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System design patterns

Sharding, load balancing, CAP tradeoffs, and scaling patterns — interview and production ready.

3 matches

How to Build a Health Check System with Instance Up and Down Status in Python

Track instance health by marking them up or down and simulating health checks with a mock class in Python.

from datetime import datetime
import random

class HealthChecker:
    def __init__(self):
        self.status = {}
    
    def mark_up(self, instance_id):
        self.status[instance_id] = {
            "state": "up",
            "last_check": datetime.now().isoformat(),
            "healthy": True
        }
    
  …

14 0 Open

System design patterns medium

How to Implement the Abstract Factory Pattern in Python

Implements the Abstract Factory pattern to create families of related GUI objects (buttons, checkboxes) without specifying their concrete classes.

abstract-factory design-patterns system-design

Python

from abc import ABC, abstractmethod


class Button(ABC):
    @abstractmethod
    def render(self):
        pass


class Checkbox(ABC):
    @abstractmethod
    def render(self):
        pass


class WindowsButton(Button):
    def render(self):
        return "Rendering Windows-style button"


class WindowsCheckbox(Chec…

13 0 Open

System design patterns medium

How to implement stale-while-revalidate caching in Python

A Python cache wrapper that returns a stale cached value with a fallback flag when the upstream fetch fails, using TTL-based freshness checks.

caching ttl resilience

Python

import time
from functools import lru_cache


class CachedService:
    def __init__(self, fetch_func, ttl=5):
        self.fetch_func = fetch_func
        self.ttl = ttl
        self._cache = {}
        self._timestamp = {}

    def get(self, key):
        now = time.time()
        if key in self._cache and now - self…

12 0 Open

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