如何优雅地中止pipelines管道？

Question

问题

我有一条管道链：

class PipelineA(base_handler.PipelineBase):
  def run(self, *args):
    # do something

class PipelineB(base_handler.PipelineBase):
  def run(self, *args):
    # do something


class EntryPipeline(base_handler.PipelineBase):
  def run(self):

    if some_condition():
      self.abort("Condition failed. Pipeline aborted!")

    yield PipelineA()

    mr_output = yield mapreduce_pipeline.MapreducePipeline(
      # mapreduce configs here
      # ...
    )

    yield PipelineB(mr_output)

p = EntryPipeline()
p.start()

在EntryPipeline中，在启动PipelineA、MapreducePipeline和PipelineB之前，我正在测试一些条件。如果条件失败，我希望中止EntryPipeline和所有后续管道。

问题

1. 什么是优雅的管道流产？self.abort()是正确的方法还是我需要sys.exit()
2. 如果我想在PipelineA内部做堕胎呢？例如，PipelineA成功启动，但防止后续管道(MapreducePipeline和PipelineB)启动。

编辑：

最后，我将条件语句移出EntryPipeline，因此，只有在条件为真的情况下才开始整个工作。否则我认为尼克的回答是正确的。

Answer 1

由于文档当前的名称是"TODO: Talk有关显式中止和重试“

我们将不得不阅读消息来源：

https://github.com/GoogleCloudPlatform/appengine-pipelines/blob/master/python/src/pipeline/pipeline.py#L703

  def abort(self, abort_message=''):
    """Mark the entire pipeline up to the root as aborted.
    Note this should only be called from *outside* the context of a running
    pipeline. Synchronous and generator pipelines should raise the 'Abort'
    exception to cause this behavior during execution.

    Args:
      abort_message: Optional message explaining why the abort happened.

    Returns:
      True if the abort signal was sent successfully; False if the pipeline
      could not be aborted for any reason.
    """

因此，如果您有一个some_pipeline的句柄不是self，您可以调用但是如果你想要中止你自己，你需要引发中止().它会泡到顶端，杀死整棵树