fix: tcp_keepalive socket

[ShaneNolan]

When using the botocore.config.Config option tcp_keepalive=True, the TCP socket is configured with the keep alive socket option (socket.SO_KEEPALIVE). By default, Linux sets the TCP keepalive time parameter to 7200 seconds, which exceeds the AWS NAT Gateway default timeout of 350 seconds [source].

This limitation leads to an inability to receive a response from a Lambda function under the following conditions:

• The Lambda function is invoked in synchronous mode (InvocationType='RequestResponse').
• The invocation occurs within VPC where a NAT gateway is required to access the internet from a private subnet.
• The execution time of the Lambda function exceeds 350 seconds.

Therefore, by configuring socket.TCP_KEEPIDLE, socket.TCP_KEEPINTVL and socket.TCP_KEEPCNT when tcp_keepalive during the _compute_socket_options function call we can overcome this limitation.

socket.IPPROTO_TCP is used to support cross platform compatibility.

The code submitted automatically calculates these values based on the read timeout. Another option would be to have supplied in the scope/client object.

Fixes issues: boto/boto3#2424, boto/boto3#2510 and #2916.

Fargate recently had a similar solution implemented to support this use case: https://aws.amazon.com/blogs/containers/announcing-additional-linux-controls-for-amazon-ecs-tasks-on-aws-fargate/.

[adammcdonagh]

This is also impacting me. Unfortunately we are invoking Lambda from ECS via AWS Batch, which doesn't support adding these new options in the task definition yet.

[smasa1112]

This issue is same for me.
In my case, Lambda connection is read_timeout when EC2 by Codebuild try to connect lambda.
It is OK, when Lambda sleep 300sec but read_timeout is occured when Lambda sleep 450 sec.
EC2 by Codebuild doesn't join any VPC(Codebuild default)

[spawn-guy]

experiencing similar issues

File "/var/app/venv/staging-LQM1lest/lib64/python3.11/site-packages/botocore/retryhandler.py", line 247, in __call__
    return self._check_caught_exception(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/var/app/venv/staging-LQM1lest/lib64/python3.11/site-packages/botocore/retryhandler.py", line 416, in _check_caught_exception
    raise caught_exception
  File "/var/app/venv/staging-LQM1lest/lib64/python3.11/site-packages/aiobotocore/endpoint.py", line 181, in _do_get_response
    http_response = await self._send(request)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/var/app/venv/staging-LQM1lest/lib64/python3.11/site-packages/aiobotocore/endpoint.py", line 294, in _send
    return await self.http_session.send(request)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/var/app/venv/staging-LQM1lest/lib64/python3.11/site-packages/aiobotocore/httpsession.py", line 261, in send
    raise ReadTimeoutError(endpoint_url=request.url, error=e)
botocore.exceptions.ReadTimeoutError: Read timeout on endpoint URL: "https://lambda.eu-west-1.amazonaws.com/2015-03-31/functions/redacted/invocations"