How to Integrate Replit with Let's Encrypt

1// check-certs.js — SSL certificate expiry checker
2const tls = require('tls');
3
4function checkCertExpiry(hostname, port = 443) {
5  return new Promise((resolve, reject) => {
6    const socket = tls.connect({ host: hostname, port, servername: hostname }, () => {
7      const cert = socket.getPeerCertificate();
8      socket.destroy();
9
10      if (!cert || !cert.valid_to) {
11        return reject(new Error(`No certificate found for ${hostname}`));
12      }
13
14      const expiryDate = new Date(cert.valid_to);
15      const now = new Date();
16      const daysRemaining = Math.floor((expiryDate - now) / (1000 * 60 * 60 * 24));
17
18      resolve({
19        hostname,
20        subject: cert.subject?.CN || hostname,
21        issuer: cert.issuer?.O || 'Unknown',
22        expiryDate: expiryDate.toISOString(),
23        daysRemaining,
24        isExpired: daysRemaining < 0,
25        isExpiringSoon: daysRemaining < 30
26      });
27    });
28
29    socket.on('error', reject);
30    socket.setTimeout(10000, () => {
31      socket.destroy();
32      reject(new Error(`Timeout connecting to ${hostname}:${port}`));
33    });
34  });
35}
36
37async function checkAllDomains(domainsEnv) {
38  const domains = (domainsEnv || 'example.com').split(',').map(d => d.trim());
39  const results = [];
40
41  for (const domain of domains) {
42    try {
43      const result = await checkCertExpiry(domain);
44      results.push(result);
45      const status = result.isExpired ? 'EXPIRED' : result.isExpiringSoon ? 'EXPIRING SOON' : 'OK';
46      console.log(`[${status}] ${domain} — ${result.daysRemaining} days remaining (expires ${result.expiryDate})`);
47    } catch (err) {
48      console.error(`[ERROR] ${domain}: ${err.message}`);
49      results.push({ hostname: domain, error: err.message });
50    }
51  }
52
53  return results;
54}
55
56const DOMAINS = process.env.DOMAINS || 'example.com,google.com';
57checkAllDomains(DOMAINS)
58  .then(results => {
59    const alerts = results.filter(r => r.isExpiringSoon || r.isExpired || r.error);
60    if (alerts.length > 0) {
61      console.log('\nAlerts requiring attention:');
62      alerts.forEach(a => console.log(' -', a.hostname, a.error || `expires in ${a.daysRemaining} days`));
63      process.exit(1);  // Non-zero exit signals failure in Replit Scheduled jobs
64    }
65  })
66  .catch(console.error);

1# check_certs.py — SSL certificate expiry checker with Slack alerts
2import os
3import ssl
4import socket
5import datetime
6import json
7import requests
8
9def check_cert_expiry(hostname, port=443):
10    context = ssl.create_default_context()
11    try:
12        with socket.create_connection((hostname, port), timeout=10) as sock:
13            with context.wrap_socket(sock, server_hostname=hostname) as ssock:
14                cert = ssock.getpeercert()
15    except Exception as e:
16        return {'hostname': hostname, 'error': str(e)}
17
18    # cert['notAfter'] format: 'Mar 15 12:00:00 2025 GMT'
19    expiry_str = cert.get('notAfter', '')
20    expiry_date = datetime.datetime.strptime(expiry_str, '%b %d %H:%M:%S %Y %Z')
21    days_remaining = (expiry_date - datetime.datetime.utcnow()).days
22
23    return {
24        'hostname': hostname,
25        'expiry_date': expiry_date.isoformat(),
26        'days_remaining': days_remaining,
27        'is_expired': days_remaining < 0,
28        'is_expiring_soon': days_remaining < int(os.environ.get('ALERT_DAYS_THRESHOLD', 30))
29    }
30
31def send_slack_alert(domains_at_risk):
32    webhook_url = os.environ.get('ALERT_WEBHOOK_URL')
33    if not webhook_url or not domains_at_risk:
34        return
35    message = 'SSL Certificate Alerts:\n' + '\n'.join(
36        f"- {d['hostname']}: {d.get('days_remaining', 'ERROR')} days remaining or error: {d.get('error', '')}" 
37        for d in domains_at_risk
38    )
39    requests.post(webhook_url, json={'text': message}, timeout=10)
40
41def main():
42    domains_env = os.environ.get('DOMAINS', 'example.com')
43    domains = [d.strip() for d in domains_env.split(',')]
44    results = []
45
46    for domain in domains:
47        result = check_cert_expiry(domain)
48        results.append(result)
49        if result.get('error'):
50            print(f'[ERROR] {domain}: {result["error"]}')
51        else:
52            status = 'EXPIRED' if result['is_expired'] else ('EXPIRING SOON' if result['is_expiring_soon'] else 'OK')
53            print(f'[{status}] {domain} — {result["days_remaining"]} days remaining')
54
55    alerts = [r for r in results if r.get('is_expiring_soon') or r.get('is_expired') or r.get('error')]
56    if alerts:
57        send_slack_alert(alerts)
58        print(f'\n{len(alerts)} alert(s) sent.')
59
60if __name__ == '__main__':
61    main()