i want to log some information of every single request send to a busy http server in a formatted form,use log module would create some thing i don't want to: [I 131104 15:31:29 Sys:34] i think of csv format but i don't know how to customize it,and python got csv module,but read the manual import csv with open('some.csv', 'w', newline='') as f: writer = csv.writer(f) writer.writerows(someiterable) since it would open and close a file each time, i am afraid in this way would slow down the whole server performance, what could i do?