Find missing files, given a range of dates and a file template

find-missing-files.py

#!/usr/bin/env python

from datetime import date, datetime, timedelta
import os
import sys
import jinja2

script_name = os.path.basename(__file__)

def usage():

    print('{} [START-DATE] [END-DATE] [FILE-TEMPLATE]'.format(script_name))
    print('')
    print('  where:')
    print('')
    print('    START-DATE     start date (YYYYMMDD)')
    print('    END-DATE       end date (YYYYMMDD)')
    print('    FILE-TEMPLATE  file template (use {yyyy}, {mm}, and {dd})')
    print('')
    print('  For example:')
    print('')
    print('    {} 20140101 20141231 /data/{{{{yyyy}}}}/{{{{mm}}}}/{{{{dd}}}}/data-file-{{{{yyyy}}}}{{{{mm}}}}{{{{dd}}}}.txt'.format(script_name))
    print('')

def main():

    try:
        start_date = sys.argv[1]
        end_date = sys.argv[2]
        file_template = sys.argv[3]
    except IndexError:
        usage()
        sys.exit(2)

    start_date_obj = datetime.strptime(start_date, '%Y%m%d')
    end_date_obj = datetime.strptime(end_date, '%Y%m%d')

    date_list = [(start_date_obj + timedelta(days=i)).strftime('%Y%m%d') for i in range((end_date_obj - start_date_obj).days + 1)]

    none_missing = True
    for date in date_list:
        kwargs = {'yyyy': date[0:4], 'mm': date[4:6], 'dd': date[6:8]}
        file = jinja2.Template(os.path.expandvars(file_template)).render(**kwargs)
        if not os.path.isfile(file):
            none_missing = False
            print('Missing file: {}'.format(file))

    if none_missing:
        print('No missing files...')

if __name__ == '__main__':
    main()