Standardize google_compute_instance import ID

This patch changes the import ID of google_compute_instance to have a
format that is more consistent with other resources like
google_compute_subnetwork while still supporting the previously
supported import ID of {{project}}/{{zone}}/{{name}} in order to have
backwards compatibility.

google/resource_compute_instance.go

@@ -1773,16 +1773,20 @@ func resourceComputeInstanceDelete(d *schema.ResourceData, meta interface{}) err
 }
 
 func resourceComputeInstanceImportState(d *schema.ResourceData, meta interface{}) ([]*schema.ResourceData, error) {
-	parts := strings.Split(d.Id(), "/")
-
-	if len(parts) != 3 {
-		return nil, fmt.Errorf("Invalid import id %q. Expecting {project}/{zone}/{instance_name}", d.Id())
+	config := meta.(*Config)
+	if err := parseImportId([]string{
+		"projects/(?P<project>[^/]+)/zones/(?P<zone>[^/]+)/instances/(?P<name>[^/]+)",
+		"(?P<project>[^/]+)/(?P<zone>[^/]+)/(?P<name>[^/]+)",
+		"(?P<name>[^/]+)",
+	}, d, config); err != nil {
+		return nil, err
 	}
-
-	d.Set("project", parts[0])
-	d.Set("zone", parts[1])
-	d.Set("name", parts[2])
-	d.SetId(fmt.Sprintf("projects/%s/zones/%s/instances/%s", parts[0], parts[1], parts[2]))
+	// Replace import id for the resource id
+	id, err := replaceVars(d, config, "{{project}}/{{zone}}/{{name}}")
+	if err != nil {
+		return nil, fmt.Errorf("Error constructing id: %s", err)
+	}
+	d.SetId(id)
 
 	return []*schema.ResourceData{d}, nil
 }

website/docs/r/compute_instance.html.markdown

@@ -394,10 +394,12 @@ This resource provides the following
 -> **Note:** The `desired_status` field will not be set on import. If you have it set, Terraform will update the field on the next `terraform apply`, bringing your instance to the desired status.
 
 
-Instances can be imported using the `project`, `zone` and `name`, e.g.
+Instances can be imported using any of these accepted formats:
 
 ```
-$ terraform import google_compute_instance.default gcp-project/us-central1-a/test
+$ terraform import google_compute_instance.default projects/{{project}}/zones/{{zone}}/instances/{{name}}
+$ terraform import google_compute_instance.default {{project}}/{{zone}}/{{name}}
+$ terraform import google_compute_instance.default {{name}}
 ```
 
 [custom-vm-types]: https://cloud.google.com/dataproc/docs/concepts/compute/custom-machine-types