AioJSONParser can't read the initial response from the stream

[bashalex]

Describe the bug

The library fails to read (seems like any) Stream response.

In particular, AioJSONParser fails to read the initial response from the stream.

When AioJSONParser.parse() is called, internally it calls _handle_event_stream() which tries to call the get_initial_response() method of the AioEventStream which expectedly fails to execute next(self._event_generator) since it is an Async Generator.

To reproduce, you can call the subscribe_to_shard() method of the Kinesis client:

async with self._session.create_client(
        'kinesis',
        region_name=AWS_REGION_NAME,
        aws_access_key_id=AWS_ACCESS_KEY_ID,
        aws_secret_access_key=AWS_SECRET_ACCESS_KEY,
) as client:
    starting_position = {
        'Type': 'LATEST'
    }
    response = await client.subscribe_to_shard(
        ConsumerARN=CONSUMER_ARN,
        ShardId=SHARD_ID,
        StartingPosition=starting_position
    )

Environment:

• Python Version: 3.9.5
• OS name and version: WSL 2 (Ubuntu 18)
• aiobotocore: 1.3.2
• botocore: 1.20.106

[thehesiod]

will look asap

[bashalex]

Thanks! Here is the stacktrace:

    ...
    response = await client.subscribe_to_shard(
  File "/home/bashalex/.cache/pypoetry/virtualenvs/asset-service-PCliylm9-py3.9/lib/python3.9/site-packages/aiobotocore/client.py", line 141, in _make_api_call
    http, parsed_response = await self._make_request(
  File "/home/bashalex/.cache/pypoetry/virtualenvs/asset-service-PCliylm9-py3.9/lib/python3.9/site-packages/aiobotocore/client.py", line 161, in _make_request
    return await self._endpoint.make_request(operation_model, request_dict)
  File "/home/bashalex/.cache/pypoetry/virtualenvs/asset-service-PCliylm9-py3.9/lib/python3.9/site-packages/aiobotocore/endpoint.py", line 89, in _send_request
    success_response, exception = await self._get_response(
  File "/home/bashalex/.cache/pypoetry/virtualenvs/asset-service-PCliylm9-py3.9/lib/python3.9/site-packages/aiobotocore/endpoint.py", line 122, in _get_response
    success_response, exception = await self._do_get_response(
  File "/home/bashalex/.cache/pypoetry/virtualenvs/asset-service-PCliylm9-py3.9/lib/python3.9/site-packages/aiobotocore/endpoint.py", line 182, in _do_get_response
    parsed_response = parser.parse(
  File "/home/bashalex/.cache/pypoetry/virtualenvs/asset-service-PCliylm9-py3.9/lib/python3.9/site-packages/botocore/parsers.py", line 245, in parse
    parsed = self._do_parse(response, shape)
  File "/home/bashalex/.cache/pypoetry/virtualenvs/asset-service-PCliylm9-py3.9/lib/python3.9/site-packages/botocore/parsers.py", line 778, in _do_parse
    parsed = self._handle_event_stream(response, shape, event_name)
  File "/home/bashalex/.cache/pypoetry/virtualenvs/asset-service-PCliylm9-py3.9/lib/python3.9/site-packages/botocore/parsers.py", line 791, in _handle_event_stream
    event = event_stream.get_initial_response()
  File "/home/bashalex/.cache/pypoetry/virtualenvs/asset-service-PCliylm9-py3.9/lib/python3.9/site-packages/botocore/eventstream.py", line 606, in get_initial_response
    initial_event = next(self._event_generator)
TypeError: 'async_generator' object is not an iterator

[thehesiod]

unfortunately can't use moto for testing since they don't support the required methods. oo man, this is going to require several patches and increase our footprint even more :(

[thehesiod]

@bashalex want to try the linked PR?

[bashalex]

Wow, that was rapid! Let me check it out.

[bashalex]

It works now, thanks for the quick resolution!
Looking forward to the PR being merged.