A Python script using Requests to time downloads

time_download.py

#!/usr/bin/env python3
# time_download.py
# A simple script to time downloads in order to determine
#   variances in the speed of the network connection used
#   by the sensor machine. Reports in CSV
# YOU NEED TO CHANGE THE TARGET_URI VARIABLE
# Please, please, please don't use my cdn for more than a few downloads.
# You will end up getting your IP blocked.

import requests 
import datetime 
from time import perf_counter, sleep
from sys import argv 

TARGET_URI = "http://<invalid>cdn.silverwingedseraph.net/randombits.bin"

if len(argv) != 3:
	print("Wrong number of arguments; "
        "give only a target file and an interval in seconds.")
	exit(1)

try:
    duration = float(argv[2])
except ValueError:
    print("Duration must be a valid float.")

if duration < 10:
    print("[ERROR]: duration less than 10 seconds is highly discouraged.")
    exit(1)
elif duration < 60:
    print("[WARNING]: duration less than 1 minute may cause a load problem" 
            " on the remote server.")
    sleep(3)


print("[INFO]: Beginning data collection at {}".format(datetime.datetime.now()))
while (1):
	t0 = perf_counter()
	r = requests.get(TARGET_URI)
	t1 = perf_counter()
	now = datetime.datetime.now()
	data = "{},{}\n".format(now, t1 - t0)
	with open(argv[1], "a") as f:
		f.write(data)
	print("Wrote: " + data, end="")
	sleep(duration)