Observability & SRE
Structured logging, metrics, tracing, health checks, and SLO-friendly instrumentation.
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)")
…How to Generate and Propagate W3C Trace Context Headers in Python
Generate and propagate W3C traceparent and tracestate headers for distributed tracing in Python, with mock service headers.
import uuid
def generate_w3c_traceparent(trace_id=None, parent_id=None, flags="01"):
if trace_id is None:
trace_id = uuid.uuid4().hex[:32]
if parent_id is None:
parent_id = uuid.uuid4().hex[:16]
return f"00-{trace_id}-{parent_id}-{flags}"
def create_mock_headers(service_name, trace_id=N…How to Simulate Trace Sampling Head in Python
Simulate head-based probabilistic trace sampling on mock trace data with a configurable sample rate and optional seed for reproducibility.
import random
def trace_sampling_head(mock_traces, sample_rate=0.5, seed=None):
"""Simulate probabilistic trace sampling (head-based) on mock data.
Args:
mock_traces: list of trace dictionaries with a unique 'trace_id'
sample_rate: float 0.0-1.0, probability of keeping a trace
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Observability & SRE — Python code examples
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This page collects observability & sre snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.
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Samples are quick reference — one concept per page. For step-by-step teaching, use our Python tutorials. To test yourself, try quizzes or coding challenges. Clean up style with the Python formatter.