Feature: Get a long-lived client object

I have an a singleton object that encapsulates S3 uploads/download as well as marshal/unmarshal for a particular type of object & destination. I would like to have it encapsulate a long-lived client object. The best I can do so far is: (given it creates self.session in __init__.)

I call shutdown in global cleanup from signal handler.

1. Is there anything wrong with using a client in this way? It seems that getting a client per request when there could be many requests could wasteful as it (may?) do a network operation on creation (or why do we wait for it?).

2. If this is kosher, could there be a better interface for it?

    @property
    async def client(self) -> S3Client:
        """
        Get a client for S3.

        TODO: is there a better way to get a long-lived client?
        """
        if self._client is None:
            ctx = self.session.create_client(  # type: ignore
                service_name="s3",
                region_name=self.aws_region,
                aws_access_key_id=self.aws_access_key_id,
                aws_secret_access_key=self.aws_secret_access_key,
            )
            self._client = await ctx.__aenter__()
        return self._client

    async def shutdown(self) -> None:
        """
        Shutdown the client.
        """
        if self._client is not None:
            await self._client.close()
        self._client = None

[NicoAdrian]

@thehesiod lol 😃 thanks for the fixes

[thehesiod]

fix coming in https://github.com/aio-libs/aiobotocore/pull/935