[REQ] Feature Request Description

Is your feature request related to a problem? Please describe.

Providing the inputs for AWS Signature V4 requires parsing the well defined default credential chain and config values for AWS and then passing them in a context. It would be convenient if when generating a go lang client, I could specify to always use the default credential chain and config for getting AWS credentials and AWS Region. If I know that the client will always need to authorize a request using AWS Signature V4, it would be nice if the client did not require a context value to be passed specifying I want to authorize using AWS Signature V4. Furthermore, it would be nice to be able to specify the service name for use in the AWS Signature V4 at client generation if it will be a value.

Describe the solution you'd like

A configuration option that will generate a client that always uses AWS Signature V4 for authorization, a configuration option that specifies the service name that will be used for the AWS Signature V4 authorization, and behavior that will pull the credentials and region from the default AWS configuration and credentials chain that AWS recommends as the mechanism for getting said information.

Describe alternatives you've considered

Creating a helper method in our own code base which would populate the ContextAWSv4 that is made available with the existing "withAWSV4Signature" configuration.

Additional context

Start by locating the Go client generation configuration and the existing "withAWSV4Signature" option. Investigate how generated clients receive ContextAWSv4, then determine the scope for default AWS credential and region loading, fixed service names, and always-on signing. Done should include agreed configuration behavior and coverage for generated clients, but the issue names no specific files or tests.