Use Dataflow to count top imported packages in Java

top_java_import.py

#!/usr/bin/env python

"""
Copyright Google Inc. 2016
Licensed 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.
"""

import apache_beam as beam
import argparse

def startsWith(line, term):
    if line.startswith(term):
        yield line

def splitPackageName(packageName):
    """e.g. given com.example.appname.library.widgetname
            returns com
	            com.example
                    com.example.appname
       etc.
    """
    result = []
    end = packageName.find('.')
    while end > 0:
        result.append(packageName[0:end])
        end = packageName.find('.', end+1)
    result.append(packageName)
    return result

def getPackages(line, keyword):
    start = line.find(keyword) + len(keyword)
    end = line.find(';', start)
    if start < end:
        packageName = line[start:end].strip()
        return splitPackageName(packageName)
   return []

def packageUse(line, keyword):
    packages = getPackages(line, keyword)
    for p in packages:
        yield (p, 1)

def by_value(kv1, kv2):
    key1, value1 = kv1
    key2, value2 = kv2
    return value1 < value2

PROJECT='test-hamdi'
BUCKET='hamdi-coursera-labs'

def run():
    pipeline_args = [
        '--project={0}'.format(PROJECT),
        '--job_name=topimport',
        '--save_main_session',
        '--staging_location=gs://{0}/staging/'.format(BUCKET),
        '--temp_location=gs://{0}/staging/'.format(BUCKET),
        '--runner=DataflowRunner'
    ]
 
    p = beam.Pipeline(argv=pipeline_args)

    input = 'gs://{0}/top-import/*.java'.format(BUCKET)
    output_prefix = 'gs://{0}/top-import/output'.format(BUCKET)
    keyword = 'import'

    # find most used packages
    (p
        | 'GetJava' >> beam.io.ReadFromText(input)
        | 'GetImports' >> beam.FlatMap(lambda line: startsWith(line, keyword))
        | 'PackageUse' >> beam.FlatMap(lambda line: packageUse(line, keyword))
        | 'TotalUse' >> beam.CombinePerKey(sum)
        | 'Top_5' >> beam.transforms.combiners.Top.Of(5, by_value)
        | 'write' >> beam.io.WriteToText(output_prefix)
    )

    p.run()

if __name__ == '__main__':
    run()