Issue parsing HCL object within a block

[raz-bn]

Hey, I am trying to parse terraform HCL into Golang struct and im facing issues when trying to parse an object inside a Module block. this it the example I am trying to make work: Terraform file:

module "s3_bucket" {
  source = "terraform-aws-modules/s3-bucket/aws"
  bucket = "my-s3-bucket"
  versioning = {
    enabled = true
  }
}

Golang struct:

type Attributes struct {
	Source     string     `hcl:"source,attr"`
	Bucket     string     `hcl:"bucket,attr"`
	Versioning Versioning `hcl:"versioning,attr"`
}

type Versioning struct {
	Enabled bool `hcl:"enabled,attr"`
}

I am being able to parse both of source and bucket attributes, however, no matter what I try I was not able to parse the versioning attribute.

[apparentlymart]

Hi @raz-bn,

The "hcl" struct tags only interact with HCL blocks and their direct attributes. From HCL's perspective that versioning argument is just a single expression evaluated all at once, so HCL does not destructure it.

gohcl handles each attribute by passing it to gohcl.DecodeExpression, which in turn delegates to a third-party package gocty to convert to the final type. Therefore you would need to use that package's struct tags for your type Versioning:

type Versioning struct {
	Enabled bool `cty:"enabled"`
}