foo.python3

#!/usr/bin/python3

import urllib.request
import time
import apt_pkg
import subprocess
import sys


def get_ping(cdn):
    """Return average over 5 RTT measurements"""
    with subprocess.Popen(
        ["ping", "-q", "-c", "5", f"cdn-{cdn}.deb.debian.org"],
        stdout=subprocess.PIPE,
        encoding="utf-8",
    ) as proc:
        for line in proc.stdout:
            if line.startswith("rtt"):
                return float(line.split("=")[1].split("/")[1])


def get_speed(cdn):
    """Return the speed of the CDN, in Mbit/s"""
    start = time.time()
    fetched = 0
    with urllib.request.urlopen(
        f"http://cdn-{cdn}.deb.debian.org/debian/pool/main/m/mysql-8.0/mysql-testsuite-8.0_8.0.21-1_amd64.deb"
    ) as fobj:
        while True:
            block = fobj.read(10 * 1024 * 1024)
            if not block:
                break

            fetched += len(block)
            elapsed = time.time() - start

            if "-q" not in sys.argv:
                print(80 * " ", end="\r", file=sys.stderr)
                print(
                    f"{cdn}: {apt_pkg.size_to_str(fetched/elapsed * 8) } bit/s",
                    end="\r",
                    file=sys.stderr,
                )

    return start, fetched / elapsed / (1000 * 1000) * 8


def main():
    """Main entry point."""
    cdn_names = ["aws", "fastly"]
    results = {}
    first = time.time()
    for cdn in cdn_names:
        ts0, speed0 = get_speed(cdn)
        if "-q" not in sys.argv:
            print(file=sys.stderr)
        ts1, speed1 = get_speed(cdn)

        if "-q" not in sys.argv:
            print(file=sys.stderr)
        print(ts0, cdn, speed0, sep=",")

        past_speeds = [speed0]
        while (
            all(speed1 > 1.1 * s or speed1 < 0.9 * s for s in past_speeds)
            and len(past_speeds) < 5
        ):
            past_speeds.append(speed1)
            print(ts1, cdn, speed1, sep=",")
            ts1, speed1 = get_speed(cdn)
        if len(past_speeds) > 1:
            print(ts1, cdn, speed1, sep=",")

    if "-q" not in sys.argv:
        print(file=sys.stderr)


if __name__ == "__main__":
    main()