ping.py

#!/usr/bin/env python3

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### NZBGET API SCRIPT                                                        ###
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# Ping script by ssnjr for heroku.
#
# Checks if server is in standby or not, and pings if it isn't in standby.
#
# Server is in standby when there are no downloads in progress (server paused 
# or all jobs completed).
#
# A web dyno sleeps if it doesn't receive any traffic within 30 mins so the 
# script pings every 30 minutes when the server is not in standby to prevent 
# nzbget from dying during an ongoing process.
#
# To save dyno hours the script doesn't ping when server is in standby i.e. 
# when it is not in use.
#
# The script can keep an instance alive for 24 hrs.

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### NZBGET API SCRIPT                                                        ###
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import os
import re
import sys
import requests
from time import sleep
from xmlrpc.client import ServerProxy

host = '127.0.0.1'
port = os.environ.get('PORT')
username = os.environ.get('CTRL_USERNAME')
password = os.environ.get('CTRL_PASS')
app_url = os.environ.get('APP_URL')

# Build an URL for XML-RPC requests
rpcUrl = f'http://{username}:{password}@{host}:{port}/xmlrpc'
server = ServerProxy(rpcUrl)  # Create remote server object

def ping():
    try:
        response = requests.get(app_url)
        response_time = int(response.elapsed.total_seconds()*1000)
        message = f'PING: {response.url} - ' + \
                  f'pinged sucessfully ({response_time}ms)'
        server.writelog('INFO', message)
    except:
        message = f'Can\'t ping "{app_url}" please ensure the app url ' + \
                   'is entered in correctly'
        server.writelog('ERROR', message)

while True:
    sleep(1798)

    # Fetches bool Status for the following:
    ServerStandBy = server.status()['ServerStandBy']
    DownloadPaused = server.status()['DownloadPaused']

    # Pings the server if server is not in standby or if download is paused:
    if not ServerStandBy or DownloadPaused:
        ping()

    # Opposite of the above condition:
    elif ServerStandBy and not DownloadPaused:
        server.writelog('INFO', 'Server is in standby')