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Python Code Samples

Copy-ready Python snippets by topic and difficulty — short, focused, and runnable in the browser editor.

275 matches
Auth & security at scale medium

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.

mtls ssl certificates
Python
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…
15 0 Open
Auth & security at scale medium

How to Test X-Content-Type-Options nosniff in Python with Mocks

Mock httpx responses and verify that a server's X-Content-Type-Options header includes nosniff to prevent MIME sniffing.

security httpx mocking
Python
import httpx
from unittest.mock import Mock, patch

def fetch_headers(url: str) -> dict:
    response = httpx.get(url)
    return dict(response.headers)

def mock_nosniff_check(response) -> bool:
    content_type = response.headers.get("content-type", "")
    x_content_type_options = response.headers.get("x-content-ty…
14 0 Open
Production deployment patterns easy

How to Create a Liveness Probe HTTP Mock in Python

Build a lightweight HTTP server in Python that mimics a Kubernetes-style liveness endpoint, returning JSON health status for local testing.

http healthcheck mock-server
Python
import http.server
import threading
import time


class LivenessHandler(http.server.BaseHTTPRequestHandler):
    def do_GET(self):
        if self.path == "/healthz":
            self.send_response(200)
            self.send_header("Content-Type", "application/json")
            self.end_headers()
            self.wfi…
16 0 Open
Production deployment patterns medium

How to Mock Kubernetes Secret Mounts in Python

Create and inspect a mock Kubernetes secret volume mount using the official client library and unittest.mock.

kubernetes mock testing
Python
import json
from kubernetes import client, config, watch
from unittest.mock import Mock, patch

def create_mock_mount_spec():
    """Create a mock Kubernetes secret volume mount."""
    mock_client = Mock()
    mock_client.api_version = "v1"
    mock_client.kind = "Secret"
    mock_client.metadata = {"name": "my-secre…
15 0 Open
Production deployment patterns medium

How to Mock Kubernetes Services with a ClusterIP Registry in Python

Simulate Kubernetes service discovery by assigning ClusterIP addresses to dataclass-defined services, with JSON export for inspection or testing.

kubernetes clusterip mock
Python
import json
from dataclasses import dataclass, asdict
from typing import Dict, Optional


@dataclass
class Service:
    name: str
    namespace: str
    cluster_ip: str
    selector: Dict[str, str]
    port: int
    target_port: Optional[int] = None


class ClusterIPServiceRegistry:
    _ip_counter = 0

    def __init…
14 0 Open
Production deployment patterns easy

How to Mock a Container Registry in Python

Build an in-memory container registry mock with push, tag listing, and manifest retrieval logic for testing deployment tooling.

containers testing mocking
Python
import json
from collections import defaultdict


class MockRegistry:
    def __init__(self):
        self.repositories = defaultdict(dict)

    def push_image(self, repo: str, tag: str, layers: list[str]) -> None:
        self.repositories[repo][tag] = {
            "layers": layers,
            "size": sum(len(layer…
15 0 Open
Production deployment patterns easy

How to Mock a Dependency for Readiness Probe in Python

Use unittest.mock.Mock to simulate a dependency's readiness check response for testing a service's is_ready method without hitting a real connection.

unittest.mock mock readiness probe
Python
import time
import unittest
from unittest.mock import Mock

class Service:
    def __init__(self, dependency):
        self.dependency = dependency

    def is_ready(self):
        try:
            result = self.dependency.check()
            return result == "ready"
        except Exception:
            return False
…
18 0 Open
Production deployment patterns easy

How to Mock a Slow Startup Probe for Fast Testing in Python

This code shows how to replace a slow startup probe's initialization with a mock to make tests run fast and reliably.

mock testing startup-probe
Python
import time
from unittest.mock import Mock, patch


class StartupProbe:
    def __init__(self, init_time):
        self.init_time = init_time
        self.ready = False

    def initialize(self):
        time.sleep(self.init_time)
        self.ready = True
        return self.ready


def run_startup_probe(probe):
    …
16 0 Open
Production deployment patterns easy

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.

tls certificates ingress
Python
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…
16 0 Open
Production deployment patterns medium

How to mock S3 remote backend for Terraform in Python

Simulate a Terraform S3 remote backend using moto to write and read state files, enabling local testing without real AWS.

boto3 moto terraform
Python
import boto3
from moto import mock_aws
import json
from pathlib import Path

@mock_aws
def demo_s3_remote_backend():
    s3 = boto3.client("s3", region_name="us-east-1")
    bucket = "terraform-state-bucket"
    key = "env/prod/terraform.tfstate"
    
    s3.create_bucket(Bucket=bucket)
    
    # Simulate Terraform w…
15 0 Open
Production deployment patterns medium

Mock ConfigMap Mount Environment Variables in Python

Simulate reading environment variables from a Kubernetes ConfigMap-mounted directory and test it with mocks.

kubernetes configmap mocking
Python
import os
import tempfile
from unittest.mock import patch

def load_config_from_mount(mount_path):
    """Simulate reading environment variables from a ConfigMap-mounted directory."""
    config = {}
    for filename in os.listdir(mount_path):
        file_path = os.path.join(mount_path, filename)
        if os.path.i…
16 0 Open

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