1 import asyncio
 2 from typing import Callable, Awaitable, TypeVar
 3 
 4 T = TypeVar("T")
 5 
 6 async def retryer(
 7     func: Callable[[], Awaitable[T]],
 8     max_retries: int
 9 ) -> T:
10     """
11     Retry an async function with exponential backoff.
12 
13     :param func: async function with no parameters
14     :param max_retries: maximum number of retries (after first attempt)
15     :return: result of func()
16     :raises: last exception if all attempts fail
17     """
18     if max_retries < 0:
19         raise ValueError("max_retries must be >= 0")
20 
21     attempt = 0
22     delay = 2  # initial delay in seconds
23     max_delay = 16
24 
25     while True:
26         try:
27             return await func()
28         except Exception as e:
29             if attempt >= max_retries:
30                 raise e
31 
32             await asyncio.sleep(delay)
33 
34             delay = min(delay * 2, max_delay)
35             attempt += 1

 1 async def retryer(func, max_retries):
 2     delay = 2
 3     max_delay = 16
 4 
 5     for attempt in range(max_retries + 1):
 6         try:
 7             return await func()
 8         except Exception as e:
 9             if attempt == max_retries:
10                 raise e
11             await asyncio.sleep(delay)
12             delay = min(delay * 2, max_delay)

 1 import random
 2 import asyncio
 3 
 4 async def my_async_function():
 5     if random.random() < 0.7:
 6         raise ValueError("Random failure")
 7     return "Success!"
 8 
 9 async def main():
10     try:
11         result = await retryer(my_async_function, 3)
12         print("Result:", result)
13     except Exception as e:
14         print("Final failure:", e)
15 
16 asyncio.run(main())