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System design patterns

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

3 matches

Build a BFF (Backend for Frontend) Mock Aggregator in Python

A minimal HTTP server implementing the BFF pattern that aggregates user data and orders from two mock backends into a single JSON response.

bff http-server aggregation

Python

import json
from http.server import BaseHTTPRequestHandler, HTTPServer
from urllib.parse import urlparse


class MockBackendA:
    def get_user(self, user_id):
        return {"id": user_id, "name": "Alice", "service": "backend-a"}


class MockBackendB:
    def get_orders(self, user_id):
        return [
            {…

17 0 Open

System design patterns easy

How to Aggregate Mock API Routes by Method in Python

Groups mock API routes by path and method, collecting response bodies and counts into a nested dictionary structure.

defaultdict api-gateway aggregation

Python

from collections import defaultdict


def aggregate_mock_routes(routes):
    """Aggregate mock API routes by method and aggregate their response bodies."""
    aggregated = defaultdict(lambda: defaultdict(list))

    for route in routes:
        method = route["method"]
        path = route["path"]
        response = …

13 0 Open

System design patterns easy

How to Take Periodic Snapshots of Aggregate State in Python

Build a Python class that accumulates values and periodically captures immutable snapshots of total, count, and average for later analysis.

aggregation snapshots state-management

Python

import time
import random
from collections import defaultdict


class SnapshotAggregator:
    def __init__(self):
        self.total = 0
        self.count = 0
        self.history = []

    def add(self, value):
        self.total += value
        self.count += 1

    def snapshot(self):
        avg = self.total / se…

13 0 Open

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