如何设计指数退避重试机制？tenacity库解决网络抖动的最佳实践

from tenacity import retry, stop_after_attempt, wait_exponential

@retry(stop=stop_after_attempt(5), wait=wait_exponential(multiplier=1, min=4, max=60))
def call_api(url):
    """
    调用API，使用指数退避重试。
    最多重试5次，等待时间以指数增长，最小4秒，最大60秒。
    """
    try:
        response = requests.get(url)
        response.raise_for_status()  # 抛出HTTPError，如果状态码不是200
        return response
    except requests.exceptions.RequestException as e:
        print(f"API调用失败: {e}")
        raise

# 示例用法
url = "https://example.com/api"
try:
    response = call_api(url)
    print("API调用成功:", response.json())
except Exception as e:
    print("API调用彻底失败:", e)

from tenacity import retry, stop_after_attempt, wait_exponential, retry_if_exception_type
import requests

def is_retryable_exception(exception):
    """
    判断异常是否应该重试。
    这里只重试特定状态码的HTTP错误。
    """
    if isinstance(exception, requests.exceptions.HTTPError):
        return exception.response.status_code in [500, 502, 503, 504]
    return False

@retry(stop=stop_after_attempt(5),
       wait=wait_exponential(multiplier=1, min=4, max=60),
       retry=retry_if_exception_type(requests.exceptions.RequestException) | retry_if_exception(is_retryable_exception))
def call_api(url):
    """
    调用API，使用指数退避重试。
    最多重试5次，等待时间以指数增长，最小4秒，最大60秒。
    只重试RequestException或者状态码为500, 502, 503, 504的HTTPError。
    """
    try:
        response = requests.get(url)
        response.raise_for_status()  # 抛出HTTPError，如果状态码不是200
        return response
    except requests.exceptions.RequestException as e:
        print(f"API调用失败: {e}")
        raise

# 示例用法
url = "https://example.com/api"
try:
    response = call_api(url)
    print("API调用成功:", response.json())
except Exception as e:
    print("API调用彻底失败:", e)