I am using a null_resource in Terraform to execute an AWS CLI command for terraform version 1.5.1.

resource "null_resource" "update_aws_service" {
  depends_on = [aws_service.subservice]

  triggers = {
    always_run = "${timestamp()}"
  }

  provisioner "local-exec" {
    command = <<EOF
      aws service update-service 
      --aws-account-id ${var.aws_account_id} 
      --flag-a "${var.flag_a_value}" 
    EOF
    when = create
  }
}

I want to conditionally include the flag –flag-b ‘${var.flag_b_value}’ in the command only if the variable flag_b_value is defined and not empty. The command needs to remain valid and exclude the flag when the variable is not provided or is empty.

I attempted to use a conditional expression like this.

${var.flag_b != "" ? "--flag-b'${var.flag_b_value}'" : ""}

But I’m unsure if this is the best or correct way to achieve this.

Any guidance or alternative approaches would be appreciated!