Certificate Expiry Calculator

import ssl
import socket
from datetime import datetime, timezone

def get_cert_expiry(hostname: str, port: int = 443) -> dict:
    """Fetch TLS certificate expiry info for a hostname."""
    context = ssl.create_default_context()
    with socket.create_connection((hostname, port), timeout=5) as sock:
        with context.wrap_socket(sock, server_hostname=hostname) as ssock:
            cert = ssock.getpeercert()

    not_after = datetime.strptime(cert['notAfter'], '%b %d %H:%M:%S %Y %Z')
    not_after = not_after.replace(tzinfo=timezone.utc)
    now = datetime.now(timezone.utc)
    days_remaining = (not_after - now).days

    return {
        "hostname": hostname,
        "expires": not_after.strftime('%Y-%m-%d'),
        "days_remaining": days_remaining,
        "status": "expired" if days_remaining < 0
                  else "critical" if days_remaining < 14
                  else "warning" if days_remaining < 30
                  else "good",
        "subject": dict(x[0] for x in cert.get('subject', [])),
        "issuer": dict(x[0] for x in cert.get('issuer', [])),
    }

# Example
result = get_cert_expiry("example.com")
print(f"Expires: {result['expires']}")
print(f"Days remaining: {result['days_remaining']}")
print(f"Status: {result['status']}")