GCP Dataflow Component Sample

A Kubeflow Pipeline component that prepares data by submitting an Apache Beam job (authored in Python) to Cloud Dataflow for execution. The Python Beam code is run with Cloud Dataflow Runner.

Intended use

Use this component to run a Python Beam code to submit a Cloud Dataflow job as a step of a Kubeflow pipeline.

Runtime arguments

Name Description Optional Data type Accepted values Default
python_file_path The path to the Cloud Storage bucket or local directory containing the Python file to be run. GCSPath
project_id The ID of the Google Cloud Platform (GCP) project containing the Cloud Dataflow job. GCPProjectID
staging_dir The path to the Cloud Storage directory where the staging files are stored. A random subdirectory will be created under the staging directory to keep the job information.This is done so that you can resume the job in case of failure. staging_dir is passed as the command line arguments (staging_location and temp_location) of the Beam code. Yes GCSPath None
requirements_file_path The path to the Cloud Storage bucket or local directory containing the pip requirements file. Yes GCSPath None
args The list of arguments to pass to the Python file. No List A list of string arguments None
wait_interval The number of seconds to wait between calls to get the status of the job. Yes Integer 30

Input data schema

Before you use the component, the following files must be ready in a Cloud Storage bucket:

  • A Beam Python code file.
  • A requirements.txt file which includes a list of dependent packages.

The Beam Python code should follow the Beam programming guide as well as the following additional requirements to be compatible with this component:

  • It accepts the command line arguments --project, --temp_location, --staging_location, which are standard Dataflow Runner options.
  • It enables info logging before the start of a Cloud Dataflow job in the Python code. This is important to allow the component to track the status and ID of the job that is created. For example, calling logging.getLogger().setLevel(logging.INFO) before any other code.

Output

Name Description
job_id The id of the Cloud Dataflow job that is created.

Cautions & requirements

To use the components, the following requirements must be met:

  • Cloud Dataflow API is enabled.
  • The component is running under a secret Kubeflow user service account in a Kubeflow Pipeline cluster. For example:
    component_op(...)
    The Kubeflow user service account is a member of:
  • roles/dataflow.developer role of the project.
  • roles/storage.objectViewer role of the Cloud Storage Objects python_file_path and requirements_file_path.
  • roles/storage.objectCreator role of the Cloud Storage Object staging_dir.

Detailed description

The component does several things during the execution:

  • Downloads python_file_path and requirements_file_path to local files.
  • Starts a subprocess to launch the Python program.
  • Monitors the logs produced from the subprocess to extract the Cloud Dataflow job information.
  • Stores the Cloud Dataflow job information in staging_dir so the job can be resumed in case of failure.
  • Waits for the job to finish.

Setup


In [1]:
project = 'Input your PROJECT ID'
output = 'Input your GCS bucket name' # No ending slash

Install Pipeline SDK


In [2]:
!python3 -m pip install 'kfp>=0.1.31' --quiet

Load the component using KFP SDK


In [3]:
import kfp.components as comp

dataflow_python_op = comp.load_component_from_url(
    'https://raw.githubusercontent.com/kubeflow/pipelines/01a23ae8672d3b18e88adf3036071496aca3552d/components/gcp/dataflow/launch_python/component.yaml')
help(dataflow_python_op)


Help on function Launch Python:

Launch Python(python_file_path:str, project_id:'GCPProjectID', staging_dir:'GCSPath'='', requirements_file_path:'GCSPath'='', args:list='[]', wait_interval:int='30')
    Launch Python
    Launch a self-executing beam python file.

Use the wordcount python sample

In this sample, we run a wordcount sample code in a Kubeflow Pipeline. The output will be stored in a Cloud Storage bucket. Here is the sample code:


In [4]:
!gsutil cat gs://ml-pipeline-playground/samples/dataflow/wc/wc.py


#
# 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.
#

"""A minimalist word-counting workflow that counts words in Shakespeare.

This is the first in a series of successively more detailed 'word count'
examples.

Next, see the wordcount pipeline, then the wordcount_debugging pipeline, for
more detailed examples that introduce additional concepts.

Concepts:

1. Reading data from text files
2. Specifying 'inline' transforms
3. Counting a PCollection
4. Writing data to Cloud Storage as text files

To execute this pipeline locally, first edit the code to specify the output
location. Output location could be a local file path or an output prefix
on GCS. (Only update the output location marked with the first CHANGE comment.)

To execute this pipeline remotely, first edit the code to set your project ID,
runner type, the staging location, the temp location, and the output location.
The specified GCS bucket(s) must already exist. (Update all the places marked
with a CHANGE comment.)

Then, run the pipeline as described in the README. It will be deployed and run
using the Google Cloud Dataflow Service. No args are required to run the
pipeline. You can see the results in your output bucket in the GCS browser.
"""

from __future__ import absolute_import

import argparse
import logging
import re

from past.builtins import unicode

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
from apache_beam.options.pipeline_options import SetupOptions


def run(argv=None):
  """Main entry point; defines and runs the wordcount pipeline."""

  parser = argparse.ArgumentParser()
  parser.add_argument('--input',
                      dest='input',
                      default='gs://dataflow-samples/shakespeare/kinglear.txt',
                      help='Input file to process.')
  parser.add_argument('--output',
                      dest='output',
                      # CHANGE 1/5: The Google Cloud Storage path is required
                      # for outputting the results.
                      default='gs://YOUR_OUTPUT_BUCKET/AND_OUTPUT_PREFIX',
                      help='Output file to write results to.')
  known_args, pipeline_args = parser.parse_known_args(argv)
  # pipeline_args.extend([
  #     # CHANGE 2/5: (OPTIONAL) Change this to DataflowRunner to
  #     # run your pipeline on the Google Cloud Dataflow Service.
  #     '--runner=DirectRunner',
  #     # CHANGE 3/5: Your project ID is required in order to run your pipeline on
  #     # the Google Cloud Dataflow Service.
  #     '--project=SET_YOUR_PROJECT_ID_HERE',
  #     # CHANGE 4/5: Your Google Cloud Storage path is required for staging local
  #     # files.
  #     '--staging_location=gs://YOUR_BUCKET_NAME/AND_STAGING_DIRECTORY',
  #     # CHANGE 5/5: Your Google Cloud Storage path is required for temporary
  #     # files.
  #     '--temp_location=gs://YOUR_BUCKET_NAME/AND_TEMP_DIRECTORY',
  #     '--job_name=your-wordcount-job',
  # ])

  # We use the save_main_session option because one or more DoFn's in this
  # workflow rely on global context (e.g., a module imported at module level).
  pipeline_options = PipelineOptions(pipeline_args)
  pipeline_options.view_as(SetupOptions).save_main_session = True
  with beam.Pipeline(options=pipeline_options) as p:

    # Read the text file[pattern] into a PCollection.
    lines = p | ReadFromText(known_args.input)

    # Count the occurrences of each word.
    counts = (
        lines
        | 'Split' >> (beam.FlatMap(lambda x: re.findall(r'[A-Za-z\']+', x))
                      .with_output_types(unicode))
        | 'PairWithOne' >> beam.Map(lambda x: (x, 1))
        | 'GroupAndSum' >> beam.CombinePerKey(sum))

    # Format the counts into a PCollection of strings.
    def format_result(word_count):
      (word, count) = word_count
      return '%s: %s' % (word, count)

    output = counts | 'Format' >> beam.Map(format_result)

    # Write the output using a "Write" transform that has side effects.
    # pylint: disable=expression-not-assigned
    output | WriteToText(known_args.output)


if __name__ == '__main__':
  logging.getLogger().setLevel(logging.INFO)
  run()

Example pipeline that uses the component


In [5]:
import kfp
import kfp.dsl as dsl
import json
output_file = '{}/wc/wordcount.out'.format(output)
@dsl.pipeline(
    name='Dataflow launch python pipeline',
    description='Dataflow launch python pipeline'
)
def pipeline(
    python_file_path = 'gs://ml-pipeline-playground/samples/dataflow/wc/wc.py',
    project_id = project,
    staging_dir = output,
    requirements_file_path = 'gs://ml-pipeline-playground/samples/dataflow/wc/requirements.txt',
    args = json.dumps([
        '--output', output_file
    ]),
    wait_interval = 30
):
    dataflow_python_op(
        python_file_path = python_file_path, 
        project_id = project_id, 
        staging_dir = staging_dir, 
        requirements_file_path = requirements_file_path, 
        args = args,
        wait_interval = wait_interval)

Submit the pipeline for execution


In [7]:
kfp.Client().create_run_from_pipeline_func(pipeline, arguments={})


Experiment link here
Run link here

Inspect the output


In [ ]:
!gsutil cat $output_file