回答

参考代码

#!/usr/local/python3/bin/python3
# -*- coding: utf-8 -*
import time
import random
from functools import wraps


def retry_on_failure(max_retries=3, delay=1, allowed_exceptions=()):
    """
    函数调用出错重试装饰器
    
    参数:
        max_retries (int): 最大重试次数，默认为3
        delay (int): 每次重试之间的延迟时间(秒)，默认为1
        allowed_exceptions (tuple): 允许重试的异常类型，默认为空(所有异常都重试)
    """
    def decorator(func):
        @wraps(func)
        def wrapper(*args, **kwargs):
            retries = 0
            last_exception = None
            
            while retries < max_retries:
                try:
                    return func(*args, **kwargs)
                except allowed_exceptions if allowed_exceptions else Exception as e:
                    last_exception = e
                    retries += 1
                    if retries < max_retries:
                        print(f"调用 {func.__name__} 失败，第 {retries} 次重试... (错误: {str(e)})")
                        time.sleep(delay)
            
            print(f"函数 {func.__name__} 在 {max_retries} 次尝试后仍然失败")
            raise last_exception
        return wrapper
    return decorator


# 示例使用
@retry_on_failure(max_retries=3, delay=1, allowed_exceptions=(ValueError, RuntimeError))
def unreliable_function(x):
    """一个可能失败的示例函数"""
    if random.random() < 0.7:  # 70%的概率失败
        raise ValueError("随机失败: 数值错误")
    return x * 2


# 测试代码
if __name__ == "__main__":
    try:
        result = unreliable_function(5)
        print(f"调用成功，结果: {result}")
    except Exception as e:
        print(f"最终失败: {str(e)}")