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System design patterns

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

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How to Build a Pipe and Filter Text Processing Chain in Python

A functional pipe-and-filter chain that transforms text through uppercase, whitespace normalization, number removal, stopword filtering, and file export.

pipeline text-processing functional

Python

import re
import sys


def pipe_filter_chain(stream):
    def uppercase(text):
        return text.upper()

    def strip_whitespace(text):
        return " ".join(text.split())

    def remove_numbers(text):
        return re.sub(r"\d+", "", text)

    def remove_stopwords(text, stopwords={"the", "and", "of", "in"}):…

16 0 Open

System design patterns medium

How to Build a Sidecar Logging Proxy in Python

Wrap any object with a proxy that transparently logs every method call, arguments, return value, and execution time to a file — mimicking a sidecar pattern.

proxy logging sidecar

Python

import logging
import time
from datetime import datetime


class LoggingProxy:
    """Sidecar-style proxy that logs all calls to a wrapped object."""

    def __init__(self, target, log_file="proxy.log"):
        self._target = target
        logging.basicConfig(
            filename=log_file,
            level=loggin…

15 0 Open

System design patterns medium

Singleton Config Loader in Python with Caution

Implements a singleton config loader in Python that reads JSON config files, but demonstrates the hidden gotcha of shared state across instances.

singleton config design-patterns

Python

import json
from pathlib import Path

class ConfigLoader:
    _instance = None

    def __new__(cls, *args, **kwargs):
        if cls._instance is None:
            cls._instance = super().__new__(cls)
        return cls._instance

    def __init__(self, config_file="config.json"):
        if not hasattr(self, "loaded…

12 0 Open

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