example of wrapping an ActiveRecord class with a module that uses it so as to separate the behavior of AttachmentUploadStatus from the persistence concerns (and table name) of AttachmentUploadFailures since only failures are stored in the db.

attachment_upload_status.rb

# app/models/attachment_upload_status.rb
module AttachmentUploadStatus # no parent needed!
  def self.cache_key(attachment)
    "attachment_upload:#{attachment.global_id}:status"
  end
  
  def self.pending!(attachment)
    Rails.cache.write(cache_key(attachment), 'pending', expires_in: 1.day.from_now)
  end
  
  def self.success!(attachment)
    Rails.cache.delete(cache_key(attachment))
  end
  
  def self.failed!(attachment, error)
    attachment.shard.activate do
      AttachmentUploadFailure.create!(
        attachment: attachment,
        error: error
      ).tap { Rails.cache.delete(cache_key(attachment)) }
    end
  end
  
  # If Rails.cache has a status, use that. Otherwise check for AttachmentUploadFailure in db.
  # If everything is empty, means the upload was a success.
  def self.upload_status(attachment)
    status = Rails.cache.read(cache_key(attachment))
    return status if status
    return 'failed' if AttachmentUploadFailure.where(attachment: attachment).exists?
  
    'success'
  end

  class AttachmentUploadFailure < ApplicationRecord
    # I assume this table name would otherwise prepend `attachment_upload_status_` since that's this class's full object name
    self.table_name = :attachment_upload_failures 
    
    belongs_to :attachment

    validates :attachment, :error, presence: true
  end
end