Why do some resources have a name and a “name” attribute?

问题

I am new to Terraform and trying to create some resources on Azure. To me it looks like there is some unnecessary duplication between the resource name and the attribute name in the definitions.

resource "azurerm_resource_group" "group_name" {
  name     = "group_name" # <-- repeated!
  location = "${local.location}"
}

Is there a difference? Can I somehow set them to be the same in the spirit of this:

resource "azurerm_resource_group" "group_name" {
  name     = "${name}"
  location = "${local.location}"
}

回答1:

The two names here serve different purposes and have different scopes.

The name that appears in the block header is a local name used within a single Terraform module. It is useful when interpolating results from one resource into another, like ${azurerm_resource_group.group_name}. The remote API never sees this name; it is used only for internal references.

The name within the block is an attribute specific to the resource type itself -- azurerm_resource_group in this case. This name will be sent to the remote API and will be how the object is described within the AzureRM system itself.

In simple configurations within small organizations it is indeed possible that both of these names could match. In practice, the difference in scope between these names causes them to often vary. For example:

If there are multiple separate teams or applications sharing an AzureRM account, the name used with the API may need to be prefixed to avoid collisions with names created by other teams or applications, while the local name needs to be unique only within the module where it's defined.
In more complex usage with child modules, it's common to instantiate the same child module multiple times. In this case, the local name will be the same between all of the instances (because it's significant only within that instance) but the name used with the API will need to be adjusted for each instances so that they don't collide.

回答2:

The resource name is the name you use to refer to the resource in Terraform context. The name parameter is the name given to the resource inside your provider's context. Resource don't have to have a name parameter, for example AWS Elastic IP resource doesn't have a name because AWS doesn't allow you to name them. Some of the resource like AWS Security group rule don't even translate one to one to resources you can name.

来源：https://stackoverflow.com/questions/46716154/why-do-some-resources-have-a-name-and-a-name-attribute

标签

terraform