Alert if the site goes down by sending an email or slack.

alert.py

#!/usr/bin/env python3.6
# coding=utf-8

from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

import smtplib
import urllib.request
import subprocess
import shlex
import re
import json
import datetime


sites = [
    {'host': 'http://example.com', 'send_email': True, 'send_slack': True, 'test_ping': True, 'test_http': {'status_code': 200, 'contains': 'content body'}},
    {'host': 'http://example.com', 'send_email': False, 'send_slack': True, 'test_ping': True},
]

email = {
    'from': 'webmaster@example.com',
    'to': ['alert@example.com', 'alert2@example.com'],
    'subject': 'Alert',
    'smtp': {
        'host': 'smtp.example.com',
        'port': 587,
        'starttls': True,
        'login': 'webmaster@example.com',
        'password': '123456'
    }
}

#https://api.slack.com/apps//incoming-webhooks
slack_webhook_url = 'https://hooks.slack.com/services/123456/123456/123456'

for site in sites:
    errors = []
    print('Testing the site', site['host'])

    if 'test_ping' in site and site['test_ping'] == True:
        print('Ping test')
        command = "ping -c 1 -w20 {0}".format(site['host'].replace('http://', '').replace('https://', ''))
        p = subprocess.Popen(shlex.split(command), stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        return_code = p.wait()

        if return_code != 0:
            errors.append('Ping')

    if 'test_http' in site:
        print('Http test')
        request = urllib.request.urlopen(site['host'])

        if 'status_code' in site['test_http']:
            if site['test_http']['status_code'] != request.getcode():
                errors.append('Code')

        if 'contains' in site['test_http']:
            if site['test_http']['contains'] not in request.read().decode('utf-8'):
                errors.append('Content')
    
    if errors:
        print("Send errors")
        message = 'Data: {} / Site: {} / Errors: {}'.format(datetime.datetime.now(), site['host'], ','.join(errors))

        if 'send_email' in site and site['send_email'] == True:
            print('Send email')

            msg = MIMEMultipart()
            msg['From'] = email['from']
            msg['To'] = ','.join(email['to'])
            msg['Subject'] = email['subject']
            msg.attach(MIMEText(message, 'plain'))


            server = smtplib.SMTP(email['smtp']['host'], email['smtp']['port'])

            if 'starttls' in email['smtp'] and email['smtp']['starttls'] == True:
                server.starttls()
            
            server.login(email['smtp']['login'], email['smtp']['password'])
            server.send_message(msg)
            server.quit()

        if 'send_slack' in site and site['send_slack'] == True:
            req = urllib.request.Request(slack_webhook_url)
            req.add_header('Content-Type', 'application/json; charset=utf-8')
            jsondata = json.dumps({'text': message})
            jsondataasbytes = jsondata.encode('utf-8')
            req.add_header('Content-Length', len(jsondataasbytes))
            response = urllib.request.urlopen(req, jsondataasbytes)