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How to Build a Mock Route53 DNS API in Python
Create a mock DNS API server in Python that simulates Route53 record lookups and updates using the standard library.
import json
from http.server import BaseHTTPRequestHandler, HTTPServer
from urllib.parse import urlparse, parse_qs
class DNSUpdateHandler(BaseHTTPRequestHandler):
records = {"example.com": "1.2.3.4"}
def do_GET(self):
domain = parse_qs(urlparse(self.path).query).get("domain", [""])[0]
if dom…How to Implement a Weighted DNS Resolver with Failover in Python
Simulates a weighted DNS load balancer that distributes traffic across IPs by weight and automatically fails over when a server is marked unhealthy.
import random
import time
class WeightedDNSResolver:
def __init__(self, records):
self.records = records # list of (ip, weight)
self.total_weight = sum(weight for _, weight in records)
self.failed_ips = set()
def resolve(self):
available = [(ip, weight) for ip, weight in self…How to Perform a DNS Lookup for A Records in Python
Resolve a hostname to IPv4 A records using Python's built-in socket.getaddrinfo and return a sorted list of addresses.
import socket
def get_a_records(hostname):
"""Fetch A records (IPv4 addresses) for a given hostname."""
try:
# getaddrinfo with family AF_INET restricts to IPv4 (A records)
infos = socket.getaddrinfo(hostname, None, socket.AF_INET)
# Each info tuple: (family, type, proto, canonname, so…Mock Route53 change_resource_record_sets in Python
This code demonstrates how to mock AWS Route53 change_resource_record_sets API calls using the botocore Stubber, allowing you to test DNS update logic without touching real infrastructure.
import boto3
from botocore.exceptions import ClientError
def mock_change_resource_record_sets():
"""Demonstrates Route53 change_resource_record_sets with a mock client."""
# Create a mock Route53 client
route53 = boto3.client('route53', region_name='us-east-1',
aws_access_key_id…How to Create a TCP DNS Mock Server in Python
This code creates a mock TCP DNS server that listens on a specified port, accepts probe connections, and returns a fixed DNS response header to simulate a live DNS service for testing and observability.
import socket
import threading
def handle_client(client_socket, address):
print(f"[+] Connection from {address}")
try:
while True:
data = client_socket.recv(1024)
if not data:
break
print(f"[*] Received {len(data)} bytes (TCP DNS probe)")
…ACME LetsEncrypt Mock Challenge Server in Python
A minimal HTTP server that serves key authorizations for ACME/Let's Encrypt DNS-01 or HTTP-01 challenges during testing and validation.
from http.server import HTTPServer, BaseHTTPRequestHandler
import json
# In-memory store simulating the ACME challenge token -> key authorization pair
challenge_store = {
"token_example": "token_example.key_authorization"
}
class AcmeChallengeHandler(BaseHTTPRequestHandler):
def do_GET(self):
# Extra…How to mock DNS CAA record lookups in Python
Parse and filter DNS CAA records with a mock lookup function, demonstrating how certificate authorities validate domain authorization.
import dnslib
def parse_caa_record(record_string):
"""Parse a DNS CAA record string into its components."""
parts = record_string.split()
flags = int(parts[0])
tag = parts[1]
value = parts[2]
return flags, tag, value
def mock_caa_lookup(domain, caa_records):
"""Mock DNS CAA lookup that re…Browse by section
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