def main():
try:
client = MongoClient('localhost',27017)
DataService.init(client)
apps = DataService.retrieve_appinfo()
#work flow
for app in apps.keys():
user_download_history = DataService.retrieve_user_download_history()
top_5_app = calculate_Top_5(app, user_download_history.values())
DataService.update_app_info({"app_id": app},{"$set": {"Top 5": top_5_app}})
except Exception as e:
print(e)
finally:
#clean up work
if 'client' in locals():
client.close()
