dns_lowest_latency_checker.py

"""
This hacky-hacky script checks what's the lowest latency IP for a given DNS resource
"""

import subprocess

COUNT = "3"
res = []

hostname = "MY.DNSDOMAIN.COM"
result = subprocess.run(['dig', '+short', hostname], stdout=subprocess.PIPE)
ips = list(result.stdout.decode("utf-8").replace("\\n", " ").split())
print(ips)

for host in ips:
    ping = subprocess.run(['ping', '-c', COUNT, host], stdout=subprocess.PIPE)

    if ping.returncode != 0:
        # host is down
        continue

    ping_time = ping.stdout.decode("utf-8")
    ping_time = ping_time.split("round-trip min/avg/max/stddev =")[1].split()[0]
    # e.g: 123.775/133.417/144.147/8.352

    # 0: min
    # 1: avg
    # 2: max
    # 3: stddev
    ping_time = ping_time.split("/")[1]
    # e.g: '143.135'
    res.append((host,ping_time))

_min = min(res, key=lambda x: float(x[1]))
print(_min[0])