Get resource_count information for configured tfe_workspace resources

[lucymhdavies]

Use-cases

When reading a workspace with the tfe_workspace data source, it is possible to identify how many resources that workspace is currently managing.
See https://registry.terraform.io/providers/hashicorp/tfe/latest/docs/data-sources/workspace#resource_count

However, when we create the workspace with the tfe_workspace resource, we do not get that information back in the attributes.

While it is already possible to write a sentinel policy that prevents deletion of workspaces:
hashicorp/terraform-sentinel-policies#3
Not having the resource_count attribute available in the tfe_workspace resource prevents us from writing a more complex sentinel policy, along the lines of "do not allow deletion of a workspace, unless it currently does not manage any resources"

Proposal

As part of dataSourceTFEWorkspaceRead we have:
https://github.com/hashicorp/terraform-provider-tfe/blob/main/tfe/data_source_workspace.go#L179

	d.Set("resource_count", workspace.ResourceCount)

We could add that to the resource schema as Computed: true, and include that same d.Set in resourceTFEWorkspaceRead to make that information available:
https://github.com/hashicorp/terraform-provider-tfe/blob/main/tfe/resource_tfe_workspace.go#L332

Other attributes read by the data source could be added too, if they would be useful, though resource_count is the one I have an immediate use-case for.

If this seems like a sensible approach, I can raise a PR to implement this.

[lucymhdavies]

That idea appears to work.

With this change:

diff --git a/tfe/resource_tfe_workspace.go b/tfe/resource_tfe_workspace.go
index d94d79d..0cf297e 100644
--- a/tfe/resource_tfe_workspace.go
+++ b/tfe/resource_tfe_workspace.go
@@ -203,6 +203,11 @@ func resourceTFEWorkspace() *schema.Resource {
                                        },
                                },
                        },
+
+                       "resource_count": {
+                               Type:     schema.TypeInt,
+                               Computed: true,
+                       },
                },
        }
 }
@@ -345,6 +350,8 @@ func resourceTFEWorkspaceRead(d *schema.ResourceData, meta interface{}) error {
        d.Set("working_directory", workspace.WorkingDirectory)
        d.Set("organization", workspace.Organization.Name)

+       d.Set("resource_count", workspace.ResourceCount)
+
        var sshKeyID string
        if workspace.SSHKey != nil {
                sshKeyID = workspace.SSHKey.ID

And this added to my Terraform configuration:

output "workspace_resource_count" {
  value = tfe_workspace.workspace["webserver-aws-test"].resource_count
}

Then...

$ terraform refresh
...
Outputs:

workspace_resource_count = 34

So I expect adding something similar for the other attributes available in the data source would work similarly.

[annawinkler]

Issue addressed via #682

[lucymhdavies]

Awesome stuff!

That'll definitely be useful, though my use case in particular is actually solved by a much more useful feature we recently added: Safe Delete!
hashicorp/terraform#31949 for other folks' reference