Parsing YAML Variables and Parameters to Terraform Configuration File

I am trying to read the value of a variable from my Terraform outputs.tf configuration file.

I have these 3 files in my Terraform project:

• azure-pipelines.yaml - my Azure pipeline YAML definition
• locals.tf - parse my azure-pipelines.yaml file with yamldecode and convert to a Terraform-compatible representation
• outputs.tf - print details of my Terraform resource/datasource/local/variable

My sole challenge here is to read the value of the Resource Group variable (and Parameter values also) from the azure-pipelines.yaml file and then write/display this in my outputs.tf Terraform configuration.

So far, the numerous attempts I've made, including the two examples currently shown in my outputs.tf file, have all failed to yield the desired result. Any idea how I can resolve this?

azure-pipelines.yaml:

name: "Terraform Pipeline_$(Date:yyyyMMdd)$(Rev:.r)"
trigger:
  branches:
    include:
      - main

parameters:

- name: name
  type: string
  default: testdata

- name: publishTestData
  type: boolean
  default: false
  displayName: Publish test data (optional)

variables:

- name: ResourceGroup
  value: 'rg-handsome-parakeet'

- name: subscriptionId
  value: xxxx-36xx-xxe9-x3x4-46xxxx400 

- name: backendServiceArm
  value: 'MyADOServicePrincipal' 

- name: storageAccountContainer
  value: 'terraform' 

- name: storageAccountKey
  value: 'tf.apim.tfstate' 

locals.tf:

locals {
  config  = yamldecode(file("azure-pipelines.yaml"))
}

outputs.tf:

output "get_local_file_variable" {

  #value = local.config.variables["ResourceGroup"]
  #value = local.config.${{variables.ResourceGroup}}

}

You can iterate over the variables and store the value when the name is ResourceGroup:

locals {
  config = yamldecode(file("azure-pipelines.yaml"))
}

locals {
  resource_group = [for var in local.config.variables : var.value if var.name == "ResourceGroup"][0]
}

output "get_local_file_variable" {
  value = local.resource_group
}

$ terraform plan

Changes to Outputs:
  + get_local_file_variable = "rg-needed-parakeet"