example.py

import apache_beam as beam
from apache_beam.options.pipeline_options import PipelineOptions

class ConvertToByteArray(beam.DoFn):
    def __init__(self):
        pass

    def setup(self):
        pass

    def process(self, row):
        try:
            yield bytearray(row + '\n', 'utf-8')

        except Exception as e:
            raise e

def run():
    options = PipelineOptions([
  
        "--runner=PortableRunner",
        "--job_endpoint=10.0.2.15:30090",
        "--artifact_endpoint=10.0.2.15:30091",
        "--save_main_session",
        "--environment_type=DOCKER",
        "--environment_config=docker.io/apache/beam_python3.7_sdk:2.33.0"

    ])

    with beam.Pipeline(options=options) as p:
        lines = (p
        | 'Create words' >> beam.Create(['this is working'])
        | 'Split words' >> beam.FlatMap(lambda words: words.split(' '))
        | 'Build byte array' >> beam.ParDo(ConvertToByteArray())
        | 'Group' >> beam.GroupBy() # Do future batching here
        | 'print output' >> beam.Map(print)
        )

if __name__ == "__main__":
    run()