assistant-storefront/app/models/jsonb_attributes_length_validator.rb

class JsonbAttributesLengthValidator < ActiveModel::EachValidator
  def validate_each(record, attribute, value)
    return if value.empty?

    @attribute = attribute
    @record = record

    value.each do |key, attribute_value|
      validate_keys(key, attribute_value)
    end
  end

  def validate_keys(key, attribute_value)
    case attribute_value.class.name
    when 'String'
      @record.errors.add @attribute, "#{key} length should be < 1500" if attribute_value.length > 1500
    when 'Integer'
      @record.errors.add @attribute, "#{key} value should be < 9999999999" if attribute_value > 9_999_999_999
    end
  end
end