Convert Lighthouse 4 JSON audit file to a common log format and append the results to it each time it runs

logify.py

import json
import argparse
import io
import sys

def get_args():
    example_text = '''
    examples:

    python3 ./logify.py --input-file='foo.json'

    lighthouse https://cats.com --only-categories=accessibility --output='json' | python3 ./logify.py --input-file='-' >> logified-lighthouse.log

    '''

    parser = argparse.ArgumentParser()
    parser.add_argument('-i', '--input-file', help='Path to your JSON file. To specify stdin, use a dash "-" or omit argument.', default="-")
    return parser.parse_args()


def filter_audits(x, data, keepers):
    """ Return only audits with metrics """
    if data['audits'][x]['scoreDisplayMode'] == 'error':
        keepers['audit__' + x] = 0
    elif data['audits'][x]['scoreDisplayMode'] == 'notApplicable':
        keepers['audit__' + x] = 1
    elif data['audits'][x]['scoreDisplayMode'] != ('manual' or 'informative'):
        keepers['audit__' + x] = data['audits'][x]['score']
    return keepers


def convert_to_log(data):
    """ Convert JSON to log freindly format """
    dataToLog = data['fetchTime'] + ' '
    interesting_keys = ['lighthouseVersion', 'requestedUrl', 'finalUrl']
    keepers = {x: data[x] for x in interesting_keys if x in data}
    for x in data['categories']:
        keepers['total__' + x + '_score'] = data['categories'][x]['score']
    for x in data['audits']:
        filter_audits(x, data, keepers)
    for key, value in keepers.items():
        key = key.replace('-','_')
        dataToLog += '%s=%s' % (key, repr(value) + ' ')
    return dataToLog


def read_input(input_file):
    """ Read Lighthouse JSON file  """
    if type(input_file) is str:
        with io.open(input_file, encoding='utf-8') as stream:
            return json.JSONDecoder().decode(stream.read())
    else:
        return json.JSONDecoder().decode(input_file.read())


def main():
    """ Get data and print log """
    args = get_args()
    if args.input_file == '-':
        data = json.load(sys.stdin, encoding='utf-8')
    else:
        data = read_input(args.input_file)

    print(convert_to_log(data))


if __name__ == '__main__':
    main()