103 lines
3.1 KiB
Python
103 lines
3.1 KiB
Python
"""
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retry.py
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--------
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Exponential backoff retry helpers for API calls that may hit rate limits
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or transient server errors (429, 502, 503, 504).
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"""
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from __future__ import annotations
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import asyncio
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import functools
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import logging
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import time
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from typing import Callable, TypeVar
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logger = logging.getLogger(__name__)
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T = TypeVar("T")
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# HTTP status codes that are safe to retry
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_RETRYABLE_STATUS = {429, 500, 502, 503, 504}
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def retry_with_backoff(
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max_retries: int = 3,
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base_delay: float = 1.0,
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max_delay: float = 30.0,
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retryable_exceptions: tuple = (Exception,),
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):
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"""
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Decorator for sync functions. Retries on exceptions with exponential backoff.
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Usage:
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@retry_with_backoff(max_retries=3, base_delay=1.0)
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def my_api_call():
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...
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"""
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def decorator(fn: Callable) -> Callable:
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@functools.wraps(fn)
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def wrapper(*args, **kwargs):
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last_exc: Exception | None = None
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for attempt in range(max_retries + 1):
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try:
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return fn(*args, **kwargs)
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except retryable_exceptions as exc:
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last_exc = exc
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if attempt == max_retries:
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break
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delay = min(base_delay * (2 ** attempt), max_delay)
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logger.warning(
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"Retry %d/%d for %s after %.1fs — %s",
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attempt + 1, max_retries, fn.__name__, delay, exc,
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)
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time.sleep(delay)
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raise last_exc
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return wrapper
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return decorator
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def async_retry_with_backoff(
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max_retries: int = 3,
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base_delay: float = 1.0,
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max_delay: float = 30.0,
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retryable_exceptions: tuple = (Exception,),
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):
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"""
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Decorator for async functions. Retries on exceptions with exponential backoff.
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Usage:
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@async_retry_with_backoff(max_retries=3, base_delay=1.0)
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async def my_api_call():
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...
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"""
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def decorator(fn: Callable) -> Callable:
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@functools.wraps(fn)
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async def wrapper(*args, **kwargs):
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last_exc: Exception | None = None
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for attempt in range(max_retries + 1):
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try:
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return await fn(*args, **kwargs)
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except retryable_exceptions as exc:
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last_exc = exc
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if attempt == max_retries:
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break
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delay = min(base_delay * (2 ** attempt), max_delay)
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logger.warning(
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"Async retry %d/%d for %s after %.1fs — %s",
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attempt + 1, max_retries, fn.__name__, delay, exc,
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)
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await asyncio.sleep(delay)
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raise last_exc
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return wrapper
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return decorator
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class RateLimitError(Exception):
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"""Raised when an API returns HTTP 429 Too Many Requests."""
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def check_response_retryable(status_code: int) -> bool:
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"""Return True if the HTTP status code warrants a retry."""
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return status_code in _RETRYABLE_STATUS
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