Copies files to a date centric directory structure based on value of a json field within the file

transform.py

import os, json, shutil
from datetime import datetime

rootdir ='./input'

for subdir, dirs, files in os.walk(rootdir):
    #print(subdir, dirs, files)
    for file in files:
        print(file)
        f=open(subdir + '/'+ file,'r')
        lines=f.readlines()
        json_data = json.loads(lines[0])
        #print(json_data['dateContactWarehoused'])

        date = datetime.strptime(json_data['dateContactWarehoused'], "%Y-%m-%dT%H:%M:%S.%fZ")
        year = str(date.year)
        month = str(date.month)
        day = str(date.day)

        #print(os.getcwd())
        dest_path = os.getcwd() + '/output/' + year + '/' + month + '/' + day + '/'
        os.makedirs(os.path.dirname(dest_path), exist_ok=True)
        shutil.copy2(subdir + '/'+ file, dest_path)

        f.close()