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How to Check SSL Certificate Expiry in Python
Connect to a host over TLS, extract the certificate's expiry date, and report days remaining using only the Python standard library.
import socket
import ssl
from datetime import datetime
def check_cert_expiry(hostname, port=443):
context = ssl.create_default_context()
with socket.create_connection((hostname, port), timeout=10) as sock:
with context.wrap_socket(sock, server_hostname=hostname) as tls_sock:
cert = tls_soc…How to Add TTL Jitter to Cache Expiration in Python
A Python decorator that adds random jitter to cache TTLs, staggering expiration times to prevent cache avalanche.
import random
import time
from functools import wraps
def add_jitter(ttl: float, jitter_range: float = 0.1) -> float:
"""Add random jitter (as % of TTL) to stagger cache expiration and prevent avalanche."""
jitter = random.uniform(-jitter_range, jitter_range)
return ttl * (1 + jitter)
def cache_with_jitt…How to Handle mTLS Certificate Rotation in Python
Detect mTLS certificate file changes by tracking modification time and hot-reload the SSL context in a running service.
import ssl
import tempfile
import datetime
from pathlib import Path
class MTLSContext:
def __init__(self, cert_path, key_path, ca_path):
self.cert_path = Path(cert_path)
self.key_path = Path(key_path)
self.ca_path = Path(ca_path)
self.context = None
self.last_loaded_mtime …How to Mock mTLS Between Services in Python
Simulate mutual TLS authentication between two services using Python's ssl module with self-signed certificates.
import ssl
import socket
import threading
import tempfile
from pathlib import Path
import subprocess
def create_test_cert(cert_path: Path, key_path: Path, common_name: str = "localhost"):
"""Generate a self-signed certificate using openssl."""
subprocess.run([
"openssl", "req", "-x509", "-newkey", "rs…Enforce TLS 1.2 Minimum in Python
Create an SSL context with a minimum TLS version of 1.2 to enforce secure connections.
import ssl
def get_min_tls_version():
context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
context.minimum_version = ssl.TLSVersion.TLSv1_2
return context.minimum_version
if __name__ == "__main__":
min_version = get_min_tls_version()
print(f"Minimum TLS version set to: {min_version.name} (value: {mi…How to Check Negotiated Cipher Suite in Python
Connect to a TLS server with Python's ssl module and print the negotiated protocol version and cipher suite details.
import ssl
import socket
def get_cipher_suites(hostname, port=443):
context = ssl.create_default_context()
context.set_ciphers("DEFAULT:@SECLEVEL=2")
with socket.create_connection((hostname, port), timeout=5) as sock:
with context.wrap_socket(sock, server_hostname=hostname) as ssock:
…How to Mock a TLS Certificate Rotation Schedule in Python
Simulate a TLS certificate rotation schedule with a Python class that tracks last and next rotation dates and decides when to rotate.
import datetime
import random
import time
class CertRotator:
def __init__(self, cert_name, rotation_days=30):
self.cert_name = cert_name
self.rotation_days = rotation_days
self.last_rotated = datetime.date.today() - datetime.timedelta(days=random.randint(10, 25))
self.next_rotatio…How to Mock an mTLS Client Certificate in Python
Create a self-signed client certificate and key with OpenSSL, load them into an SSL context, and simulate an mTLS handshake in Python for testing.
import ssl
import socket
import subprocess
import tempfile
from pathlib import Path
def create_mock_certificates():
"""Generate self-signed client certificate and key for mTLS testing."""
with tempfile.TemporaryDirectory() as tmpdir:
cert_path = Path(tmpdir) / "client.crt"
key_path = Path(tmpd…How to implement OCSP stapling mock in Python
Simulate OCSP stapling with a caching mechanism that mocks certificate status lookups for TLS handshake validation.
import hashlib
import time
class OCSPStapler:
def __init__(self, cert_serial: str, issuer_hash: str):
self.cert_serial = cert_serial
self.issuer_hash = issuer_hash
self.cache = {}
def _mock_query_ocsp(self, serial: str) -> dict:
"""Simulate OCSP responder lookup."""
di…How to Mock an Ingress TLS Certificate Manager in Python
Build a mock TLS certificate manager for ingress that issues, checks, and renews certificates with expiry tracking — useful for testing deployment workflows before touching real infrastructure.
import ssl
import socket
from datetime import datetime, timedelta
class TLSCertManager:
def __init__(self, hostname):
self.hostname = hostname
self.certificates = {}
def request_certificate(self, domain, days_valid=90):
"""Mock a certificate issuance request that stores a cert with e…Browse by section
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