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System design patterns

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

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System design patterns medium

Lazy loading with a proxy in Python: defer expensive service creation

A lazy proxy defers creating an expensive service object until its method is first called, then caches it for reuse.

proxy lazy-loading design-patterns
Python 
import time
import random


class ExpensiveService:
    def __init__(self, name):
        self.name = name
        print(f"Creating expensive service: {self.name}")

    def fetch_data(self):
        time.sleep(1)
        return f"Data from {self.name}: {random.randint(1, 100)}"


class LazyProxy:
    def __init__(sel…
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