Python retry logic with exponential backoff using tenacity

from tenacity import (
    retry,
    stop_after_attempt,
    wait_exponential,
    wait_random_exponential,
    retry_if_exception_type,
    retry_if_result,
    before_sleep_log,
    after_log,
)
import httpx
import logging

logger = logging.getLogger(__name__)

# Basic exponential backoff
@retry(
    stop=stop_after_attempt(3),
    wait=wait_exponential(multiplier=1, min=1, max=10),  # 1s, 2s, 4s... capped at 10s
)
async def call_external_api(url: str) -> dict:
    async with httpx.AsyncClient() as client:
        response = await client.get(url)
        response.raise_for_status()
        return response.json()

# Full-featured: jitter + logging + selective retry
@retry(
    retry=retry_if_exception_type((httpx.TimeoutException, httpx.ConnectError)),
    wait=wait_random_exponential(min=1, max=60),  # Random jitter prevents thundering herd
    stop=stop_after_attempt(5),
    before_sleep=before_sleep_log(logger, logging.WARNING),
    reraise=True,  # Re-raise last exception after all attempts exhausted
)
async def embed_with_retry(text: str) -> list[float]:
    client = AsyncOpenAI()
    response = await client.embeddings.create(
        input=text,
        model='text-embedding-3-small',
    )
    return response.data[0].embedding

# Retry on specific HTTP status codes
async def is_retryable(response: httpx.Response) -> bool:
    return response.status_code in (429, 500, 502, 503, 504)

@retry(
    retry=retry_if_result(is_retryable),
    wait=wait_exponential(min=1, max=30),
    stop=stop_after_attempt(4),
)
async def api_call_with_status_retry(url: str) -> httpx.Response:
    async with httpx.AsyncClient() as client:
        return await client.get(url)  # Returns response even on retryable status

# Respect Retry-After header
import asyncio
async def call_with_retry_after(url: str) -> dict:
    async with httpx.AsyncClient() as client:
        for attempt in range(5):
            response = await client.get(url)
            if response.status_code == 429:
                retry_after = int(response.headers.get('Retry-After', 60))
                await asyncio.sleep(retry_after)
                continue
            response.raise_for_status()
            return response.json()
    raise RuntimeError('Max retries exceeded')