Is There a Way to Generate Anonymous Blocks with Variable References

[SachithKasthuriarachchi]

Hi, Is there any guide on generating something like the following in go?

data = {
    config.hcl = data.template_file.vault_config.rendered
}

Attempt

dataMap := map[string]cty.Value{
		"config.hcl": cty.StringVal("data.template_file.vault_config.rendered"),
}
body.SetAttributeValue("data", cty.ObjectVal(dataMap))

However this generates the following (with quotes)

data = {
    "config.hcl" = "data.template_file.vault_config.rendered"
}

[bschaatsbergen]

Hi @SachithKasthuriarachchi,

It seems you're trying to assign a map/object type to the data attribute. From what I know, you'll need to use the lower-level API, hclsyntax, and work with tokens to achieve this. However, if you're setting the attribute like this: config.hcl = data.template_file.vault_config.rendered inside a block, it’s simpler, and you can keep using hclwrite.

Building a map/object and assigning it to an attribute

Start by using hclwrite to create a new empty file and build up the tokens for config.hcl and its value:

file := hclwrite.NewEmptyFile()
body := file.Body()

dataBody := hclwrite.NewEmptyFile().Body()

dataBody.SetAttributeTraversal("config.hcl", hcl.Traversal{
	hcl.TraverseRoot{Name: "data"},
	hcl.TraverseAttr{Name: "template_file"},
	hcl.TraverseAttr{Name: "vault_config"},
	hcl.TraverseAttr{Name: "rendered"},
})

dataTokens := dataBody.BuildTokens(nil)

If you print the dataTokens, you’ll see config.hcl = data.template_file.vault_config.rendered.

Next, we’ll set the data attribute and add the assignment for a map/object value by setting the equal token (=) and wrapping config.hcl with the opening ({) and closing brace token (}).

Here’s how we build the tokens:

dataAttrTokens := hclwrite.Tokens{
	&hclwrite.Token{
		Type:  hclsyntax.TokenEqual,
		Bytes: nil,
	},
	&hclwrite.Token{
		Type:  hclsyntax.TokenOBrace,
		Bytes: []byte("{\n"),
	},
}
dataAttrTokens = append(dataAttrTokens, dataTokens...)
dataAttrTokens = append(dataAttrTokens, &hclwrite.Token{
	Type:  hclsyntax.TokenCBrace,
	Bytes: []byte("}"),
})

This wraps the config.hcl key with an equal sign and braces.

Finally, we assign the dataAttrTokens to the data attribute to complete the map/object:

body.SetAttributeRaw("data", dataAttrTokens)
hclwrite.Format(file.Bytes())

Note that we format the file bytes to handle any whitespace issues due to the token wrangling we’ve done.

I hope this was helpful and exactly what you were looking for.​
h/t @picatz for collaborating on this with me.