describe_launch_configurations documentation with nonexistent parameter

[fariaass]

Describe the issue

The describe_launch_configurations api call documentation has a nonexistent parameter in Response Syntax. The parameter is "ClassicLinkVPCId", that is not present at both AWS API and AWS CLI docs. I am leaving reference links bellow.

Links

AWS Boto3 docs: https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/autoscaling/client/describe_launch_configurations.html
AWS API docs: https://docs.aws.amazon.com/autoscaling/ec2/APIReference/API_DescribeLaunchConfigurations.html
AWS CLI docs: https://docs.aws.amazon.com/cli/latest/reference/autoscaling/describe-launch-configurations.html

[RyanFitzSimmonsAK]

Hi @fariaass, thanks for reaching out. When you say "nonexistent parameter", do you mean that the field doesn't appear in an actual response? If so, could you provide debug logs demonstrating this behavior? Thanks!

[fariaass]

Hi @RyanFitzSimmonsAK! Yes, I was doing an automation with Lambda and some other services. When I called the describe_launch_configurations method and tried to access the "ClassicLinkVPCId" key, an error was returned to me. It was an IndexError, pointing that this key does not exist. So I went to the boto3 docs and compared with both AWS CLI and AWS API docs, where the key is not present. I will screenshots prints of code and logs.
Code:

CloudWatch Lambda Logs:

Thanks for the help!

[RyanFitzSimmonsAK]

Hi @fariaass, thanks for following up. I do want to quickly mention that the CLI and API docs do actually mention that ClassicLinkVPCId is returned, just like the Boto3 docs.

https://docs.aws.amazon.com/autoscaling/ec2/APIReference/API_LaunchConfiguration.html - API docs
CLI mentions it in the output section.

Anyway, the docs mention that this field exists for backward compatibility purposes, which is referring to EC2 Classic. EC2 Classic is deprecated, but older scripts might still need that functionality. If that field was set prior to the deprecation of EC2 Classic, it will be returned in the response. Otherwise, an empty field will not be returned. Fortunately, there isn't really a need to set the field ever since the deprecation. I hope that clears some things up, please let me know if you have any follow-up questions.

[fariaass]

Hi @RyanFitzSimmonsAK! Thanks for the explanation, I got it now. Sorry for spending your time with a mistake by my side!