Ways of using value provider parameter in Python Apache Beam

Question

Right now I’m just able to grab the RunTime value inside a class using a ParDo, is there another way to get to use the runtime parameter like in my functions?

This is the code I got right now:

class UserOptions(PipelineOptions):
    @classmethod
    def _add_argparse_args(cls, parser):
        parser.add_value_provider_argument('--firestore_document',default='')

def run(argv=None):

    parser = argparse.ArgumentParser()

    pipeline_options = PipelineOptions()

    user_options = pipeline_options.view_as(UserOptions)

    pipeline_options.view_as(SetupOptions).save_main_session = True

    with beam.Pipeline(options=pipeline_options) as p:

        rows = (p 
        | 'Create inputs' >> beam.Create(['']) 
        | 'Call Firestore' >> beam.ParDo(
                CallFirestore(user_options.firestore_document)) 
        | 'Read DB2' >> beam.Map(ReadDB2))

I want the user_options.firestore_document to be usable in other functions without having to do a ParDo

Asked By: Luis Antonio Gutierrez Flores

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Source

Answer 1

The only way in which you can use value providers are in ParDos, and Combines. It is not possible to pass a value provider in a create, but you can define a DoFn that returns the value provider you pass to it in the constructor:

class OutputValueProviderFn(beam.DoFn):
  def __init__(self, vp):
    self.vp = vp

  def process(self, unused_elm):
    yield self.vp.get()

And in your pipeline, you would do the following:

user_options = pipeline_options.view_as(UserOptions)

with beam.Pipeline(options=pipeline_options) as p:
  my_value_provided_pcoll = (
      p
      | beam.Create([None])
      | beam.ParDo(OutputValueProviderFn(user_options.firestore_document))

That way you wouldn’t use it in a Create, as it’s not possible, but you could still get it in a PCollection.

Answered By: Pablo

Ways of using value provider parameter in Python Apache Beam

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