Reference library

Reliability & rate limiting

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

4 matches

How to Implement a Temporary Block in Python

Build a reusable PenaltyBox class that temporarily blocks access after a failure and reports remaining lockout time.

class PenaltyBox:
    def __init__(self, block_seconds: int = 30):
        self.block_seconds = block_seconds
        self._blocked_until = 0.0
        self._attempts = 0

    def try_access(self, current_time: float) -> bool:
        if self._blocked_until and current_time < self._blocked_until:
            return Fa…

14 0 Open

Reliability & rate limiting easy

How to Mock a Slow Startup Probe in Python

Simulate slow service initialization with a configurable mock delay to test readiness probes.

startup probe mock reliability

Python

import time
from dataclasses import dataclass, field


@dataclass
class StartupProbe:
    name: str
    min_wait_sec: float = 0.5
    max_wait_sec: float = 2.0
    _ready: bool = field(default=False, init=False, repr=False)

    def initialize(self) -> None:
        """Simulate slow startup with a fixed mock delay."""…

13 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

Reliability & rate limiting medium

Leaky Bucket Rate Limiter in Python: Smooth Burst Traffic

Implements a token-bucket-style leaky bucket rate limiter that smooths bursty traffic by draining at a fixed rate and dropping excess packets.

rate-limiting traffic-shaping simulation

Python

import time
import random


class LeakyBucket:
    def __init__(self, capacity, drain_rate):
        self.capacity = capacity
        self.drain_rate = drain_rate
        self.water = 0.0
        self.last_time = time.time()

    def allow(self, packet_size=1.0):
        now = time.time()
        elapsed = now - self.…

14 0 Open

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