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Python Code Samples

Copy-ready Python snippets by topic and difficulty — short, focused, and runnable in the browser editor.

4 matches
Concurrency & performance easy

How to Test HTTPX Async Client Pool Reuse with Mocks in Python

Mock an httpx.AsyncClient to verify connection pool reuse by asserting GET calls share a single client instance across concurrent async requests.

httpx async-await mock
Python 
import asyncio
import httpx
from unittest.mock import AsyncMock, patch, Mock

async def fetch_with_pool(client, url, n_reuses=3):
    results = []
    for i in range(n_reuses):
        resp = await client.get(url)
        results.append(resp.status_code)
        await asyncio.sleep(0)  # yield to loop to mimic real us…
13 0 Open
System design patterns medium

Object Pool Pattern for Database Connections in Python

Implements a reusable connection pool with acquire/release and context manager support, mocking database connections with idle reuse and exhaustion handling.

object-pool connection-pool databases
Python 
import time
from contextlib import contextmanager
from collections import deque


class ConnectionPool:
    def __init__(self, size=3, max_idle=5):
        self._idle = deque(maxlen=max_idle)
        self._active = set()
        self.size = size

    def _create(self):
        return {"created_at": time.time(), "queri…
12 0 Open
Database scaling & optimization medium

How to Build a Connection Pool Reuse Mock in Python

Build a mock connection pool with context manager to track connection reuse, acquires, and releases in Python.

connection-pool context-manager database
Python 
import time
from contextlib import contextmanager


class Connection:
    def __init__(self, name):
        self.name = name
        self.in_use = False
        self.busy_since = None

    def fetch(self):
        return f"data from {self.name}"


class ConnectionPool:
    def __init__(self, size=3):
        self.conn…
13 0 Open
Production deployment patterns medium

How to Drain a Connection Pool Before Exit in Python

Gracefully close all pooled sockets using a thread-safe ConnectionPool that drains connections before program exit.

connection-pool sockets threading
Python 
import socket
import threading
import time
import random

class ConnectionPool:
    def __init__(self, size=5):
        self.pool = []
        self.lock = threading.Lock()
        self.closed = False
        for _ in range(size):
            self.pool.append(self.create_connection())
    
    def create_connection(sel…
13 0 Open

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