#
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# 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
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"""A word-counting workflow."""
from __future__ import absolute_import
import argparse
import logging
import time
import apache_beam as beam
from apache_beam.metrics import Metrics
from apache_beam.options.pipeline_options import PipelineOptions
from apache_beam.options.pipeline_options import SetupOptions
from apache_beam.options.pipeline_options import StandardOptions
SLEEP_TIME_SECS = 1
_LOGGER = logging.getLogger()
[docs]class StreamingUserMetricsDoFn(beam.DoFn):
"""Generates user metrics and outputs same element."""
def __init__(self):
self.double_message_counter = Metrics.counter(self.__class__,
'double_msg_counter_name')
self.msg_len_dist_metric = Metrics.distribution(
self.__class__, 'msg_len_dist_metric_name')
[docs] def start_bundle(self):
time.sleep(SLEEP_TIME_SECS)
[docs] def process(self, element):
"""Returns the processed element and increments the metrics."""
text_line = element.strip()
self.double_message_counter.inc()
self.double_message_counter.inc()
self.msg_len_dist_metric.update(len(text_line))
_LOGGER.debug("Done processing returning element array: '%s'", element)
return [element]
[docs] def finish_bundle(self):
time.sleep(SLEEP_TIME_SECS)
[docs]def run(argv=None):
"""Given an initialized Pipeline applies transforms and runs it."""
parser = argparse.ArgumentParser()
parser.add_argument(
'--output_topic', required=True,
help=('Output PubSub topic of the form '
'"projects/<PROJECT>/topic/<TOPIC>".'))
group = parser.add_mutually_exclusive_group(required=True)
group.add_argument(
'--input_topic',
help=('Input PubSub topic of the form '
'"projects/<PROJECT>/topics/<TOPIC>".'))
group.add_argument(
'--input_subscription',
help=('Input PubSub subscription of the form '
'"projects/<PROJECT>/subscriptions/<SUBSCRIPTION>."'))
known_args, pipeline_args = parser.parse_known_args(argv)
pipeline_options = PipelineOptions(pipeline_args)
pipeline_options.view_as(SetupOptions).save_main_session = True
pipeline_options.view_as(StandardOptions).streaming = True
pipeline = beam.Pipeline(options=pipeline_options)
_ = (pipeline
| beam.io.ReadFromPubSub(subscription=known_args.input_subscription)
| 'generate_metrics' >> (beam.ParDo(StreamingUserMetricsDoFn()))
| 'dump_to_pub' >> beam.io.WriteToPubSub(known_args.output_topic))
result = pipeline.run()
result.wait_until_finish()
return result
if __name__ == '__main__':
logging.getLogger().setLevel(logging.INFO)
run()