| # |
| # Licensed to the Apache Software Foundation (ASF) under one or more |
| # contributor license agreements. See the NOTICE file distributed with |
| # this work for additional information regarding copyright ownership. |
| # The ASF licenses this file to You under the Apache License, Version 2.0 |
| # (the "License"); you may not use this file except in compliance with |
| # the License. You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| # |
| |
| """Various implementations of a Count custom PTransform. |
| |
| These example show the different ways you can write custom PTransforms. |
| """ |
| |
| from __future__ import absolute_import |
| |
| import argparse |
| import logging |
| |
| import apache_beam as beam |
| from apache_beam.io import ReadFromText |
| from apache_beam.io import WriteToText |
| from apache_beam.options.pipeline_options import PipelineOptions |
| |
| # pylint doesn't understand our pipeline syntax: |
| # pylint:disable=expression-not-assigned |
| |
| |
| class Count1(beam.PTransform): |
| """Count as a subclass of PTransform, with an apply method.""" |
| |
| def expand(self, pcoll): |
| return ( |
| pcoll |
| | 'ParWithOne' >> beam.Map(lambda v: (v, 1)) |
| | beam.CombinePerKey(sum)) |
| |
| |
| def run_count1(known_args, options): |
| """Runs the first example pipeline.""" |
| logging.info('Running first pipeline') |
| with beam.Pipeline(options=options) as p: |
| (p | beam.io.ReadFromText(known_args.input) |
| | Count1() |
| | beam.io.WriteToText(known_args.output)) |
| |
| |
| @beam.ptransform_fn |
| def Count2(pcoll): # pylint: disable=invalid-name |
| """Count as a decorated function.""" |
| return ( |
| pcoll |
| | 'PairWithOne' >> beam.Map(lambda v: (v, 1)) |
| | beam.CombinePerKey(sum)) |
| |
| |
| def run_count2(known_args, options): |
| """Runs the second example pipeline.""" |
| logging.info('Running second pipeline') |
| with beam.Pipeline(options=options) as p: |
| (p | ReadFromText(known_args.input) |
| | Count2() # pylint: disable=no-value-for-parameter |
| | WriteToText(known_args.output)) |
| |
| |
| @beam.ptransform_fn |
| def Count3(pcoll, factor=1): # pylint: disable=invalid-name |
| """Count as a decorated function with a side input. |
| |
| Args: |
| pcoll: the PCollection passed in from the previous transform |
| factor: the amount by which to count |
| |
| Returns: |
| A PCollection counting the number of times each unique element occurs. |
| """ |
| return ( |
| pcoll |
| | 'PairWithOne' >> beam.Map(lambda v: (v, factor)) |
| | beam.CombinePerKey(sum)) |
| |
| |
| def run_count3(known_args, options): |
| """Runs the third example pipeline.""" |
| logging.info('Running third pipeline') |
| with beam.Pipeline(options=options) as p: |
| (p | ReadFromText(known_args.input) |
| | Count3(2) # pylint: disable=no-value-for-parameter |
| | WriteToText(known_args.output)) |
| |
| |
| def get_args(argv): |
| """Determines user specified arguments from the given list of arguments. |
| |
| Args: |
| argv: all arguments. |
| |
| Returns: |
| A pair of argument lists containing known and remaining arguments. |
| """ |
| |
| parser = argparse.ArgumentParser() |
| parser.add_argument('--input', |
| required=True, |
| help='Input file to process.') |
| parser.add_argument('--output', |
| required=True, |
| help='Output file to write results to.') |
| return parser.parse_known_args(argv) |
| |
| |
| def run(argv=None): |
| known_args, pipeline_args = get_args(argv) |
| options = PipelineOptions(pipeline_args) |
| |
| run_count1(known_args, options) |
| run_count2(known_args, options) |
| run_count3(known_args, options) |
| |
| |
| if __name__ == '__main__': |
| logging.getLogger().setLevel(logging.INFO) |
| run() |