Support terraform source_paths as list of dicts

[tam116]

Which issue(s) does this change fix?

#4495

Why is this change necessary?

Terraform supports specifying source path several different ways including as a list of maps which translate to a list of dicts in SAM's python implementation

How does it address the issue?

Currently sam cli's terraform hook handles strings, list of strings, and dicts, but not list of dicts.

What side effects does this change have?

None

Mandatory Checklist

PRs will only be reviewed after checklist is complete

• [N/A] Add input/output type hints to new functions/methods
• [N/A] Write design document if needed (Do I need to write a design document?)
• Write/update unit tests
• [N/A] Write/update integration tests
• [N/A] Write/update functional tests if needed
• make pr passes
• [N/A] make update-reproducible-reqs if dependencies were changed
• [N/A] Write documentation

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[sriram-mv]

Thanks for the PR, could you showcase an example and also look at adding integration tests?

[tam116]

I think my change is covered by the existing integration tests

There are four ways to specify the source_path when using the 'terraform-aws-modules/lambda/aws' module. Terraform's documentation shows examples for both Style 1 and Style 4

module "my_lambda" {
  source = 'terraform-aws-modules/lambda/aws'
  # other configuration items

  # Style 1
  source_path = "/some/file/path"

  # Style 2
  source_path = ["/some/file/path"]
  
# Style 3
  source_path = {
    path = "/some/file/path"
    prefix_in_zip = "python"
    pip_requirements = true
  }

  # Style 4
  source_path = [
    {
      path = "/some/file/path"
      prefix_in_zip = "python"
      pip_requirements = true
    }
  ]
}

Previously only Styles 1,2, and 3 were supported by sam cli. If Style 4 was used sam cli would try to validate the path by calling isabs({path = "/some/file/path", prefix_in_zip = "python", pip_requirements = true}) which failed with "TypeError: expected str, bytes or os.PathLike object, not dict"

Since the existing _get_source_code_path() function already handles checking if the source_path is a string, dict, or list I thought the best way to support Style 4 would be to modify the "if list" logic and have it call _get_source_code_path() but passing the first element of the list as the source_path

Let me know if you have another questions about this PR

[mildaniel]

This makes sense to me, thanks for the contribution! I left a small question.

I also agree with @sriram-mv on the integration testing. Let's add a case that explicitly tests for source_path defined as a list of dicts. Since this wasn't working before, we probably aren't testing this exact case today. We can just add the a new module to one of the existing test cases with this particular format.

[tam116]

I've added integration tests and reworked the code remove the shallow copy and recursion

[hawflau]

Thanks for updating the PR. Just one small change request. Otherwise it's good!

[hawflau]

Thanks for your contribution! LGTM!