Reference library

Python Code Samples

Medium snippets you can copy, study, and run in the browser editor.

9 matches
Automation & scripting medium

Find Zombie Processes on Linux with Python

Parse the output of `ps -eo pid,stat,comm` to detect processes in zombie state (Z) on a Linux system and report their PIDs and commands.

linux process monitoring
Python
#!/usr/bin/env python3
import os
import subprocess

def find_zombie_processes():
    """Find zombie processes (state 'Z') running on Linux."""
    try:
        result = subprocess.run(['ps', '-eo', 'pid,stat,comm'], capture_output=True, text=True, check=True)
        zombies = []
        for line in result.stdout.stri…
37 0 Open
Automation & scripting medium

How to Detect Applications Consuming Excessive Memory in Python

Use psutil to list the top memory-using processes by RSS and print their names, PIDs, and memory usage in MB.

psutil memory monitoring
Python
import psutil

def find_top_memory_processes(limit=5):
    """Return top `limit` processes by memory usage (RSS)."""
    processes = []

    for proc in psutil.process_iter(['pid', 'name', 'memory_info']):
        try:
            info = proc.info
            mem = info['memory_info'].rss if info['memory_info'] else 0…
35 0 Open
Concurrency & performance medium

How to Demonstrate the GIL with Python Threads vs Processes

Measure and compare wall-clock time for CPU-bound work using Python threads (limited by the GIL) versus multiprocessing (which bypasses the GIL).

gil threading multiprocessing
Python
import threading
import multiprocessing
import time
import os


def cpu_heavy(n):
    return sum(i * i for i in range(n))


def run_threads(n):
    threads = [threading.Thread(target=cpu_heavy, args=(n,)) for _ in range(2)]
    start = time.perf_counter()
    for t in threads:
        t.start()
    for t in threads:
 …
11 0 Open
Concurrency & performance medium

How to Share Memory Between Processes in Python with multiprocessing.Value and Array

Share a numeric value and a list-like array across multiple Python processes using multiprocessing.Value and multiprocessing.Array, with each process modifying the same memory.

multiprocessing shared-memory concurrency
Python
import multiprocessing

def worker(shared_value, shared_array, index):
    shared_value.value += 10
    shared_array[index] = shared_array[index] * 2

if __name__ == "__main__":
    shared_value = multiprocessing.Value("i", 5)
    shared_array = multiprocessing.Array("i", [1, 2, 3, 4, 5])

    processes = []
    for i…
13 0 Open
Concurrency & performance medium

How to Share a Dict and List Between Processes with multiprocessing Manager in Python

This code demonstrates how to share a dictionary and a list between multiple processes using multiprocessing.Manager, enabling safe concurrent updates.

multiprocessing manager shared-state
Python
import multiprocessing as mp


def worker(shared_dict, shared_list, name):
    shared_dict[name] = name.upper()
    shared_list.append(name)
    print(f"{name} added to shared structures")


def main():
    with mp.Manager() as manager:
        shared_dict = manager.dict()
        shared_list = manager.list()

       …
13 0 Open
Concurrency & performance medium

How to Share a Queue Between Processes in Python

Use multiprocessing.Queue to pass work from a producer process to multiple consumer processes, coordinating with a sentinel stop message.

multiprocessing queue concurrency
Python
import multiprocessing
import time


def producer(queue, items):
    for item in items:
        queue.put(item)
        time.sleep(0.1)
    queue.put("STOP")


def consumer(queue, name):
    while True:
        item = queue.get()
        if item == "STOP":
            break
        print(f"{name} processed: {item}")

…
13 0 Open
Streaming & messaging medium

Batch Consume Process Commit Pattern in Python

A mock batch processor that accumulates items in a queue, processes full batches, commits successful or failed results, and flushes remaining items.

streaming batch-processing queues
Python
import random
import threading
import time
from collections import deque


class MockBatchProcessor:
    def __init__(self, process_func, commit_func, batch_size=5):
        self.queue = deque()
        self.batch_size = batch_size
        self.process_func = process_func
        self.commit_func = commit_func

    de…
13 0 Open
Reliability & rate limiting medium

At Least Once with Idempotent Consumer in Python

Implements a thread-safe idempotent consumer that processes each unique message exactly once, even when a producer sends duplicates under an at-least-once delivery model.

idempotency at-least-once threading
Python
import threading
import time
import uuid
from collections import Counter


class IdempotentConsumer:
    def __init__(self):
        self.processed = set()
        self._lock = threading.Lock()

    def consume(self, message_id, payload):
        with self._lock:
            if message_id in self.processed:
          …
15 0 Open
Big data & Spark medium

How to Mock Spark Streaming Micro-Batches in Python

Simulate Spark's micro-batch streaming with a simple deque-based class that collects events over time and processes them in timed batches.

spark streaming micro-batch
Python
import time
from collections import deque
from datetime import datetime


class MicroBatchStream:
    def __init__(self, batch_interval_sec=2):
        self.batch_interval = batch_interval_sec
        self.source = deque()
        self.processed = []

    def add_events(self, events):
        self.source.extend(events…
13 0 Open

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