• Cloud
• Terraform
• Validation

Cloud/Terraform/Validation

• Terraform variables can contain validations, from v1.10 they can also refer to other variables.

Problem with objects accepting any value

• By default object will ignore additional values passed in.

• Here is a method to validate strict set by using setsubtract - https://github.com/hashicorp/terraform/issues/33570#issuecomment-3079589065

    validation {
      error_message = <<-DOCS
        Firewall rule specs cannot contain unknown fields.
      DOCS
  
      condition = alltrue([
        for _, spec in var.firewall_rules : 0 == length(setsubtract(keys(spec), [
          "description",
          "priority",
          "source_subnets",
          "source_ranges",
          "source_tags",
          "source_service_accounts",
          "source_all",
          "target_tags",
          "target_service_accounts",
          "allow_tcp",
          "allow_udp",
          "allow_icmp"
        ]))
      ])
    }