When I was looking at tools I found the documentation for LocalStack more approachable than AWS SAM. Specifically how to get an LocalStack running in a Docker environment and using the traditional AWS CLI versus the SAM template file. Though, being a lot more familiar with Lambdas now and coming across this article I may have to give SAM another try: https://cbax.me/posts/2019/03/aws-sam-cli-inside-docker-compose/