Source code for apache_beam.runners.dataflow.dataflow_exercise_streaming_metrics_pipeline

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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()