Hetzner DNS records updater using DNS API (dyndns)

hetzner.dyndns.py

import requests
import json
import re
import sys
import os
from datetime import datetime

# --- CONFIGURATION --------------------------------

auth_token   = "YOUR-TOKEN"
zone_name    = "YOUR_TLD"
record_names = ["@"]

# path to temporarily file which holds the last ip
# note: /dev/shm is a virtual filesystem in RAM
tmp_file     = "/dev/shm/public_ip"

# sample crontab which checks public IP each minute
# * * * * * python3 /home/user/hetzner.dyndns.py >> /home/user/dyndns.log 2>&1

# --- END CONFIGURATION ----------------------------

def getPublicIp():
    try:
        response = requests.get(url="http://checkip.dyndns.com/")
        if response.status_code == 200:
            return re.findall(r"[0-9.]+", response.content.decode('utf-8'))[0]
    except requests.exceptions.RequestException:
        print('HTTP Request failed')


def hetznerApi(param, data = None):
    try:
        response = None
        body = {
            "url": "https://dns.hetzner.com/api/v1/"+param,
            "headers": {
                "Auth-API-Token": auth_token,
                "Content-Type": "application/json; charset=utf-8"
            },
            "data": data
        }

        if data == None:
            response = requests.get(**body)
        else:
            response = requests.put(**body)

        if response.status_code == 200:
            return response.content
        else:
            sys.exit(str(response.status_code)
                + ": " + response.content.decode('utf-8'))
    except requests.exceptions.RequestException:
        print('HTTP Request failed')


def getZoneByName(data, name):
    for zone in data["zones"]:
        if zone["name"] == name:
            return zone["id"]
    sys.exit("zone '" + name + "' not found")


def getARecordZoneIdByName(data, name):
    for record in data["records"]:
        if (record["name"] == name) and (record["type"] == "A"):
            return record["id"]
    sys.exit("record '" + name + "' not found")


def updateRecord(zoneId, recordId, name, ip, type="A"):
    data = json.loads(hetznerApi("records/"+recordId, json.dumps({
        "type": type,
        "name": name,
        "value": ip,
        "zone_id": zoneId
    })))["record"]

    if data["value"] == str(ip):
        print(
            name + "." + zone_name + " successfully updated to " + str(ip)
            + "\n    -> last modified: " + data["modified"]
        )

# check if public IP has changed
lastIp = None
pubIp = getPublicIp()
if os.path.exists(tmp_file):
    with open(tmp_file, "r") as f:
        lastIp = f.read()

if lastIp != pubIp:
    with open(tmp_file, "w") as f:
        f.write(pubIp)

    print("-----------------------------------------------")
    print("update: " + datetime.now().strftime("%Y-%m-%d %H:%M:%S"))

    # get zones and find requested zone
    data = json.loads(hetznerApi("zones"))
    zoneId = getZoneByName(data, zone_name)

    # get records of zone
    data = json.loads(hetznerApi("records?zone_id="+zoneId))

    # loop through records and update them
    for record in record_names:
        recordId = getARecordZoneIdByName(data, record)
        updateRecord(zoneId, recordId, record, pubIp)