Small fixes to roles resource (#760)

This fixes the reference in the doc, and validate empty id of
permissions.

Author: therve

datadog/resource_datadog_role.go

@@ -7,6 +7,7 @@ import (
 	"github.com/DataDog/datadog-api-client-go/api/v2/datadog"
 	"github.com/hashicorp/terraform-plugin-sdk/helper/customdiff"
 	"github.com/hashicorp/terraform-plugin-sdk/helper/schema"
+	"github.com/hashicorp/terraform-plugin-sdk/helper/validation"
 )
 
 // validPermissions is a map of all unrestricted permission IDs to their name
@@ -92,9 +93,10 @@ func getRolePermissionSchema() *schema.Resource {
 	return &schema.Resource{
 		Schema: map[string]*schema.Schema{
 			"id": {
-				Type:        schema.TypeString,
-				Required:    true,
-				Description: "ID of the permission to assign.",
+				Type:         schema.TypeString,
+				Required:     true,
+				Description:  "ID of the permission to assign.",
+				ValidateFunc: validation.StringIsNotEmpty,
 			},
 			"name": {
 				Type:        schema.TypeString,

docs/resources/role.md

@@ -16,10 +16,10 @@ data "datadog_permissions" "bar" {}
 resource "datadog_role" "foo" {
   name  = "foo"
   permission {
-    id = "${data.datadog_permissions.bar.permissions.<name_of_permission_1>.id}"
+    id = data.datadog_permissions.bar.permissions.monitors_downtime
  }
   permission {
-    id = "${data.datadog_permissions.bar.permissions.<name_of_permission_2>.id}"
+    id = data.datadog_permissions.bar.permissions.monitors_write
  }
 }
 ```