Reference library

Reliability & rate limiting

Retries, exponential backoff, circuit breakers, token buckets, and idempotent handlers.

3 matches

How to Send Messages to a Dead Letter Queue in Python

Simulates a poison message queue that retries failed messages up to a limit before moving them to a dead letter queue.

import json

class PoisonMessageQueue:
    def __init__(self, max_retries=3):
        self.dlq = []
        self.max_retries = max_retries
        self.processed_count = 0
        self.failed_count = 0

    def process_message(self, message_body):
        if "poison" in message_body:
            self.failed_count += 1…

15 0 Open

Reliability & rate limiting medium

How to Simulate an Outbox Pattern with Reliable Retry in Python

This code implements a mock outbox pattern with records, delivery attempts, and retries to simulate reliable message publishing.

outbox retry messaging

Python

import time
import itertools

class Outbox:
    def __init__(self):
        self._records = []
        self._seq = itertools.count(1)

    def publish(self, topic, payload):
        record = {
            "id": next(self._seq),
            "topic": topic,
            "payload": payload,
            "status": "pending"…

14 0 Open

Reliability & rate limiting medium

Retry with Exponential Backoff and Jitter in Python

A decorator-style retry wrapper that retries a flaky function with exponential backoff plus random jitter, then raises after the last attempt fails.

retry backoff jitter

Python

import random
import time

def retry_with_backoff(func, max_retries=3, base_delay=0.5, max_jitter=0.1):
    for attempt in range(max_retries + 1):
        try:
            return func()
        except Exception as e:
            if attempt == max_retries:
                raise
            delay = base_delay * (2 ** at…

14 0 Open

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