Reference library

Reliability & rate limiting

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

3 matches

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

Reliability & rate limiting easy

How to implement an idempotency key store in Python

Build an in-memory idempotency key store with TTL that processes a request once and reuses the cached result for duplicate calls.

idempotency cache ttl

Python

import hashlib
import time
from typing import Dict, Optional


class IdempotencyStore:
    """Simple in-memory idempotency key store with mock processing."""

    def __init__(self, ttl_seconds: int = 3600) -> None:
        self.ttl = ttl_seconds
        self._store: Dict[str, tuple[str, float]] = {}

    def _is_expi…

15 0 Open

Reliability & rate limiting medium

How to retry idempotent operations with a mock in Python

Wrap a flaky idempotent operation in a retry loop with exponential backoff, and use unittest.mock to deterministically test the str's behavior.

retry backoff mock

Python

import random
import time
from unittest.mock import Mock


def idempotent_operation(value):
    """Simulate an idempotent operation that sometimes fails."""
    if random.random() < 0.6:  # 60% failure rate
        raise ConnectionError("Temporary failure")
    return value * 2


def retry_with_backoff(operation, max_…

14 0 Open

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