UidAttribute

Auto-assign UUIDs to PORO and ActiveRecord attributes. Defaults to UUID v7 (RFC 9562 §5.7) — time-ordered, monotonic, B-tree friendly — with v4 (RFC 9562 §5.4) available when entropy beats time-ordering.

This gem is to UUIDs what ip_attribute is to IP addresses: a thin, convention-driven layer that auto-detects an attribute and keeps it populated.

gem "uid_attribute"

Convention: any column named uid or uuid is auto-detected.

class Order < ActiveRecord::Base
  include UidAttribute::ActiveRecordIntegration
end

Order.create!.uid  # => "018f4d9c-7a8b-7000-9b2a-1c3d4e5f6a7b" (v7)

Override the column or version explicitly:

class Order < ActiveRecord::Base
  include UidAttribute::ActiveRecordIntegration
  uid_attribute :public_id, version: 4
end

The mixin installs a before_validation(on: :create) callback that populates the attribute when blank. Presence and uniqueness validators are added by default — disable with validate: false.

class Job
  include UidAttribute::Poro
  attr_accessor :uid
end

Job.new.uid  # => "018f4d9c-..."

Custom attribute and version:

class Job
  include UidAttribute::Poro
  attr_accessor :public_id
  uid_attribute :public_id, version: 4
end

No mixin required:

UidAttribute::Generator.generate              # => v7 (default)
UidAttribute::Generator.generate(version: 4)  # => v4
UidAttribute::Generator.valid?(str)           # => true / false
UidAttribute::Generator.version_of(str)       # => 1..7 or nil

For non-AR models or explicit AR columns:

class Request
  include ActiveModel::Model
  include ActiveModel::Attributes

  attribute :token, UidAttribute::Type.new
end

With Rails, :uuid_string is auto-registered via Railtie:

attribute :public_id, :uuid_string

require "uid_attribute/core_ext"
using UidAttribute::CoreExt

"018f4d9c-7a8b-7000-9b2a-1c3d4e5f6a7b".uuid?         # => true
"018f4d9c-7a8b-7000-9b2a-1c3d4e5f6a7b".uuid_version  # => 7

Lexically scoped — no global monkey-patching.

UUID v7 embeds a millisecond Unix timestamp in the leading 48 bits. Sequential inserts cluster physically in B-tree indexes, avoiding the index fragmentation that v4 causes at scale.

• Ruby >= 3.4.0 (for SecureRandom.uuid_v7, shipped in 3.3+)
• ActiveModel / ActiveSupport >= 7.2 (runtime)
• ActiveRecord >= 7.2 (only for ActiveRecordIntegration)

Tested against Ruby 3.4 + 4.0 × ActiveRecord 7.2 + 8.1.

MIT — see LICENSE.