ApplicationService running a retryable REPEATABLE READ transaction

application_service.rb

def call(form, attempts_count = 0, &block)
  return block.call(form).unwrap unless transaction_handler.enabled?
  return transaction_handler.transaction { block.call(form).unwrap } if nested_transaction_detector.call

  if attempts_count < max_attempts
    begin
      attempts_count = attempts_count + 1

      transaction_handler.transaction(isolation: :repeatable_read) { block.call(form, attempt: attempts_count).unwrap }
    rescue Survivor::Adapters::Error => error
      if error.respond_to?(:cause) && error.cause.is_a?(ActiveRecord::StatementInvalid) && error.cause.cause.message.include?("could not serialize access due to concurrent update")
        form.errors.clear

        call(form, attempts_count, &block)
      else
        raise error
      end
    end
  else
    raise UncommittableRepeatableReadTransactionError.new(max_attempts)
  end
end

example_service.rb

def call(form)
  repeatable_transaction(form) do |form, attempt: 1, outcome: Outcome.new|
    capture { validate form }
      .then { create_transfer form, outcome }
      .then { activate_entry form, outcome }
      .then { outcome.transfer }
  end
end