Appengine pipeline, how to let function execute right after the pipeline work finish

Question

https://code.google.com/p/appengine-pipeline/wiki/GettingStarted#Execution_ordering

I tried to add a callback function which execute after the Log2Bq done. But it doesn't work either I use pipeline.After or pipeline.InOrder. In the following code sample, the taskqueue will execute immediate without waiting for Log2Bq. To fix the issue, do I need to create another pipeline to hold the taskqueue in order to make the execute order works?

class Log2Stat(base_handler.PipelineBase):
    def run(self, _date):
        print "start track"
        with pipeline.InOrder():
            yield pipelines.Log2Bq()

            print "finish track"
            taskqueue.add(
                url='/worker/update_daily_stat',
                params={
                    "date": str(_date.date())
                }
            )

Answer 1

pipeline.InOrder() and pipeline.After() are only for ordering pipelines execution, not code execution.

There is a method called finalized, that is executed right after the last output is written, that is when your Log2Bq() pipeline finish it's execution, so:

class Log2Stat(base_handler.PipelineBase):
    def run(self, _date):
        print "start track"
        yield pipelines.Log2Bq()

    def finalized(self):
        print "finish track"
        taskqueue.add(
            url='/worker/update_daily_stat',
            params={
                "date": str(_date.date())
            }
         )

If you want to use pipeline.InOrder() or pipeline.After() you should wrap your taskqueue code in other pipeline and yield it after pipelines.Log2Bq()

with pipeline.InOrder():
      yield pipelines.Log2Bq()
      yield pipelines.YourOtherPipeline()