Fiber使って、ActiveRecord::Base.transactionのblcok内でyieldして、beginとcommit/rollbackを別々の場所で実行するヤツ

resume_transaction.rb

fiber = Fiber.new {|commit|
  puts "fiber start"
  ActiveRecord::Base.transaction {
    puts "begin"
    Fiber.yield
    raise ActiveRecord::Rollback unless commit
    puts "commit"
  }
  puts "fiber end"
}

fiber.resume
puts "in tx"

dosomething_in_transaction()

fiber.resume(false) # rollback