Fallback Functionality

[a2z72]

Hello,

Thanks for this wonderful library.

I'm wondering how to customize the behavior when all tries are exhausted to return None, even if the last request ended in an exception?

I understand the following from the documentation: "last request returns as it is.
If the last request ended with exception, that this exception will be raised from RetryClient request" - but I'd like to continue despite the exception raised by returning None.

[inyutin]

Hello, @a2z72 !

I'm afraid I don't quite understand your needs. Can you, please, describe everything more briefly ?
If I understand correctly, you want to receive None as a response, if the last request failed. Can you describe why do you need such functionality ?

Why not to do something like that then?

try:
    response = await aiohttp_client.request(...)
except:
    response = None

You can also set up a huge number of attempts, so there will be requests until success

[a2z72]

Hi @inyutin - thanks for your prompt reply.

Here's the code I'm trying to model the functionality of:

    while attempts <= max_tries:
        try:
            async with request("GET", url) as response:
                return await response.text("utf-8")
        except:
            attempts += 1
            continue
    return None # fallback

I would like to try the HTTP request X number of times, and if on the last request an exception is still thrown, the function will return None (instead of raising an exception).

[inyutin]

@a2z72 then code like that should fulfills your needs:

from aiohttp import ClientResponse
from aiohttp_retry import RetryClient, RandomRetry

async def make_requests(url: str, max_tries: int) -> Optional[ClientResponse]:
    retry_options = ExponentialRetry(attempts=max_tries)
    async with RetryClient(retry_options=retry_options, raise_for_status=True) as client:
          try:
              async with client.get(url) as response:
                  return response 
          except:
              # logger.warning/logger.exception
              return None   

I don't feel, that adding an option to return None instead of raw response in case of failure is a correct thing.
As I stated above it's pretty easy to achieve the behaviour you want. Maybe I don't get your request in a right way? Do you have any more questions?

[a2z72]

Thank you @inyutin.