retrylite 0.1.2

Zero-dependency retry decorator (sync & async)

retrylite

Zero-dependency retry decorator for Python (sync & async) with circuit-breaker, retry-after, and full type safety.

Features

• Zero runtime dependencies – only std-lib.
• Sync & Async support.
• Exponential backoff & full jitter.
• Circuit-breaker support.
• Respects Retry-After header.
• Test coverage & mypy strict.
• PyPI wheel < 10 kB.

Installation

pip install retrylite

Quick Start

Synchronous

from retrylite import retry
import requests

@retry(max_attempts=3, backoff=1.5)
def fetch(url):
    resp = requests.get(url, timeout=5)
    resp.raise_for_status()
    return resp.json()

try:
    data = fetch("https://httpbin.org/json")
except requests.HTTPError:
    print("Final failure after 3 retries")

Asynchronous

import aiohttp
from retrylite import aretry

@aretry(max_attempts=3, backoff=1.5)
async def fetch(url):
    async with aiohttp.ClientSession() as s:
        async with s.get(url) as resp:
            resp.raise_for_status()
            return await resp.text()

html = asyncio.run(fetch("https://httpbin.org/json"))

Advanced

Circuit-breaker

from retrylite import retry

@retry(break_on=(ValueError,))
def risky():
    raise ValueError("permanent")  # no retry

Retry-After header

from retrylite import retry
import requests

@retry(retry_after=True)
def api_call():
    resp = requests.get(url)
    resp.raise_for_status()  # respects 503 + Retry-After

Sample:

import time
import requests
import aiohttp
import asyncio
from retrylite import retry, aretry

# 1. Sync retry ---------------------------------
print("=== Sync Retry ===")
calls = 0

@retry(max_attempts=3, backoff=0.5, retry_after=True)
def fetch_sync(url: str) -> str:
    global calls
    calls += 1
    print(f"[Sync] attempt {calls}")
    resp = requests.get(url, timeout=3)
    resp.raise_for_status()
    return resp.text

try:
    html = fetch_sync("https://httpbin.org/status/503")
except requests.HTTPError:
    print("[Sync] Final failure (expected)")
print(f"[Sync] Total calls: {calls}\n")

# 2. Async retry --------------------------------
print("=== Async Retry ===")
calls = 0

@aretry(max_attempts=3, backoff=0.5, retry_after=True)
async def fetch_async(url: str) -> str:
    global calls
    calls += 1
    print(f"[Async] attempt {calls}")
    async with aiohttp.ClientSession() as s:
        async with s.get(url) as resp:
            resp.raise_for_status()
            return await resp.text()

try:
    html = asyncio.run(fetch_async("https://httpbin.org/status/503"))
except aiohttp.ClientResponseError:
    print("[Async] Final failure (expected)")
print(f"[Async] Total calls: {calls}\n")

# 3. Circuit-breaker demo ----------------------
print("=== Circuit-Breaker Demo ===")

@retry(max_attempts=5, break_on=(ValueError,), backoff=0.1)
def always_fail():
    raise ValueError("permanent")

try:
    always_fail()
except ValueError as e:
    print(f"[Circuit] Immediately raised: {e} (no retry)")

Development

git clone https://github.com/moehandi/retrylite.git
cd retrylite
poetry install
poetry run pre-commit install
poetry run pytest --cov
poetry build

License

MIT - see LICENSE