID. Both are likely great options for your use case.

For lexicographically sortable UUIDs I prefer UUIDv6.

KSUID is great, and monotonically increasing. Couldn’t push for it more.

ksuid is sortable uuid