ruby-on-rails - 如何判断 ActiveRecord::Base.transaction block 何时提交？

Question

common problem使用后台作业和 ActiveRecord 是在将所需模型提交到数据库之前将作业排入队列并执行。

ActiveRecord 模型有一个不错的 after_commit可用于特定模型的回调。

但是，假设您有一些涉及几个不同模型的业务逻辑，将这些逻辑塞进单个模型中是不合适的。因此，您编写某种服务/命令对象来执行事务块内的逻辑:

例如，类似于以下内容:

class SomeServiceObject

  def execute
    thing = create_thing_in_a_tx

    # this notification often fires before the above transaction commits.
    notify_user(thing)
  end

  private

  def create_thing_in_a_tx
    ActiveRecord::Base.transaction do
      a = ModelA.new(foo: 'bar')
      b = ModelB.new(a_record: a, biz: 'baz')
      #... various other logic that doesn't really belong in a model ...
      ThingModel.create!(b_record: b)
    end
  end

  def notify_user(thing)
    EnqueueJob.process_asyc(thing.id)
  end
end

在这种情况下，据我所知，您实际上无法访问方便的 after_commit打回来。

我想在上面的例子中，你可以有 ThingModel将作业排入其 after_commit回调，但随后您正在传播 SomeServiceObject 应该承担的责任跨不同的类(class)，这感觉不对。

鉴于以上所有情况，是否有任何合理的方法可以知道何时 ActiveRecord::Base.transaction阻止提交，而无需求助于任何特定模型的 after_commit打回来？

谢谢! :-D

(另见: How to force Rails ActiveRecord to commit a transaction flush)

Answer 1

它比你想象的要简单。后 ActiveRecord::Base.transaction块完成，事务已提交。

def create_thing_in_a_tx
  begin
    ActiveRecord::Base.transaction do
      a = ModelA.new(foo: 'bar')
      b = ModelB.new(a_record: a, biz: 'baz')
      #... various other logic that doesn't really belong in a model ...
      ThingModel.create!(b_record: b)
    end
    # The transaction COMMIT has happened.  Do your after commit logic here.
  rescue # any exception
    # The transaction was aborted with a ROLLBACK.  
    # Your after commit logic above won't be executed.
  end
end