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Python Code Samples

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

8 matches
Comprehensions & generators medium

How to Build a Backpressure Generator Pause Producer Demo in Python

Demonstrates a producer–consumer pattern with a fixed-size buffer that pauses production when full, simulating backpressure.

backpressure producer-consumer deque
Python
import time
import collections

def producer(buffer, max_size, items):
    """Adds items to the buffer until full, then pauses."""
    for item in items:
        while len(buffer) >= max_size:
            print(f"Buffer full ({len(buffer)}/{max_size}) — producer paused")
            time.sleep(0.1)
        buffer.appe…
14 0 Open
Concurrency & performance medium

How to Build a Producer-Consumer Pattern with asyncio.Queue in Python

This code implements a classic producer-consumer pattern using asyncio.Queue to coordinate one producer task that generates items and two consumer tasks that process them concurrently, with a sentinel value to signal completion.

asyncio queue concurrency
Python
import asyncio
import random


async def producer(queue, item_count):
    for i in range(item_count):
        item = random.randint(1, 100)
        await queue.put(item)
        print(f"Produced: {item}")
        await asyncio.sleep(0.1)
    await queue.put(None)  # Sentinel to signal end


async def consumer(queue, n…
14 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
Concurrency & performance medium

How to Use a Bounded Buffer with threading.Condition in Python

Implement a thread-safe bounded buffer using threading.Condition and show a producer–consumer example with exact output.

threading condition producer-consumer
Python
import threading
import time
import random

class BoundedBuffer:
    def __init__(self, capacity):
        self.capacity = capacity
        self.buffer = []
        self.condition = threading.Condition()

    def put(self, item):
        with self.condition:
            while len(self.buffer) >= self.capacity:
       …
14 0 Open
Streaming & messaging medium

How to Implement Backpressure Pause Producer with a Bounded Queue in Python

Places a Producer thread that sends items into a bounded queue with backpressure: on Full, it pauses to let the consumer catch up.

queues backpressure threading
Python
import threading
import time
import queue
import random


class Producer:
    def __init__(self, q):
        self.q = q
        self.running = True

    def produce(self):
        while self.running:
            item = random.randint(1, 100)
            try:
                self.q.put(item, timeout=0.5)
              …
14 0 Open
Streaming & messaging medium

How to Mock a Kafka Producer Batch Send in Python

Simulate a Kafka producer in Python that sends batched JSON events with mock partitions and latency for testing streaming pipelines without a real broker.

kafka mock streaming
Python
import json
import random
import time
from datetime import datetime


class MockKafkaProducer:
    def __init__(self, topic):
        self.topic = topic
        self.sent_messages = []

    def send(self, value, key=None):
        message = {
            "topic": self.topic,
            "key": key,
            "value"…
13 0 Open
Caching & Redis medium

How to Mock Redis Streams Consumer Groups in Python

Simulate Redis Streams producer and consumer group behavior in Python using a standalone mock class for testing and development.

redis streams mock
Python
import time
import json
from collections import defaultdict

class RedisStreamMock:
    def __init__(self):
        self.streams = defaultdict(list)
        self.consumer_groups = defaultdict(dict)
        self.pending_entries = defaultdict(list)

    def xadd(self, stream, fields):
        entry_id = f"{time.time_ns(…
14 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

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