Preserve comments (in some way)

[dnmvisser]

We're using YAML format for our Terraform tfvars files. This allows for comments, and is easy to parse by standard utilities. We already were using a shell wrapper, so this was fairly easy to do. Basically we added a yq step to convert the YAML file to a temp JSON file which can be used by Terraform. So far so good.

But we also have quite a few existing .tfvars iles. I used hcl2tojson here to convert those and while that works:

hcl2tojson --strip-string-quotes --with-comment terraform.tfvars

, JSON obviously does not know about comments. I see that they're there though, as a list of dicts like this:

  "__comments__": [
    {
      "value": "VPC"
    },
    {
      "value": "IPv6 related"
    },
    {
      "value": "VPC Flow Logs"
    },
    {
      "value": "VPC Peering"
    },
    {
      "value": "AWS WAF"
    },
    {
      "value": "RDS"
    },
etc etc

But I don't see how they can be useful with context? Am I missing something?

My goal is to convert a commented .tfvars file to a commented YAML file.
I know that ruamel.yaml has support for commented YAML files.
I wonder if it is possible for python-hcl2 to export an HCL data structure in a way that ruamel.yaml understands...?

So that eventually one could do something like:

hcl2yaml terraform.tfvars > terraform.tfvars.yaml

thx!!