Change the default GW of a zcube encoder as the network changes.

zcube_gw.py

#!/usr/bin/python
# -*- coding: utf-8 -*-

"""
A garbage hacky script to automatically reconfigure the default gateway of the zcube video encoder
based on which network route is available.
Preferance is given to one link!
Must be run as root! - This might not be true anymore... /shrug
"""

import time
import os
import datetime
import requests
import subprocess
import json

encoder = ''
los_gw = ''
satcom_gw = ''  # Hub Router
gateways = [los_gw, satcom_gw]
preferred_gw = satcom_gw

requests_timeout = 5
cycle_time = 15  # var so we can adjust if the zcube reboots slower


def ping(target):
    """
    Returns a boolean if the target responds to a ping
    """

    fnull = open(os.devnull, 'w')
    result = subprocess.run(['ping', '-c', '4', target], stdout=fnull,
                            stderr=fnull).returncode
    fnull.close()
    return result == 0


def reconfigure(new_gw):
    """
    Reconfigure the ZCube encoder to use the new default gateway
    """

    # Set the headers once
    headers = {
        'Origin': 'http://' + encoder,
        'Accept': 'application/json, text/javascript, */*; q=0.01',
        'X-Requested-With': 'XMLHttpRequest',
        'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:81.0) Gecko/20100101 Firefox/81.0',
        'Connection': 'close',
        'Referer': 'http://' + encoder + '/',
        'Accept-Language': 'en-US,en;q=0.5',
        'Accept-Encoding': 'gzip, deflate',
        'DNT': '1',
        'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8',
    }

    session = requests.Session()

    try:
        # Send the change
        params_post = {
            'local_ip': encoder,
            'use_dhcp': '0',
            'local_dnsip2': '8.8.4.4',
            'do_autostart': '1',
            'local_dnsip': '8.8.8.8',
            'local_netmask': '255.255.255.0',
            'enc_adv_setting': 'on',
            'action': 'SetIp',
            'ipmtu': '1500',
            'default_gw': new_gw,
        }
        response = session.post('http://' + encoder + '/cgi-bin/control.cgi',
                                data=params_post, headers=headers, timeout=requests_timeout)
        if response.status_code != 200:
            print(datetime.datetime.now(), "-  Reconfiguring didn't work for some reason! Status Code:",
                  response.status_code)

        # Save the change
        params_post = {'action': 'SaveUser', 'enc_current_preset': 'encoder'}
        response = session.post('http://' + encoder + '/cgi-bin/control.cgi',
                                data=params_post, headers=headers, timeout=requests_timeout)
        if response.status_code != 200:
            print(datetime.datetime.now(), "-  Saving didn't work for some reason! Status Code:",
                  response.status_code)

        # Reboot the device
        params_post = {'action': 'RestartBoard'}
        response = session.post('http://' + encoder + '/cgi-bin/control.cgi',
                                data=params_post, headers=headers, timeout=requests_timeout)
        if response.status_code != 200:
            print(datetime.datetime.now(), response.status_code,
                  "-  Unable to restart the encoder for some reason! Status Code:")
    except requests.exceptions.RequestException as e:
        print(datetime.datetime.now(), "-  Reconfiguring did not work for some reason!", e)
        time.sleep(cycle_time)


if __name__ == '__main__':

    while True:
        # Figure out what the current default_gw is
        current_gw = ''
        while not current_gw:
            try:
                system_request = requests.get('http://' + encoder
                                              + '/cgi-bin/control.cgi?ctrl=sys&chn=', timeout=requests_timeout)
                json_values = \
                    json.loads(system_request.content.decode('utf-8'))
                current_gw: str = json_values['default_gw']
                other_gw: str = [x for x in gateways if x != current_gw][0]
            except requests.exceptions.RequestException as e:
                # The encoder is likely still booting up
                time.sleep(5)
                pass

        # Ensure the current GW is available, check and swap to preferred GW if needed.
        while True:
            if ping(current_gw):
                if current_gw == preferred_gw:
                    # Already at preferred GW, and preferred GW is up
                    time.sleep(cycle_time)
                else:
                    if ping(preferred_gw):
                        print(datetime.datetime.now(),
                              '-  Preferred Link Reestablished - Reconfiguring ZCube Encoder...')
                        reconfigure(preferred_gw)
                        time.sleep(cycle_time)
                        break
            else:
                print(datetime.datetime.now(),
                      '-  {} Link Lost!'.format(current_gw))
                # See if the other route is up
                if ping(other_gw):
                    print(datetime.datetime.now(),
                          '-  {} Link Detected - Reconfiguring ZCube Encoder...'.format(other_gw))
                    reconfigure(other_gw)
                    time.sleep(cycle_time)
                    break
                else:
                    print(datetime.datetime.now(),
                          '-  NO active link detected! trying again after a short while...')
                    time.sleep(cycle_time)