What happens if a resource attribute is not referenced in a proper format in HCL?

When a resource attribute is not referenced in the proper format in HashiCorp Configuration Language (HCL), the configuration will throw an error. HCL has a strict syntax and structure that must be adhered to for Terraform to successfully parse and understand the desired infrastructure configuration. If an attribute is not referenced correctly, Terraform cannot determine what the user intends, leading to validation errors during the execution of the terraform apply or terraform plan commands.

This behavior ensures that only valid and correctly formatted configurations are processed, which helps prevent misconfigurations and unintended consequences in the infrastructure. Proper formatting typically involves correct referencing of resource attributes using the proper notation, such as ${resource_type.resource_name.attribute_name} or resource_type.resource_name.attribute_name.

If these formats are not followed, Terraform can neither evaluate the attribute values nor render resources properly, thereby generating an error acknowledgment in the console. This design emphasizes the importance of exact syntax in HCL, reinforcing good practices in infrastructure as code.