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import apache_beam as beam
from generate_event import GenerateEvent
from apache_beam.transforms.window import FixedWindows
from apache_beam.transforms.trigger import AccumulationMode
from apache_beam.transforms.trigger import AfterWatermark
from apache_beam.utils.timestamp import Duration
from apache_beam.options.pipeline_options import PipelineOptions
from apache_beam.options.pipeline_options import StandardOptions
from log_elements import LogElements


def apply_transform(events):
    return (events
            | beam.WindowInto(FixedWindows(5),
                              trigger=AfterWatermark(),
                              accumulation_mode=AccumulationMode.DISCARDING,
                              allowed_lateness=Duration(seconds=0))
            | beam.CombineGlobally(beam.combiners.CountCombineFn()).without_defaults())


def main():
    options = PipelineOptions()
    options.view_as(StandardOptions).streaming = True
    with beam.Pipeline(options=options) as p:
        events = p | GenerateEvent.sample_data()
        output = apply_transform(events)
        output | LogElements(with_window=True)


if __name__ == "__main__":
    main()
