Reference library

Python Code Samples

Medium snippets you can copy, study, and run in the browser editor.

6 matches
System design patterns medium

Circuit Breaker Pattern in Python: Closed, Open, and Half-Open States

Implement a circuit breaker with closed, open, and half-open states to prevent repeated calls to failing services and allow recovery after a timeout.

circuit-breaker resilience fault-tolerance
Python
class CircuitBreaker:
    def __init__(self, failure_threshold=3, timeout_seconds=5):
        self.failure_threshold = failure_threshold
        self.timeout_seconds = timeout_seconds
        self.state = "closed"
        self.failure_count = 0
        self.last_failure_time = None

    def record_success(self):
     …
14 0 Open
API design & gRPC medium

How to Build a Hypermedia Collection Resource in Python

Creates a paginated hypermedia collection resource with HATEOAS links and embedded items.

hateoas hal pagination
Python
import json
import math


class HypermediaCollection:
    """A mock hypermedia collection resource."""

    def __init__(self, items, base_url="/api/items"):
        self.items = items
        self.base_url = base_url

    def to_dict(self, page=1, per_page=3):
        total = len(self.items)
        pages = math.ceil…
14 0 Open
Reliability & rate limiting medium

Circuit breaker failure threshold count in Python

Track consecutive or time-windowed failures with a deque to open a circuit breaker and auto-recover to half-open after a cooldown.

circuit-breaker resilience deque
Python
from collections import deque
from time import time, sleep


class CircuitBreaker:
    def __init__(self, failure_threshold: int = 5, recovery_time: float = 10.0):
        self.failure_threshold = failure_threshold
        self.recovery_time = recovery_time
        self.failures: deque[float] = deque()
        self.st…
16 0 Open
Reliability & rate limiting medium

How to Implement a Circuit Breaker in Python

A Python dataclass that provides circuit breaker logic with closed, open, and half-open states to fail fast on repeated errors.

circuit-breaker resilience fault-tolerance
Python
from dataclasses import dataclass
from datetime import datetime, timedelta
import time


@dataclass
class CircuitBreaker:
    failure_threshold: int = 3
    timeout_seconds: float = 5.0
    failures: int = 0
    state: str = "closed"
    last_failure: datetime = None

    def call(self, func):
        if self.state ==…
15 0 Open
Reliability & rate limiting medium

How to Mock a Circuit Breaker Reset Timeout in Python

This code implements a simple circuit breaker with a reset timeout test, simulating a flaky service to show half-open state transitions.

circuit-breaker reliability mock-testing
Python
import time
import random


class CircuitBreaker:
    def __init__(self, failure_threshold=3, reset_timeout=5):
        self.failure_threshold = failure_threshold
        self.reset_timeout = reset_timeout
        self.failure_count = 0
        self.last_failure_time = None
        self.state = "CLOSED"  # CLOSED (nor…
15 0 Open
Auth & security at scale medium

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.

acme letsencrypt http-server
Python
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…
16 0 Open

Browse by section

Each section groups closely related Python snippets.

Guide: free Python code samples library

Copy-ready Python snippets for learners and developers

PythonSkillset code samples are short, focused examples organised by topic and difficulty. Every snippet is server-rendered HTML — readable by search engines and easy to copy. Open any sample, read the notes, copy the code, then press Try in editor to run it in the browser with Pyodide.

How to use this library

  1. Pick a topic section — strings, lists, files, functions, and more
  2. Open a sample, read How it works, and copy the code block
  3. Run it in the IDE, tweak values, then take a related quiz or tutorial lesson

Samples vs tutorials and challenges

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.