Cloud Stack: Allow importing by slug (#859)

This will be useful for Crossplane where we'll be able to provide the slug and it will either create a new stack OR bring an existing one into management

Author: julienduchesne

docs/resources/cloud_stack.md

@@ -73,5 +73,6 @@ available at “https://<stack_slug>.grafana.net".
 Import is supported using the following syntax:
 
 ```shell
-terraform import grafana_cloud_stack.stack_name {{stack_id}}
+terraform import grafana_cloud_stack.stack_name {{stack_id}} // import by numerical ID
+terraform import grafana_cloud_stack.stack_name {{stack_slug}} // or import by slug
 ```

examples/resources/grafana_cloud_stack/import.sh

@@ -1 +1,2 @@
-terraform import grafana_cloud_stack.stack_name {{stack_id}}
+terraform import grafana_cloud_stack.stack_name {{stack_id}} // import by numerical ID
+terraform import grafana_cloud_stack.stack_name {{stack_slug}} // or import by slug

internal/resources/cloud/resource_cloud_stack.go

@@ -37,8 +37,21 @@ func ResourceStack() *schema.Resource {
 		DeleteContext: DeleteStack,
 		ReadContext:   ReadStack,
 
+		// Import either by ID or slug
 		Importer: &schema.ResourceImporter{
-			StateContext: schema.ImportStatePassthroughContext,
+			StateContext: func(c context.Context, rd *schema.ResourceData, meta interface{}) ([]*schema.ResourceData, error) {
+				_, err := strconv.ParseInt(rd.Id(), 10, 64)
+				if err != nil {
+					// If the ID is not a number, then it may be a slug
+					client := meta.(*common.Client).GrafanaCloudAPI
+					stack, err := client.StackBySlug(rd.Id())
+					if err != nil {
+						return nil, fmt.Errorf("failed to find stack by ID or slug '%s': %w", rd.Id(), err)
+					}
+					rd.SetId(strconv.FormatInt(stack.ID, 10))
+				}
+				return []*schema.ResourceData{rd}, nil
+			},
 		},
 
 		Schema: map[string]*schema.Schema{

internal/resources/cloud/resource_cloud_stack_test.go

@@ -79,6 +79,13 @@ func TestResourceStack_Basic(t *testing.T) {
 				ImportState:       true,
 				ImportStateVerify: true,
 			},
+			// Test import from slug
+			{
+				ResourceName:      "grafana_cloud_stack.test",
+				ImportStateId:     resourceName,
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
 		},
 	})
 }